Ovarian Aging: Science and Impact on Fertility

Dr. Andres Reig:

Hello. I’m Dr. Andres Reig. Welcome back to FertiliPod, the podcast where we discuss current topics and the latest research in the field of reproduction with some of the world’s leading experts. Let’s get started. In today’s episode, we’re having coffee with Dr. Emre Seli. Dr. Seli is the chief scientific officer at IVI-RMA Global and is a world-renowned expert in this topic. Dr. Seli, thank you so much for joining us.

Dr. Emre Seli:

My pleasure.

Dr. Andres Reig:

You were, as we know, born and raised in Turkey. You went to medical school there. Tell us a little bit about yourself, about your journey from going to medical school, growing up in Turkey, coming to the US, and becoming the chief scientific officer at IVI-RMA.

Dr. Emre Seli:

Well, actually, it’s kind of a simple story. I finished medical school, got married, and when I was about to start my life in Turkey, but I had this desire to do research and combine it with medical practice, and an opportunity came along from Yale University, so I came to Yale in 1995 as a postdoctoral research fellow, and then I stayed as a resident, then as a fellow. Then I became a faculty and rose through the ranks, and became a professor in 2013. As I had initially intended, I combined seeing patients and teaching and doing research, and my laboratory was funded by NIH and many other grants.

Dr. Emre Seli:

Then as I became older, I developed an increasing fascination with aging, and also, I wanted to be able to do research that is more translational, because at Yale I was mentored, and then after that, my mentor was Joan Steitz, who is maybe not that well known in our field, but she is extremely well known as a scientist who received the Lasker Award recently. She’s a molecular biologist. So, working with her, and afterward, through my laboratory, I mainly used animal models, et cetera, and worked on a number of pathways, but none of my findings were really directly applicable to patient care, and I wanted to work on aging and do things that are translated to practice.

Dr. Emre Seli:

So, I got in touch with Dr. Richard Scott, who is a researcher and a founding partner of IVI-RMA Global, and we initiated a few projects on ovarian aging together, and after that, we realized that we work really well together, and we complement each other’s expertise, and at the end, we decided to do more and more research together. Then I took on the role of chief scientific officer at IVI-RMA Global. Right now, I work across continents, despite COVID-19, I guess, and we have a number of laboratories around the world where we do different types of research, and many of them are related to ovarian aging, which is the topic of today, some in Oxford in the United Kingdom, two laboratories in Spain, one large one in Valencia, and another one in Madrid, and of course, one of our biggest laboratory research centers is in New Jersey.

Dr. Andres Reig:

So, let’s talk a little bit about ovarian aging. We’ve worked on a couple of papers together on this, and I know firsthand that you are very interested and very, very knowledgeable about this topic. Clearly, you’re very passionate about ovarian aging research. Of the many, many subfields within reproductive medicine, why ovarian aging? Why this in particular?

Dr. Emre Seli:

Well, it’s my bias, and I think it is the single most interesting and difficult question in reproductive medicine, but in addition to that, it’s a very relevant question, and that part is, I think, indisputable because of the whole demographic and social and economic changes that happened to the females in the United States over the past five decades, and you can look at the numbers. We’ve recently analyzed this to see how we change and how fast it’s changed, and how drastic the change was, and if you compare, let’s say, just last year to 1970, which is not that long ago, it’s 50 years ago, the percent of women who received a bachelor’s degree annually doubled since 1970.

Dr. Emre Seli:

In 1900, less than one in five people who got bachelor’s degrees were females. Since 1990, more than 50% of bachelor’s degrees are obtained by women, and actually, since 2000, more than 55% of all bachelor’s degrees go to females. The same goes for master’s degrees. Again, less than one in five master’s degrees were earned by women in the 1900s, and since 1990, more than 50%. Of every 100 degrees obtained, more than half is by women and the same with doctorate degrees. Of course, this is associated with the delay in a lot of things related to reproduction, including marriage.

