Members Webinar

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Speaker 1
00:38 – 00:50
Yes, good evening everyone. So I’m Bart van der Schure, I’m the president of the Belgian Association for the Study of Obesity and it’s my pleasure to welcome you to the first Early Career Network webinar.

Speaker 2
00:51 – 02:15
So Basel was founded back in the 80s and the idea was to bring together researchers that who are doing research in the field of obesity. And the reason for that was that at the time, obesity was still not fully viewed as a disease. And often people in the field felt a bit lonely. So they felt the need to associate themselves. After that, Basel became a bit larger and we also included everybody who was giving care to people living with obesity. So all healthcare professionals involved in the care for people living with obesity, we try to give them a platform and to give them opportunities to talk to each other and to learn from each other. And that’s exactly why we have these webinars and especially the young ones, of course, we want to reach because it’s with the right attitude but also with the right knowledge that we will be able to better care for our patients. Basel also has an obesity platform Belgium which is a more policy oriented part of Basel to shape how the government is treating people living with obesity and is designing care paths for people who are living with the disease. And it also has a patient branch which is called Infobase and they are trying to give patients a safe space to talk about their disease

Speaker 3
02:15 – 02:18
and they come together once a month in Leuven.

Speaker 2
02:19 – 03:09
So that’s it from me. I hope that you will find this first webinar of the European, of the Early Career Network useful. But I really would like all of you to become a member of Basel. It’s extremely cheap, it’s deductible from tax and it allows you to come to our meetings, to participate in our meetings, to also send abstracts for our meetings where you will meet all those that are involved in obesity care in Belgium. But further on, it also gives you the opportunity to go to the European Association for the Study of Obesity Network events, the Congresses at the Reduced Fair and also the World Obesity Federation. So that’s it from me and I’ll now hand the word to Nela.

Speaker 4
03:11 – 04:16
So thank you Bart, welcome everybody and before we start with our first webinar I would really like to briefly introduce the Early Career Network of the Basel. We have recently created this network to support young researchers, clinicians and professionals within the research area of obesity or the clinical practice and our goal is to provide a platform where we can network, collaborate and provide career development for those and we want to highlight the voices especially of those early career members. This is our first webinar, our first official activity. There are a lot of other activities that will follow and next webinar is already planned for in February. Hopefully you will do a networking event soon and we invite whether you’re a PhD student, a postdoc, a young clinician or just starting your career in the field to join you can find information on our website or please reach out. So I will now give the words to Imke who will introduce our first speaker.

Speaker 5
04:22 – 05:12
Good evening everyone. So I’m going to introduce Dr. Eline Lieves. She’s an assistant professor in exercise physiology and sport nutrition at Kent University. Her research focuses on skeletal muscle physiology, but also muscle fiber typology and the link with sports and metabolic diseases. She has worked with advanced methods such as single fiber transtrictomics and beyond her academic work, she’s also a co-author of a book, De Beweegreden, for bringing science to the general public. And today she will present her research and her insights of muscle fiber typology, its heterogeneity, and how it’s linked to the development of cardiometabolic diseases such as obesity. So Aileen, I give the word to you.

