Mitochondrial Donation (MRT)- success stories

The known risks associated with the MRT are more theoretical and practical, specifically for the patient population, which is an advanced maternal age population. What we are doing is a reconstruction of the cell. We are simply exchanging the environment where the DNA is developing. From the clinical perspective, all babies born in our project and in the projects we know are not developing, for the advanced maternal age babies, no adverse effects. They are all healthy and developing perfectly well, as any other natural conception baby or IVF treatment baby. This has been proven to be safe.

The amount of nuclear DNA is 99.9% because mitochondria carry only 37 genes, which are mainly responsible for the metabolic and immune responses in the body. They are not playing a role in phenotypical signs or any critical conditions. That’s why the known donor theoretically can be involved in this treatment, but we have never had cases like this because a known donor has no proven fertility. It will be very hard to select as good a donor as we are selecting throughout our process, and this will be a risk associated with the outcome for this particular patient. That’s why we do not advise doing this.

It is theoretically possible to use a relative for the egg donation, but, for example, donors we used for these technologies are up to 28 years old, already having proven fertility as their own child, and we know the morphological status of their oocytes and their performance in terms of IVF cycle outcome. If we are able to learn these predictive parameters from the individual who is going to be a donor, we may perform this treatment. But we never had a case like this. This can be discussed, but we will not be able to place the same expectations in terms of the cycle outcomes when doing this technology for two unknown individuals, the patient and her relative, who is her mitochondrial donation donor.

This is a perfect candidate for the mitochondrial replacement treatment, taking into account that there is already advanced maternal age, which is statistically correlated with a very low probability of natural conception or even a successful IVF cycle outcome. What we would discuss with such a patient is that we might recommend several cycles as accumulated cycles, resulting in two to three eggs every cycle. Then, thinking about probability, we would evaluate her implantation potential and discuss how many euploid embryos we would recommend having for a successful further journey.

Usually, AMH correlates with the numbers, but it does not always work 100% as a predictive model. If we have AMH 0.1, we expect to generate 1 healthy viable egg in this cycle. If we have 0.4, we have the potential to generate 4 eggs in this round. This will depend on every cycle because every cycle will have variability, and also depend on the stimulation protocol. We would try to choose the protocol and work on optimisation to maximise the number of eggs. This patient would be recommended to have multiple cycles, accumulate more eggs, and then run the MRT as the whole treatment.

I would like to note that we have picomoles and nanograms, and they are different. If we are talking here about nanograms, this will be a very high AMH, so we would expect to receive over 7 to 8 oocytes. We also need to correlate with the antral follicle count and with the FSH because, for such categories of the patient as we have seen in one of the cases, we may have shifted hormonal parameters where one parameter does not correspond to another. This can impact the receptivity of the follicles in terms of their response to the IVF cycles.

Definitely, we would recommend, as time is crucial if the patient wishes for IVF treatment and further implantation, to run a cycle and to freeze her biological material even before she chooses how to use them further. The vitrification method is currently a very safe method to preserve fertility. For us as clinicians, I say this because we also talk a lot about fertility preservation, and there is a topic discussing how old you can be to freeze your eggs. My answer is always: until you have them. Current technologies are very effective for future potential successful treatment, and vitrification is very safe if done properly. This is the way to preserve fertility at any age, and if there is a will to become a parent one day, when you just think about this, start to take action.

Yes, we use AI for each step of embryo development. For oocyte selection, the AI technology is in-house, developed for our use. For sperm selection, we use AI from the market. Proper AI is based on mathematical and statistical algorithms.

However, MRT is based on intracellular potential and the changes happening there. AI is not educated for this yet. What AI can help with is creating a score for the specific morphology of the oocytes, and we do this for donor oocytes. For patient oocytes, we do not do AI grading because for the majority, we would see them graded as yellow or red, very low score. But what is important in these biological materials is the inner structure and the viability, which we can assess only after we run the whole cycle, develop it to the blastocyst stage, and test these blastocysts. This is when we understand whether it was proper biological material.