Dr. Emre Seli:

Basically, in 1970, more than 60% of women were married. This was down to 50% last year, and I guess the most drastic thing is the median age to get married, which was around 20, 21 in 1970, and it went up to almost 28 by 2018. Finally, the time when you have your first child or the time you deliver a baby also became later and later for women, the first time. So, all these things culminated in the fact that women are experiencing more and more infertility related to their age, and the research related to ovarian aging is becoming more and more relevant, and of course, clinical interventions related to ovarian aging are also becoming more. That’s why I care a lot about it. I think a lot of other people are caring about it, and most importantly, I think the emphasis on ovarian aging will increase with time, not decrease.

Dr. Andres Reig:

That’s actually something quite unique to the aging aspect of fertility, the idea that our social practices and our way of life really can have such a huge impact in fertility, whereas maybe other issues are more of a pathology in the classic sense of the word. Right?

Dr. Emre Seli:

Yes. I agree.

Dr. Andres Reig:

All in all, it doesn’t really sound all that different, though, from the many diseases that we count among the most serious, things like Alzheimer’s, some that are at least in part due to our increased life expectancy and the way we live. I think as a result of that, a lot of research has been conducted into the field of aging in general, in other cell lines, in other tissues. What would you say are the most important research avenues in the field of aging in general, not necessarily in the ovary, and some of the questions that are being asked and answered today about aging?

Dr. Emre Seli:

So, I agree with your comment. Before I respond to that, I agree with your comment regarding the importance of somatic aging research, and I remember hearing that if you cured all cancers, the longevity, the mean longevity increase in humans will be around five years, whereas at least in animal models if you affect aging pathways, you can increase longevity by 50%. I don’t know if you want to do that. I don’t know if you can financially afford increasing longevity by 50%, but that is how important the longevity pathways are. National Institute of Health has an aging institute where a lot of research is funded in this pathway, and there are a number of key targets regarding aging, and some of them involve the telomeres and methylome changes regarding aging, as well as mitochondria. I guess I would cite those three as important pathways that are targeted as either diagnostic or therapeutic approaches related to aging.

Dr. Andres Reig:

So, if you don’t mind, walk us through each of those in a little bit more detail. Let’s talk about perhaps the… One of the most well-known ideas of aging, it’s definitely the one that’s more common in the layperson media as well, the idea that aging is related to telomeres.

Dr. Emre Seli:

So, telomeres are just repetitive sequences that are present at the end of chromosomes, and they basically prevent chromosomes from being degraded or getting attached to others, basically getting broken down, and with time and through cell divisions, telomeres become shorter and shorter and shorter, and when they become short enough, they may lead to what’s call senescence, which the cells stop dividing and start dying, and then the aging ensues. Telomeres also tie into this idea of a clock that is sometimes cited in the context of aging, meaning that some people would propose that for the body or for a cell to know that it is aging, there should be something marking the time that passes. So, people suggested that through cell divisions, telomeres mark how much time has passed, and through that, cells know basically when to stop dividing and when to die.

Dr. Andres Reig:

Now, you also mentioned mitochondria and their role in aging.

Dr. Emre Seli:

Well, mitochondria is actually an interesting subject because as you know, and people listening to this know, mitochondria are responsible for generating energy, and they do generate energy by using oxygen, and as they use oxygen to generate energy, they make reactive oxygen species that are not good things, and we know that a reactive oxygen species could cause mutations. Now, why does that matter? It matters because mitochondria are unique in being organelles that have their own DNA.

Dr. Emre Seli:

So, a long, long time ago, around 60, 65 years ago, people proposed that the issues related to mitochondria being a source of reactive oxygen species and having their own DNA, and that DNA being necessary for efficient energy production, this whole complexity may cause aging. People proposed that for a cell to be healthy and young, it has to have an efficient energy metabolism, and they also proposed that efficient energy metabolisms require mitochondrial DNA to work in synchrony, in harmony with the nuclear DNA, which is much bigger and much more important, but mitochondrial DNA is also required for efficient energy production.