Speaker 6
05:15 – 46:31
– Good evening, everyone. Thank you for having me. I’m happy to present to you the research line that I just started off, which is called the muscle monitor, in which I will look into the importance of muscle in cardiometabolic diseases. And I’ll start with a sprinter. Have you ever wondered what a sprinter and a person living with cardiometabolic disease have in common? You might not really think about their physiology, But if you look closer at the body, you can see that they share the muscles because all of us have almost 40% of muscles and these muscles are important. They are important for sports, that’s quite obvious, they help you move, but they are also very important for cardiometabolic diseases. For example, when you think about insulin resistance, You can see that before you eat, there is a certain amount of glucose in your blood vessels. If you eat, it raises. However, you don’t want that glucose to be too high in your blood vessels for too long. So you transfer it via hormones like insulin into either your liver or your fat stores, or the biggest part of this glucose goes to your muscle. Now, these muscles are important, they are the biggest storage of those glucose. And if you’re eating, if you’re eating more sugar, for example, you will stress this insulin system a little bit more and you will ask your fat stores, your liver and your muscles to become bigger, to have more glucose storage. However, after a while, if the storage of your muscles is full, there is no more space more glucose because either you don’t have a lot of muscle or you’re not using the glucose in your muscles, there becomes or there seems to be a problem in which you are no longer listening to the sign of insulin and you become diabetic. So muscles are very important and not only the muscles in total are very important but also when you look closer into the muscle the heterogeneity in these muscle fibers is very important. In your muscle, we have two types of muscle fibers, roughly divided into slow fibers and fast fibers. And these slow and fast fibers have different characteristics, which are both interesting for sports. And I devoted my PhD on that topic, but which also have their effects or their characteristics, which are very interesting for cardiometabolic disease like diabetes, but also obesity. For example, if you would look at the characteristics of slow and fast fibers, there is a different kind of contraction velocity. The fast fibers can contract faster, they have a higher contraction velocity. They can produce a higher power, they have a different energy metabolism. The fast ones are used to use the anaerobic system more often while the slow ones oxidize their energy more easily. The fast ones have a higher energy cost, so when they are doing exercise, they are using much more energy for the same kind of exercise. And these fast ones are less fatigue resistant, while the slow ones are much more fatigue resistant. Due to these different properties, this muscle fiber type composition is important for sports. And more precisely, if you have a lot of slow fibers, you’re more prone to be able to excel in prolonged low-intensity exercises, like marathons, let’s say, while the fast fibers are really needed for high-intensity and maximal efforts, like, for example, BMX or sprint type of activities. Now, this distinction in between slow and fast fibers is mostly known by practitioners in sports fields. However, these slow and fast fibers have also very interesting characteristics which differentiate them and which could be related to the health. Now, what’s very interesting in human is that most of us have almost 50% slow and fast fibers in their vastus lateralis, which is a muscle in the upper leg. However, there are some people which have a predominance of slow fibers and others which have a predominance of fast fibers. And at this slide, you can see the Gaussian distribution. Most of us will have a mean, a mediate, will be somewhere in between. We’ll have 50% of both. Some will have up to 20% fast, and others will have up to 20% slow fibers. So they will have a predominance. And this is very important for, for example, acceleration in sports. As for example, sprint athletes have a lot of fast fibers, while endurance athletes have been shown to have a lot of slow fibers or a low amount of these fast fibers. Now, as I told you before, these slow and fast fibers not only have characteristics that are very important for sports, they also have different characteristics which can relate to cardiometabolic disease. For example, slow fibers are shown to have bigger or more capillaries, They are better perfused. They have a higher fat oxidation. They are able to use fats in a much better way than fast fibers. They are more sensitive to insulin when compared to fast fibers. They are more metabolically flexible. And therefore, we hypothesize that if you have a lot of slow fibers, you might have a lower chance to become metabolically dysfunctional. Well, if you have a lot of fast fibers, you might have a bigger chance to have a metabolic disease later in life. Now, if this is indeed the case, then we would probably also see it in former athletes. And if you look at the chance of endurance athletes to develop, for example, diabetes, you can see that the endurance athletes have a lower chance of having diabetes in their life when compared to a normal control group who doesn’t do sports or specific sports. While people with a lot of fast fibers, the power sports, the sprinters amongst us, which are presumed to have a lot of fast fibers, don’t seem to have that advantage. So it seems that even in supporters that people with a lot of fast fibers might have a disadvantage when it comes to cardiometabolic diseases. Moreover, if we then look into obese subjects, but also in subjects with type 2 diabetes, we see that on average these obese and these diabetic subjects have a faster muscle typology. So they seem to have faster muscles when compared to controls. And that is very interesting because this is what sprinters and obese and diabetic subjects share. They share the bigger amount of fast fibers. Now, as there is a big heterogeneity in this muscle fiber type