Even seeing the spindle, this is something we are trying to educate AI for now, because we also evaluate spindles for our donor oocytes. This is something different from the market and has a significant impact on success rates. Also, for those who may consider oocyte donation treatment, this is already an advancement. So far, we have very low numbers because we need more data to educate AI for spindle qualification, but we have this as a goal.

correlation depends on the number of the oocytes we can get from the patient, sperm as well, because we were facing a few very challenging cases where we were creating so many eggs with multiple cycles and multiple egg collections for the patients, and then we saw very poor sperm, and patients chose to proceed with this very poor sperm. We couldn’t even do a FISH. It was a very high DNA fragmentation testicular sperm aspirated. This was one very unfortunate case where, from 7 eggs, we had no euploid. We had 3 relatively good, average-quality blastocysts, but that correlated with the impact of the sperm.

Even in this treatment, usually, we fertilise a little bit more oocytes for each patient—10 to 20% more—to replace with the best quality,  in terms of the AI response of the zygote, because we need proper morphology. Sometimes we have a number over what we need for the replacement, and patients may have, as a result of this treatment, some additional donor embryos. This couple also had one additional donor embryo, which also resulted in an aneuploid. This was unlikely to come from the donor and likely came from the sperm as well.

I would say that the number of oocytes, sperm parameters, sperm potential, and implantation potential play a role. This is the same answer as to how we correlate success rate for oocyte donation depending on patient age, there is no correlation if we can create a healthy euploid embryo using oocyte donation and then transfer this to whatever age the patient is because we know we can restore the endometrial function and the implantation potential for very late ages for women. We are still learning how to restore ovarian function, how to preserve it, and how to take care of it. So yes, it correlates with the number of eggs, quality of sperm, and implantation parameters, but it does not correlate with age or AMH or anything else.

The embryo has been reconstructed, and the PGT-A is not a deficiency—it is just a replacement. The embryo still has 24 pairs of chromosomes, and this is what we are going to test and what we recommend testing. This treatment is not gene editing, so if there is a genetic condition as an abnormality coming from the nuclear DNA, this treatment cannot treat this condition, but we can investigate all other genetic disorders, including the majority of mosaicism and other conditions that are not nuclear-related.

We want to be sure about the safety of this technology and the safety of the process for the patients, because transferring euploid embryos significantly reduces the risk of miscarriage and increases the probability of implantation. There is a lot of discussion around the reliability of PGT-A testing in different laboratories. We have a very advanced genetic laboratory that runs two different platforms for PGT-A testing, and then an expert evaluates the reading from the embryo. In many cases, mistakes come from results generated solely by the machine, or from contamination by external DNA (such as from the embryologist), which can lead to an incorrect abnormal embryo result. We trust the reliability of our genetic testing, which is why we recommend testing all embryos before transfer. It improves the chances and brings safety to this technology.

For the implantation potential, this embryo is not different compared to any other embryo, because genetically it will be related to the mother and to the father. Any embryo we transfer is immunologically only partially related to the patient, which can cause a specific immune reaction. We believe in immunological infertility. We have in our team a reproductive immunologist and an expert in this field. This is her speciality, and she has been doing this for years.

I have been using immunological protocols for years, including IVIG, intralipid, steroids, and other specific approaches. I have seen many patients referred for surrogacy who, once given proper immunological support, became successfully pregnant. Around 30% of unexplained infertility could shift to immunological infertility if properly tested and supported. Patients should be tested for immune system response, and if needed, we recommend introducing an immune protocol—not because of the MRT embryo, but because of the patient’s immune status.

Our immune system protects us, but by the age of 40, we have faced many viruses, bacteria, vaccines, and environmental factors. The immune system may become highly reactive, and in such cases, it can recognise the embryo as foreign. If a specific patient needs this support, we will introduce it as part of the implantation success strategy.