Dr. Emre Seli:

So, they said as oxygen is being used in mitochondria, and reactive oxygen species could cause mitochondrial DNA mutations, it is possible that as human beings or animals age, mitochondrial DNA becomes more and more dysfunctional, and leading to dysfunctional energy products and aging. So, this was a very well put hypothesis, and it was supported by the fact that when people later on generated animal models that have increased occurrence of mitochondrial DNA mutations, those animals age faster.

Dr. Emre Seli:

The reason why we are no longer that attached to this story is that when actually older human beings were assessed, we did not find mitochondrial DNA to have a high rate of mutations. So, although you could age an animal or human if you were mutating their mitochondrial DNA, it doesn’t seem to be a main pathway to cause aging. So, since then people started concentrating on other aspects of mitochondria, and one of them is called mitochondria stress response, which is very, very interesting in the sense that as we as humans can be stressed, our little organelles in cells can also be stressed, and mitochondria have its own stress system, and whenever the cell or mitochondria itself is stressed, it has an issue with folding proteins.

Dr. Emre Seli:

When mitochondria cannot fold proteins, they tend to initiate certain pathways to take care of the problem. If they can’t take care of the problem, the cell basically commits suicide through apoptosis, and people found that at least in lower animal models when the mitochondria stress response is abnormal, it can cause accelerated aging. So, this is an avenue of research for general aging, as well as reproductive aging. Also, another aspect of mitochondria is that they tend to fuse and divide, so sometimes might come together and attach to each other. That’s called fusion, and then when they divide it’s called fission, and when those mechanisms are affected, it could also cause changes associated with accelerated aging.

Dr. Andres Reig:

So, in trying to find a way to understand aging, we found another way we can age that doesn’t affect us, and then we found other things that do affect us. That’s science, I guess. Right?

Dr. Emre Seli:

It is.

Dr. Andres Reig:

Just trying to find something, and finding something completely different.

Dr. Emre Seli:

Yeah, absolutely. Absolutely. If one doesn’t work, we go and look for something else. But there’s a lot of people who believe that there has to be something related to mitochondria one way or another, and there’s a lot of animal models that support it. How important it is for human somatic aging remains to be seen.

Dr. Andres Reig:

The last thing you had mentioned was the role of the methylome in aging.

Dr. Emre Seli:

Yeah. I mean, methylome is more of a clock concept. Again, people are looking for something that records time. Now, of course, I really buy into the clock concept, but you could also argue against that. I was talking to a friend of mine recently, but he said, «Well, I have a refrigerator, and it works, it works, it works, and one day it stops working because it’s old, and it’s not that it has a clock in it that tells you.» So, that’s another view. Maybe it’s just that you go, you go, and then you give up, but it kind of makes more sense that because we all seem to be aging at the same speed, most of us without major diseases, except for people who have major cancers, et cetera, most of the healthy people seem to be aging with the same speed.

Dr. Emre Seli:

It kind of makes you feel like there is a clock in it, and then what people did is they looked at methylome because if you take away mutations, which do not seem to happen, it’s not like we’re mutating the time under the sun or anything, so our DNAs seem to be mostly intact for those people who age healthily, then there needs to be a non-DNA mutation-related recording system, and a good candidate for it is the epigenetic recording, which means you’re making a mark around the DNA, but you’re not changing the DNA. For that people use methylome, and methylation of CPG islands in the DNA is an epigenetic regular sort of mechanism.

Dr. Emre Seli:

As you know, epigenetics is a way we use in our bodies to differentiate cells. For example, your eyes and your skin have the same DNA, but your eyes have a very different function than your skin, so that is achieved not by mutations, but through the opening and closing of gates in the DNA to determine function. Similarly, people said methylation of CPG islands could mark the passing time, and it turned out it’s actually true. People developed clocks. One of them that is widely accepted is the Horvath clock, and Horvath is a mathematician who basically sat down, or was the physician who sat down and analyzed 100,000 methylomes that are available from human samples, and then he developed a clock based on only 353 sites among millions that can predict healthy people’s age.