composition in the human population. For example, if we have 10 persons in front of us, 4 will have an almost equal amount, while 3 will have a faster typology, and 3 will have a slower typology. This muscle fiber type composition is very interesting. And we are already measuring this muscle fiber type composition in sports, as it could for example help us in talent identification, but we also think that it could help us in finding people at risk. So now we know that these muscle fibers are important. They seem to be important both for sports as well as for for health or for risk in developing cardiometabolic disease, but then obviously the question comes how can we measure this muscle fiber type composition. Well, this is mostly done in an invasive way using a biopsy needle. It’s quite big, it’s almost the size of my finger and I have a little video in the presentation in which you will see it being used on my leg. I’m still here and nothing’s wrong with me but if you don’t like needles or bloods please look away for a second because it might be quite devastating to see. So what really happens is we put the needle into the leg. I had some local anesthetics for that and then we cut a little piece of muscle out of the leg. We take the piece of muscle out and then we analyze your muscle fiber type composition. What we then get is some muscle pieces, we call it a biopsy, and we make some cross-sections of that biopsy. We make a slice, a little slice of that bigger piece of muscle. We then add some antibodies to that slice and in that way we can then visualize those slow and and those fast fibers, and we can count or estimate your muscle fiber type composition. Either the number, how many slow and fast fibers do you have in your little slice, or the area is important. Now, if you would ask, and we did that to coaches, we asked them, do you think your athletes would want to have a biopsy? only 18% things they would be willing to do so. And therefore we invented a non-invasive technique to estimate this muscle fiber type composition using an MRI scan. So we are no longer in need to use that biopsy needle, although we still do for some research purposes, but we can do it via a non-invasive technique from which I will show you a video. Well, what we do is we get at least, but also normal people into our scanner. We place a foxhole around their calf. We first make an image of their calf using MRI, and we then use spectroscopy in order to look at the metabolic environment, which is present in the muscle. Step by step, we place a person into our scanner, we make an image of the calf, we make or we put a little box, an imaginary box into that calf, and in that box, we are interested in the metabolic environment which is present over there. More precisely, we’re interested in carnizine. And why in carnizine? Because carnizine has been shown to be twice as abundant in fast fibers when compared to slow fibers. So if I would put you into the scanner and I see that you will have a lot of carnizine, that gives me the idea that you will have a fast typology. We have obviously validated this technique against the gold standard, which I’ve previously shown you via these biopsies. Now we then have a carnizine value. And of course, that’s not really interesting for you just to know your carnizine value. So what do we do with that? We then make a Z-score out of that, meaning if you have a Z-score of zero, you will have an almost equal amount of carnizine, but also an equal amount of slow and fast fibers as the general population. Well, if you have a higher Z-score, you will have a faster typology. If you have a lower Z-score, you will have a slower typology. A question that then pops up, okay, the muscle fiber type composition is important. We can measure it either via an invasive way or via a non-invasive way. What about the, it’s genetically determined? Is it genetically determined or can it be changed by the environment? Well, if you look at identical twins and you measure their muscle fiber type composition, you can see that they’re very close to the line of identity, indicating that there is a high genetically determined background of this muscle fiber type composition. However, if you look at non-identical twins, they are a little bit further from the line, indicating that genes are indeed important for this muscle fiber type composition. This doesn’t mean that the environment is not important. For example, at the moment we have seen that people with diabetes or with obesity have a faster typology, but it’s still unclear if the disease caused a difference in the muscle fiber type composition, or if these people were born with a different muscle fiber type composition, a faster typology, and they therefore had a bigger risk to develop those diseases. But in general, the biggest amount of these muscle fiber type compositions will be genetically determined. A second question that’s also popping up, we are, for example, measuring the muscle fiber type composition with a biopsy in the upper leg, while with our scanning technique, we are measuring the lower leg. If you measure one leg, does that then tell you something about your whole body? just tell you something about other muscles in your body. And very interesting to know is that the muscle fiber type composition differentiates or is different in between, for example, lower muscles of the lower part of the body or of the upper part of the body. The upper part is normally a little bit faster. The lower part is somewhat slower because they need to stand the force of gravity. they need a bigger resistance to fatigue, et cetera. We are using those muscle much more than we are, for example, using our triceps or our biceps. But what we have seen is that if you are having a faster typology in one muscle, you will have more fast fibers in almost all of your muscles compared to someone with a slow typology. For example, here, you can see that the soleus, which is a calf muscle, is a very slow muscle. It has a high percentage of slow fibers, while, for example, the vastus lateralis is somewhat more fast. In general, it’s a faster muscle when compared to the soleus. Nevertheless, if you would compare a person with a fast hypology, which