The majority of them were vitrified, but part of them were fresh. The challenge using fresh maternal eggs is around the fact that donors need to be selected. I cannot say that every day in the clinic we have a donor egg collection, but not every donor will be selected as a mitochondrial donation donor. That’s why we time these donors for the fresh egg retrieval when we are planning the group of patients. We may try to time the patients as well, but the majority of patients, because of their responses, will not respond as we expect them to.

70% yes, if we do it all in time with proper monitoring, but this doesn’t depend on us. This is biology. 30% will still not be synchronised. So it’s safe to vitrify the egg and then to use it, even if we know we need MRT for the spindle transfer.

The only cases where we will not recommend freezing the eggs are known cases of cryotolerance. If the patient knows and it’s proven from her previous history, and we have had a few cases like this, the cryotolerance phenomenon shows as vitrification not working. There is a tolerance to the cryoprotectant, and after freezing, these materials will not survive. This is very uncommon, but it may happen. Usually, because all our patients have multiple rounds of stimulation before, they have a chance to test this. This can be the only indication when we need to synchronise precisely.

This is a very interesting clinical case, and here the analysis of the PGT-A results will help to evaluate what the issue was. Likely, MRT will help, and this can be because of environmental changes. It will be hard to say this is because of the mitochondrial activity, because most likely the energy potential was proper, as so many embryos were developing and were finally developed properly and timely in terms of the morphological status.

But there was something else. Now we are testing several different molecules in different clinical trials. This takes years to start and to run, but it will be very interesting to learn about what else is playing a role in the aneuploidy. PGT-A testing from this case will help us to evaluate. We know specific genes and chromosomes which may be associated with nuclear DNA changes and those which are not associated. We need to read the PGT-A analysis, and then we will be able to comment precisely.

Not to our knowledge. We are not a clinical trial, so I need to mention that from all babies born, we are in touch with about 75 to 80% of the patients in constant communication. We always encourage patients to give us feedback. The majority of them give feedback about just the live birth, because this is part of the contract — we need this clinical efficiency. But we also encourage patients to be in touch for further development at three months, six months, one year, three years, and so on.

The majority of them are still in touch with us, but this is not an obligation because we are not running this as a clinical study. We may not have all the information about all babies, but I am sure that if there were an issue, we would know. For this 75 to 80%, we know that everything is perfectly well, and we do not see any health-related changes.

We always target our stimulation protocols to retrieve mature oocytes, because the stage of development of the cell should be equal when we are doing the reconstruction. This will bring us the best success in terms of the ploidy rate.

If we are receiving immature oocytes as a result of a properly managed stimulation cycle, and this immaturity is coming because of metabolic changes, trigger timing, or the optimisation or non-optimisation of the protocol, we would mature this egg in the lab.

Currently, we are having 78% of MI shifting to MII as the IVM process, and we have 34% of GVs shifting to MI and to MII and being properly fertilised. In the majority of cases, they need a few hours to mature in proper culture media. If they are not maturing, we need to understand that there is something we call cytoplasmic and nuclear maturation. If there is a question about cytoplasmic maturation, this is easy to solve. But if the question is with nuclear maturation, the external environment will not help to mature this, and those eggs will not result in embryos.

We target healthy mature oocytes with our protocols and controlled ovarian stimulation. If we receive immature eggs, we will do our best to mature them, but it depends on their inner cell potential whether they will mature and result in successful embryo development or not.

Except for the sperm, if we are talking about mature oocytes, not every spindle will be ideal in advanced maternal age patients. But if we have a spindle and it is properly formed, we would reconstruct and transfer. If this is a properly fertilised zygote, we will also reconstruct. We can evaluate only at the end of the development process.