Dr. Emre Seli:

So, basically, you can take somebody’s blood and analyze the methylation status of blood cells and, say, guess pretty accurately how old they are. Of course, you could ask them how old they are, but in this specific situation, you can use methylome analysis, and this is an important aspect of aging diagnostics and aging research because then, of course, whenever you establish a clock, then you become able to assess mechanisms that can accelerate that clock. So, he and others wrote out this concept, age acceleration, things that make the clock run faster. So, I think that is a fascinating avenue of research. Of course, there are other metabolism-related pathways that are pursued, but we can’t discuss all of them here.

Dr. Andres Reig:

So, it looks like there’s… I mean, we’ve talked about mitochondria, telomeres, and methylome. There’s definitely a lot of research and a lot of resources being poured into understanding how and why we age, and this is mostly being done, as far as my understanding goes, in terms of somatic cells, but your field of interest is the aging of the ovaries specifically. How much of what we know about somatic cells applies to ovarian aging as well?

Dr. Emre Seli:

I mean, that is obviously the most important question for us. How much can we borrow, I don’t want to say steal, but borrow from the great researchers that committed their lives to aging, per se, and how much of their information is applicable to us? Of course, we don’t know, really. We are investigating, but we don’t necessarily know what the mechanism of ovarian aging is, or what mechanisms are. We don’t know if it’s the same or different from the mechanisms that regulate aging in other tissues. We don’t know if ovarian aging can be stopped or delayed, can it be reversed, and of course, a lot of the things that were implicated in somatic aging are being pursued also regarding ovarian aging. This includes, of course, the other things that I just explained to you about the telomeres and methylome, et cetera.

Dr. Andres Reig:

Why do you think it’s so difficult to study aging in the ovaries specifically? What are some of the, would you say, the biggest challenges in making progress in our understanding of ovarian aging specifically?

Dr. Emre Seli:

So, it is primarily because there is not a very good animal model for human ovarian aging. Whatever the initial mechanisms that may cause the aging, the way we perceive infertility or decreased fertility, especially with human ovarian aging, is by increased aneuploidy, abnormal chromosome segregation into embryos, and there is not a good animal model for this. For those of us who use animal models and continues to use, and I still have my own animal laboratory at Yale where we do ovarian aging research using mouse models, at least, there are issues regarding this, but because of the way you approach ovarian aging research in animals is that you come up with a hypothesis, and then you say, «Such-and-such pathway could be implicated, could be causing ovarian aging,» and then you generally affect that pathway.

Dr. Emre Seli:

You may generate a knockout model. You may make a mouse with that knockout, and then prove that you were right, because when you knock that gene out, the mouse becomes infertile because it loses eggs, or their egg becomes older, et cetera. However, how much this applies to real-life scenarios is debatable. So, the clinical relevance of those findings is unclear. I’m not saying this research is not valuable. I personally am very committed to doing that research. All I’m saying is that it is unlikely to have an immediate impact on the health of our patients.

Dr. Andres Reig:

It’s not very different from what you were mentioning earlier from some of the mitochondrial research that-

Dr. Emre Seli:

Absolutely.

Dr. Andres Reig:

… then is not really… When you actually analyze older people, they don’t actually have those mutations.

Dr. Emre Seli:

Absolutely. Absolutely. That’s a very, very good observation. It is. It is. Again, I guess people wouldn’t mind me saying it because I’m also doing it. I’m one of them, and I’m not criticizing them. I’m one of them. I believe in that research because we also need to… Even if you don’t go to certain places, you need a world map. Right?

Dr. Andres Reig:

Mm-hmm (affirmative).

Dr. Emre Seli:

A map had to be made. So, I’m all for mapping. However, we have to understand the limitations of it, and also, there are additional challenges regarding human ovarian aging research, and one of them is, of course, the difficulty regarding getting funding to do human embryo research. As you know, federal funding is not available for research that involves human embryos, so a lot of researchers who are in academia or who are very talented and well-trained investigators are unable to actually do experiments on what they should be doing it on. They cannot use human embryos. They cannot even touch embryos. They cannot make actually a phone call using federal funding regarding embryo research.