you see here with the green line, If you would compare it to someone with a slower typology in most of the muscles that you compare it to, the fast ones will have more fast fibers or less slow fibers as it is depicted on this slide. Indicating that there is a sort of across muscle phenotype. And if you have insights in the muscle fiber type composition of one muscle, you can then further translate that information to the whole body. Now, our non-invasive technique, we obviously validated it in sports. And I saw in the introduction of this webinar that you did mention exercise physiology. So I decided to give you a little insight in what we, for example, see in elite athletes when we are looking at those muscles. But I won’t go into detail. If you want to know more, I’ll give you a resource to fully understand what’s the importance of this muscle fiber type compositions in sport. But just to show you an example, what we did is for example, we measured 70 elite athletes in athletics, somewhere long distance, somewhere middle distance, somewhere sprint athletes, and we asked them to join us for our scanning visits. we put them under the scanner. And as you can see from the marathon up to 1500 meter, we mostly see athletes with a slow to an intermediate typology. Well, if we look at distances, like for example, the 800 meter, you see that they have a more, a bigger heterogeneity into the people that are presented in those groups. Some people will have a slow typology and other will have a much faster typology. When we then look at the 100 meter or the 200 meter, we almost only see people with a fast or up to an intermediate typology. And that’s not abnormal because for example, those people need to generate a high power and high movement frequencies while the ones like marathon runners, those are better off with more efficient fatigue resistant slow fibers. So we can see different profiles when we look in athletes and we use this technique now to for example help you in finding the right talent in talented youngsters from for example 16 years onwards. We didn’t We can only do this in athletics. We also did this in, for example, cycling. And interesting to see is, for example, that road cyclists are rather slow, indicating that even a Van Aert, or well we didn’t measure him, but as an example, would have either a slow or an intermediate typology. And you might think, but he’s really fast, no? He can win a sprint, and that’s true. But he’s probably the fastest of all slow and endurance type of cyclists. and not unreasonable to see that they have a lot of slow fibers because they need to be on the bike for for example five hours before before they can do the sprint. On the other hand if you have a lot of fast fibers you can still be very valuable in sports like BMX or in track caring in which you need those very fast fibers to make fast accelerations. As I said, I won’t be able to go into detail. I did my PhD on this, so I could talk on this for the rest of the hour. I won’t do that. But if you would like to know more, I made a booklet, an add-on to my PhD, which explains everything in very easy language with a lot of visuals. So feel free to download it. It’s free. and you can share it with whomever you think it would be interesting. Now, after my PhD, I decided not to leave the muscle fiber type composition, but to broaden its application, because I saw that it had a lot of implications also for your health. And one of the things that triggered me was, for example, the different muscle fiber type composition in obese and diabetic subjects. But as I explained to you before, I think that muscle fiber type composition might be a risk factor for metabolic diseases, but actually we’re not sure about cause and consequence yet. There are already some research papers available that show links in between the muscle fiber type composition and metabolic cardio metabolic properties. So we have some preliminary evidence, but also in these, the cause and consequence relationship is not always that easy to see. Moreover, they are in small groups and they are not always looking into the physical activity that the group is doing, etc. But I want to show you some evidence on the link in between these muscle fibers and these metabolic properties. For example, here you see on the x-axis the area of slow-twitch fibers. So if you have a higher amount, you have more slow-twitch fibers. If you have a lower amount, you will have more fast-twitch fibers. And in the study of Blackwood, this was quite nicely correlated with the whole-body insulin sensitivity in young individuals, so not yet diseased individuals. We didn’t only see this for features that are interesting for diabetes, but I obviously focused in this presentation on what’s already known in the field of obesity. There is a lot of research yet, and I couldn’t cover everything, but I’ll give you a flavor. For example, here is a research on male participants you have, the lower your fat percentage. And we actually saw the same kind of relationship in between muscle fiber type composition and body fat in our own unpublished data from a study from my colleague, Freek. Not only the body fat percentage, but in other studies, also the fat to lean body mass ratio has been shown to be quite nicely linked to the percentage of your muscle fiber type composition. And as you can see, this relationship was only present in males, while this paper was only done in females. So it seems to be a trait that is seen in all genders or sexes. There are also already follow-up studies which followed, for example, the muscle fiber or measured the muscle fiber type composition in the beginning of the research and then follow up body mass. And as you can see, for example, also in those studies in 40 male individuals, the body fat, which is the lowest graph on the right, is very good or is correlated with the muscle fiber type composition. But this is not all, the change of BMI over the time, this was a follow-up of multiple years, over the time, the change in BMI was related to the muscle fiber type composition in which the ones with a slower typology a lower positive, has a lower change, a lower weight gain during those years. And for example, also the