I would correlate success with the number of eggs, but it should be a reasonable number. As I showed in my presentation, with more patients of advanced maternal age or very low diminished ovarian reserve, they usually want to target the maximum amount of eggs. From an administrative perspective, we have a package where the maximum amount is 15. Recently, many patients have tried to maximise their numbers up to 15.

However, from our clinical experience and from the data presented, sometimes even four eggs are enough. I understand the probabilities, so I would say 6, 8, or 10 is a very reasonable number for this age category and patient category to proceed with the process and target the next step, which is implantation potential. The final outcome is the live birth. So, the number is important, but we need to understand when to stop and move forward.

Because of the regulatory perspective in the UK, there is a licensed clinic in Newcastle performing treatment for mitochondrial disease carriers. If a patient is a mitochondrial disease carrier and this is proven, then the treatment can be performed in the UK.

For advanced maternal age or oocyte or embryo quality-related disorders, this technology can only be performed as an experimental treatment under the consent signed by the patient. We currently perform this in Albania and in Ukraine, as the regulatory field there allows experimental treatment under patient consent.

As you saw from one of the examples, FSH was one of the main predictive parameters of the response before we invented AMH, not so many years ago. You cannot imagine, but when I started to practice, we didn’t know what AMH is. We all correlated our outcomes with FSH, and it was said in all the books that when we see the FSH over 30, IVF will not work. We should not stimulate a patient, as that would have very low outcomes.

This is only partially true. In my practical experience, I see — and I showed — many of those patients, because their starting FSH is not how they develop their FSH. When we are injecting gonadotropins, the FSH will go up, and this is the communication between the hypothalamus, pituitary, and gonads. That’s why this correlation is important.

For some patients, we may see that they still may have preserved reserve with a high level of FSH. This FSH will have an impact on the quality and the morphology of the oocyte, and potentially embryo development. Even if the reserve is preserved, if the reserve is very low and the FSH is very high, this is already a combination of very low prognostic markers. Those patients will be very challenging in terms of their cycle response, ovarian stimulation, and the potential of producing a viable egg.

So, not only FSH, but FSH in combination with AMH, the antral follicle count, and also together with the regularity of the cycles.

Not only is DNA fragmentation important. It will be a combination of DNA fragmentation, concentration, motility, and morphology of the sperm. Based on all these parameters, we would define our approach.

We have very advanced methods for sperm selection, including the Piezo activation and the advanced ICSI with high magnification. We don’t do PICSI, but we do zygote selection and SpermChip. These are tests we can run on the sperm before selecting the proper one, not only in terms of morphology but also in terms of their functional characteristics.

The lab is very careful about sperm selection, as this is part of the success of the process, and they would advise. We do not have a cut-off criterion for DNA fragmentation because, as I said, this is not an individual parameter; this is a combination of them.

We use ICSI as a standard in our laboratory. There are some cases where it may not be related to the donor sperm, but to the membrane and the factors correlated with the oocyte. Sometimes IVF may work for fertilisation, but may result in a higher level of highly fragmented embryos. We cannot always predict these cases in advance, so in order to avoid them, we use ICSI as a standard method.

It is just a routine protocol, and there is no harm in doing ICSI compared to IVF. This is the protocol which is implemented. We can discuss the rationale behind why to do IVF, but there is a scientific explanation for why ICSI will be better and will bring no harm.

Yes, absolutely. We had many cases. They are quite common. We also had X-linked conditions, but we had for other disorders where the couple were both carriers, and we had to run the PGT-M cycle. Obviously, we all understand that this may decrease the number of potential viable embryos for transfer because we would need to choose diploids and then, among them, choose those that are not carriers. Here, the benefit would be if the patient could produce more eggs. There would be individualised recommendations based on the clinical parameters of how many eggs would be optimal before we continue with further treatment. In general, yes, it’s possible, and this is the same DNA sample as for PGT-A testing.