Dr. Emre Seli:

The final thing is something I became aware of after I started working at IVI-RMA, a final challenge. Coming from animal research, again, I’m used to having a theory and testing my theory about a gene or about a pathway by just knocking it out, knocking down the pathway, and when you do this all-or-none kind of phenomenon, the impact is the effect size is big. There’s a huge effect, and then there is never an issue finding a statistical significance. If that pathway matters, it’s so easy to prove. I mean, if you’re right, it’s easy to prove in an animal model. However, when you go to real human females, it’s much more difficult because you can’t, first of all, take them and knock out their genes, and secondly, we, the reproductive aging researchers, are at a disadvantage because what we call young in an IVF center is a 32-year-old woman, and what we call old is 44.

Dr. Emre Seli:

So, it’s basically 12 years difference, whereas a somatic aging researcher could compare a 20-year-old to an 80-year-old. But in an IVF center, you have the 32-year-old and the 44-year-old, which is not that different. So, the effect size is not big, and when you add to that all these compounding factors, were they smoking, were they obese or not, et cetera, all these things that happen, and you also have to add the male somewhere around there, although we focus much less on the male. So, it is not an easy experimental system due to the small effect size. Now, in order to deal with this, you have to have extremely robust experimental systems, which we are trying to focus on.

Dr. Andres Reig:

In coming back to the specific mechanisms, you had mentioned earlier the telomeres, mitochondria, methylome. How do those apply to ovarian aging in particular? Since it’s so difficult to study the ovary in particular, can we just extrapolate what we know about aging in other tissues and apply that to the ovary?

Dr. Emre Seli:

Yeah. I mean, I can just focus on, as I said, the three main pathways that I mentioned. Again, there are many different pathways that are implicated in aging. Some of them involve metabolism, et cetera, but for example, telomere, David Keith, who used to be an assistant professor at Yale when I arrived in 1995, and then later went to Brown and New York University, but became a chair, he did very high-quality research on the role of telomere shortening and ovarian aging, and we also at RMA, both in Madrid and New York, develop systems to robust the test telomere length.

Dr. Emre Seli:

Elisa Varela and Juan García-Velasco in Madrid use confocal microscopy with fish methods, and we have a pretty robust QPCR system, and we did find the differences in telomere length associated with ovarian aging. Interestingly, we found that cumulus cell telomeres tend to be long, meaning cumulus cells seem to remain younger compared to the other somatic cells, and we did not find a major change in the telomere length associated with women who had insufficient reserve or when aging, et cetera, but again, David Keith’s work suggests that there could be embryo-related changes in the telomere.

Dr. Emre Seli:

As far as a mitochondria goes, there is work from a number of researchers regarding the association of mitochondria function and reproductive aging. Bob Casper’s research group had shown the role of CoQ10 in animal models. They initiated a clinical study, which did show some benefit in activating mitochondrial function. We did find that mitochondrial stress response or mitochondrial fusion, fission abnormalities in animal models is associated with a diminished ovarian reserve picture.

Dr. Emre Seli:

Some other researchers found that mitochondrial DNA copy number as a marker is associated with embryo viability in the initial two studies that are the most impressive ones, some of them are coming from previous or current IVI members, show that increased mitochondrial DNA copy number is associated with decreased viability of embryos. Since then, there’s been a number of studies that argue that this may not be true in every environment. This includes us. We did challenge this idea, and I think it may be associated with the stability of the IVF laboratory, meaning that… I don’t know how to say this.

Dr. Emre Seli:

For example, TSH, if you’re checking TSH in people, you can say high TSH is bad, and that would be correct, but high TSH within the normal range is not bad. So, maybe in IVF laboratories where there’s a lot of variability in the environment, you may be generating embryos that are really immensely stressed. Therefore, they generate extremely high mitochondrial DNA copy numbers, which then is associated with lower implantation potential, whereas in maybe more stable laboratories, it may be less predictive.

Dr. Emre Seli:

So, that is where we are, I think, with the mitochondrial assessment. Of course, mitochondrial function or lack of mitochondrial function has been targeted through mitochondrial replacement in this, which did not really pan out as people hoped. Finally, methylome research, that is interesting… We really missed a lot of time and effort and resources for that research, and we found that actually, again, similar to what we found in telomeres, cumulus cells seem to have a methylome age that is extremely young compared to white blood cells.

Dr. Emre Seli:

So, a woman who is 33 years old, if you try to guess their age from their cumulus cell methylome, you would find that you would think they’re 10 years old. So, cumulus cells seem to remain young, both from a telomere and methylome aspect, but we did find that white blood cells of women who have diminished ovarian reserve seem to develop an older pattern. So, it is possible that overall aging is associated with the fertility aspect of women, but this is, of course, at very early stages, and I think a lot of other investigators will be pursuing this as a research opportunity.

Dr. Andres Reig:

So, some of these discrepancies between the findings in somatic cells and those in ovarian aging, as well as the gaps between the two, bring us back a little bit to the reason why this matters to begin with, this idea of pushing back the clock, of slowing downtime to avoid age-related infertility, and to some degree, I would say we’ve been pretty successful as a field of reproductive medication in helping women who, for whatever reason, choose to delay childbearing, things like egg donation, cryopreservation, other techniques of that nature. Now, before we go into some of the more recent stuff that is currently happening, you know I like to ask a little bit about the history and the background stories. Tell us a little bit about how we got here. How has what we know about ovarian aging evolved to get us to where we are today?

Dr. Emre Seli:

I think for a long time people knew that as women become older, they are less likely to achieve a live birth. From a research perspective, the realization of a decreased oocyte number came from ovarian histology studies where people took whole ovaries and counted follicles, and I think Roger Gosden’s work should be known there. Around 2004, 2005, there were some critical studies challenging our acceptance that women are born with a finite number of eggs, and they don’t make any new eggs. These are challenged by Joshua Johnson, Jonathan Tilly, whose work suggested that mammalians may be generating new eggs from stem cells.

Dr. Emre Seli:

There’s an ongoing debate about this, and it’s a long topic, I guess, for another podcast. We could invite them to speak about it, and the jury’s still out. There are also… If we talk about the history of associated reproduction within the context of ovarian aging and what we are now able to do to address ovarian aging, I guess we have to go to the landmark things like the first IVF in 1978 by Steptoe and Edwards, and the first embryo cryopreservation published by Alan Trounson in Australia, who was a runner-up in trying to do the first IVF, but he did the first embryo cryo. Then some people could be surprised to know that the first oocyte cryo paper was in 1986 by Chang, although it took a long, long time to perfect it afterward, and of course, the first preimplantation genetic testing, which we now call PGT-A, by Handyside in 1990.

Dr. Emre Seli:

Those are all interventions that today we use either to achieve pregnancy or preserve fertility. I should also mention that oocyte cryopreservation and the perfection of oocyte cryopreservation was partially thanks to strong work from Ana Cobo from IVI Valencia. Her work, among others, was one of the key things that bring oocyte cryopreservation to what you could call mainstream, and establish the significant success that can be achieved through oocyte cryopreservation, but also the safety of the procedure. Similarly, IVI and RMA made significant contributions to, of course, the perfection of egg donation and embryo cryopreservation. Of course, there are other recent brave attempts that target ovarian aging and trying to reverse it or treat it, but I’m not sure they’re mainstream right now.

Dr. Andres Reig:

Fair enough. We’ll talk about those. We’ve come a long way in the understanding of ovarian aging and how it works, and there’s still a long way to go. We’ve also come up with some strategies, as we just explained, to kind of mitigate or compensate the effects of aging, but of course, these have their shortcomings, that you need to freeze when you’re younger, you need to use donor gametes, and so forth. So, the kind of the Holy Grail would be to be able to reverse ovarian aging, or at least be able to obtain some more eggs from these older ovaries. I know this is your passion, and you’re currently involved in some of the research in this area. What can you tell us about some of those things that are currently happening in the field of ovarian, I guess a term is up for debate, but the field of ovarian rejuvenation or reactivation, if you will?