I am asking myself the same question for all those cases where we either ovulated prematurely, received no eggs, or received a very low follicular oocyte index. These are all disappointing points for both sides. Patients think it is disappointing only for them, but this is not true. For the clinical team, on one side, this is a clinical case we want to resolve, but on the other side, we are thinking about why we couldn’t prevent this and whether we could prevent it. I cannot say that all our transfers work.

I remember specifically one patient who got lost with our contact after two euploid embryo transfers after MRT, and neither was successful. She was prepared very well. She had uterine factors and systemic factors, also an immunological disorder, but during these 2 transfers, she had no more embryos. I don’t know what her future will be. Maybe in other clinics, many patients are lost, but for us, we try to keep in touch and we try to offer another solution.

As you have seen from our presentation, MRT is not the last choice. The last choice can be oocyte donation. Implantation failure is not the last choice. The last choice can be surrogacy. We still need to try to answer the questions about what is related to these implantation failures. Sometimes we have predictions, and those predictions can be related, as I said. You can go through the slides. It is as much as we do, and we do all this in advance.

Even if we do this all in advance, we have a patient population over 43 years old and our implantation rate is over 50%. The clinical live birth rate is over 50%, but it is still lower than 100% and we want to be at 100%. The most common cause— we would never transfer if we see that the endometrium is not optimal. We would rather cancel the cycle and start over again if we see that something is disturbing this preparation. Systemic disorders like the immune system are still quite a black box. We cannot always understand what is going on there. For the majority of cases, yes, but I believe that the testing we do could be way more detailed. We cannot do them all in advance because they are very expensive and not always needed.

As part of the recommendation for the MRT transfers, we do the majority of the most important ones. We do not do all possible, but those which should be included we have them. Systemic disorders like endocrine parameters—sometimes the TSH cannot be regulated, and even though the patient is on hormonal replacement, after transfer, it goes up to 4, 5, 8, and so on. This is something that happens despite having the medication.

We try to control all that can be related to chronic diseases as systemic diseases like rheumatoid arthritis, systemic immune disorders, but not only related to the NK cell levels—they can also play a role. Metabolic disorders—sometimes we can associate the factors of having no implantation with those disorders, and sometimes we cannot even evaluate them before the unsuccessful transfer. They may have been silent, and then we start to see them. We may also correlate these two together. The solution, as I said, is third-party reproduction. It is never the first choice, only for critical medical absolute indications. For others, we are trying our best to deliver the best success possible, but we are still not 100%—and no one is in fertility so far.

Being a woman, a mother of 2, and advanced maternal age over 40, as I said from my previous experience, I am always supporting innovations and I believe that this field—this is why I chose this field of IVF—because I understood that here it will be interesting and I am surrounded by people who are experts and also innovators. Without embryology, brilliant and the best in the world, I would not be able to do this. My part is first clinical in terms of receiving eggs, but then the heart is inside the lab, and then we are having a continuation of the process of implantation and further controls and development.

Regulations are very strict. This is something we cannot, as individuals, have an impact on. But I believe that as a professional society, who are believer in innovations and who learn every day, and a patient society, this is how MRT started to be legal many years ago in the UK. It was the desire of one individual patient, and she made this happen, and this is how it developed. Then there was the US, where regulators banned this, and they shifted us back for 10 years from innovations and practice. But now it’s like a new way.

I know many groups, and we are in touch with many clinical institutions and universities that are running projects now. The fact that Newcastle showed this paper—they didn’t do it yesterday, they did it during the last 8 years. Many treatments like this are performed under specific regulations, and this is still very hard because even to publish the data, we need to receive an ethical review, which is not easy. No one wants to take responsibility to make this possible as an individual, even if someone wishes to do this.

I believe in collaborations and the fact that together we may change this. I think this will be possible very soon because of all the developments we face in the fertility field, specifically. Sooner or later, we will be there, but so far it’s already available, and this is always the patient’s choice. This is reproductive autonomy. Patients travelled for medical tourism for reproductive options; they are travelling now, and this is how we can make this possible.