Dr. Emre Seli:

I guess I’ll go with the rule of threes here again. We reviewed three pathways for a mechanism, and here I think we need to mention the attempts on a decreasing aneuploidy, increasing fertility in women who do not make healthy eggs by replacing mitochondria obtained from their own stem cells. This was attempted as a clinical treatment, and studies with historical controls seemed to show benefit, but actually, we did perform a randomized controlled trial at IVI Valencia, and we can, I think, confidently say that mitochondria replacement is not helping.

Dr. Emre Seli:

I don’t mind… Sometimes one study shows something, and then we do a more robust, and you show that it doesn’t benefit it. It’s worth thinking about it, though, and because replacing a mitochondria into the eggs for a, let’s say, a 42-year-old woman who produced a metaphase II egg, and hoping that you will benefit from it, I guess it would be similar to taking a very, very old house and painting its walls. You’re not really changing the content of what makes that house old, and it is unlikely that it will be extremely successful. So, despite of my ongoing research on mitochondria, I was not very hopeful that replacing mitochondria would help, and I’m sorry that it actually did not.

Dr. Emre Seli:

So, as far as the interventions regarding ovarian, call it ovarian rejuvenation or the term I would prefer is follicle reactivation or ovarian activation, there’s been a number of attempts. I think if you go from chronological order, we should first mention the work of Aaron Hsueh from Stanford where he basically targeted the Hippo pathway in order to activate cell division and follicle division, and it was kind of interesting. I don’t know the demographics of people who would listen to this podcast, but when I was young, when we did not have iPhones and computers and the internet and streaming and all that stuff, we used to hang out on the street, basically, gather after lunch or dinner with our friends.

Dr. Emre Seli:

Some of my friends used to catch animals, lizards, et cetera. This is in Turkey I’m talking about. You would see that if a lizard would lose part of its tail, it could regrow, and actually, that is the Hippo pathway in action right there, because when the active filaments are cut, it activates a pathway that is conserved in animals of different levels, including lizards and human, and that can be used to activate follicles. What Hsueh and his group did, they cut cortical strips from ovaries of women who had premature ovarian insufficiency, and cut those into small pieces, and they also did a pathway activation through some targeting the AKT pathway, and they were able to achieve pregnancies and activate follicles.

Dr. Emre Seli:

The key thing to understand here is that you need to have follicles to activate follicles. So, they do not claim to create new follicles, but they say that using Hippo pathway activation by cutting active filaments, they were able to activate follicles in some subgroups of women who had actual follicles. So, after that came the work of Sonia [Herraiz 00:40:22] and Antonio Pellicer, who basically took a completely different approach and tried to basically mobilize stem cells from the bone marrow by using appropriate medications, and then collected blood, isolated the stem cells, and then injected those stem cells into the ovaries, through the ovarian artery.

Dr. Emre Seli:

Similarly, they were able to achieve activation of ovaries in some women. In this case, I believe it was the insufficient reserve patients or poor ovarian response, POR patients, not necessarily ovarian failure patients, and of course, the response was variable. Of course, there was a limited number of women who responded. It was not all of them, but some did. More recently, people have been applying platelet-rich plasma, which you can obtain a woman’s own autologous blood. Basically, you collect the blood and you isolate the white blood cells and red blood cells, and then you take the plasma that is rich in platelets, which also has a lot of growth factors in it, and then people start injecting this into the ovaries.

Dr. Emre Seli:

We also collaborated with some of our colleagues in Istanbul, Turkey, and initial studies seemed to show that at least some of the women do benefit. The reason to mention all these three approaches in the same breath, I guess, is although the approaches seem very difficult, they’re all doing the same thing. Basically, in all these women there seems to be a significant decrease in ovarian reserves so that they themselves, on their own, are unable to pull a follicle to be activated and to generate a fertile egg. So, what they do is, all these interventions, some will activate the egg or the cells around the egg, or the whole environment, to help that follicle grow and bring out an egg.

Dr. Emre Seli:

Now, what we find, although it may sound very simple, that when you’re old, you’re old, meaning giving these medications is unlikely to increase euploidy rates. So, if you are activating follicles in a woman who is 44-year-old, it’s quite likely that you may end up with an egg. But these interventions, at least in some women, seem to benefit. Now, of course, I should emphasize that this should not be applied to the patients. It should only be on the research protocols, and that has been our model also in RMA, and we are conducting a randomized clinical trial for PRP use.

Dr. Emre Seli:

We did not feel that our patients in the United States would be willing to participate in a randomized clinical trial regarding the surgery associated with the Hippo pathway. But PRP is easy enough for our patients, and we are conducting a randomized clinical trial, and we are interested in the results. We will see. We’ll see whether it helps or not because it is also possible that these people could just be responding intermittently, and that all these studies, maybe they’re just finding this random activation.

Dr. Emre Seli:

I should also mention when we discuss experimental procedures, I would also like to mention the work of Nuno Costa-Borges and his colleagues who are doing really exciting work in basically taking the DNA from an older egg and putting it into a younger egg so that you change the environment, and he seems to find pretty exciting results, and again, that also has to be tested in a larger context in multiple centers. So, those are, I think, the things I would highlight. I’m sure there are others that I didn’t mention or I forgot or I don’t know about, but there’s a lot of creative work going on, and we’ll see how it pans out.

Dr. Andres Reig:

Truly, truly cutting edge, very exciting. What do you see as the future of this field? How do you think we’ll see… What will you think will be our view or our understanding of ovarian aging 10, 20 years from now?

Dr. Emre Seli:

Well, as my very good friend Piero Rinaldo, who’s also a researcher in a way in biology and a professor at [UCSF 00:44:54], would say that there is market pressure to address this issue. I mean, there is a huge interest, and if there is something to be discovered, it will be discovered, because this is really the Holy Grail for productive research today. Now, I’m not necessarily an optimist by nature, so I don’t know when it will happen, and despite the fact that I’m excited about all new ideas, it will take us a lot of data to convince us to apply this as mainstream to our patients.

Dr. Emre Seli:

But I do believe, first of all, if nothing else, we would have better diagnostics for ovarian aging, and to detect women who are likely to age faster than others. That I’m quite sure in 10 or 20 years, probably 10 more than 20, and then I’m quite sure that our fertility preservation approaches in embryo cryopreservation, oocyte cryopreservation, and ovarian tissue cryopreservation, and others will become even better. As far as reversing ovarian aging, that will be more of a challenge, and I think it will go probably hand-in-hand with our success in reversing somatic aging, which is also a very, very active area of research.

Dr. Andres Reig:

I want to ask you one last question. If you could ask for anything related to this field of research, you have one wish, what would you want? Would it be endless funding, the answer to a particularly important question, the ability to do a specific experiment that you’ve always wanted to do?

Dr. Emre Seli:

Well, actually, when I joined IVI-RMA as the chief scientific officer, when we were talking with Dr. Pellicer, Antonio Pellicer, and Richard Scott, I was saying that we are out of excuses now because we can ask any question we want now at IVI-RMA. We have access to samples, and actually, we do have funding. So, the only thing that limits us is the technology that’s available, the accuracy of technologies that are available, and also our creativity. So, if I can ask for anything, I would hope that the techniques which we use, such as ATAC-seq or next-gen seq-based methylome analysis, is to become more efficient, because that happens outside of our reach, and that would allow us to really ask questions in a more reliable manner, and answer them. That is the only thing, I think, that limits us. The rest, I think we’ve kind of got it.

Dr. Andres Reig:

Fair enough. Fair enough. Well, thank you so much. This has been amazing, to talk to you for the last hour or so.

Dr. Emre Seli:

It’s my pleasure. Thank you for having me.

Dr. Andres Reig:

This has been another episode of FertiliPod by IVI-RMA. Thank you so much for listening. Tune in next week for more research and topic discussions, and all things reproductive medicine. See you next week.