weight hip ratio seemed to be correlated to the muscle fiber type composition. The link has not only been shown with current fat infiltration, let’s say, or current body but has also been shown to, for example, overfeeding, in which people with a lot of slow fibers tend to gain less fat or fat mass after 100 days of overfeeding. So also the way they handle nutritional changes seem to be different in persons with a lot of fast or a lot of slow fibers. fibers. And also in, for example, persons with morbid obesity who did a gastric bypass, it has been shown that people with a lot of type 1 fibers or their slow fibers have a higher weight loss when compared to people with a lot of fast fibers. So in the Or the link between obesity has different angles. It’s based on the body composition, or there is a link with body composition. But there is also a link with how you handle nutritional changes, as well as how you handle weight loss when having different muscle fiber type compositions. And we didn’t only see links with diabetes with obesity markers, but also with cardiovascular markers, like for example, the systolic and the diastolic blood pressure, which were all in favor of those slow fibers, but also some longitudinal studies who followed up over multiple years, in which it was, for example, shown that people with a lot of type 2X fibers, which is, so actually I didn’t tell you yet, but you have, when looking at fast fibers, you have the type 2a and the type 2x fibers. Those are two different types of fast fibers. The type 2a fibers more closely resemble the slow fibers, while the type 2x fibers are really, really fast and glycolytic fibers. And if you have more of those fibers, you seem to have a bigger risk to do a cardiovascular event. So this information then, yeah, triggered me to investigate this research question, to look at the link in between these fast fibers and these metabolic diseases. Moreover, I also further focus on the link of lifestyle as you might have noticed that people with a different muscle typology might, for example, react differently on different kinds of foods or on different strategies of food intake. And we also think that movement, that sports or exercise, physical activity might be a very important moderator in this relationship. So what am I currently doing? We started a study in May in which we are cross-sectionally testing 250 young and currently healthy participants. We are both phenotyping their muscle as well as their health and we will follow them up the coming 20 years in order to get more insights into this research question. This research is called the muscle monitor. I’m not doing this alone. I have a very nice and good team having my back and doing the daily organization of the tests. I have a postdoc, Jeppe, a PhD student, who is also a doctor, Lara, and we have a lab technician who is also helping us. I’m backed up by very good and more senior scientists as well, like my former promoter, but now my colleague Wim de Rave, who is an exercise physiologist, but who is also very good in the more fundamental omics stuff, for example. But also, I’m also backed, or we are also working together closely with doctors in, for example, endocrinology, Bruno Lapao, in cardiology, Ernst Rietschel, who help us to form these research questions as well as the research design. So, what we are doing is, we are first doing a big cross-sectional part in these 250 male and female participants. A lot of research that has been done was only in men, So we are including both sexes in this research. And we are doing deep tissue phenotyping. And we are combining that with detailed participant characterization. More specifically, we’re, for example, doing– or we’re taking muscle biopsies. We’re not only looking for the muscle fiber type composition, but we will also do proteomics. We’re doing a fasted blood sample, as well as an oral glucose tolerance test in order to look at the insulin sensitivity. We’re also looking into the physical properties, the current physical properties of these subjects. We are measuring their maximal fat oxidation, their VO2 max, their resting metabolic rates. But we’re also looking into their maximal voluntary force, as well as their rate of force development. So we characterize them, We characterize their muscles, functionality, as well as their training status. Moreover, we’re also looking into free living conditions. We’re looking into three days of food diaries. We’re looking into 10 days of physical activity monitoring. We are doing continuous glucose monitoring. And we are also asking some questionnaires on stress, sleep, and broader health behavior. As for the tissue phenotyping, we’re mostly interested in the muscle, but we also took or are taking subcutaneous adipose tissue samples, which will obviously be interesting to investigate also in this healthy, currently healthy population. And we’re also doing a broader cardiac profile or a broader cardiac screening, which we investigate the arterial stiffness, the intermediate thickness, the blood pressure and for example the heart rate variability. Lastly, we also have a scan day because all the things that I said now are done on the first scan day, on our first test day, but we also have a separate scan day in which we scan the whole body of those subjects using MRI, looking into muscle volumes, but also fat distribution amongst the body, as well as fat infiltration, both in muscle as well as in liver. And we are also investigating bone strength, density and geometry using peripheral, yeah, PQCT, peripheral quantitative tomography. In order to give you an insight in, for example, the MRI images, we are working together with a company called Springbok, who then provide us the muscle volumes of all those muscles, but also provides us with the muscle fat infiltration, which is very interesting in order to see if, for example, weight-bearing muscles have different fat infiltration over the time in these subjects. As I already told you, we have two lab days. On the first lab visit, we are doing the deep phenotyping. Then we have 14 days of free living. And then we have the scan visits. And we are currently working on the cross-sectional design. But in future I hope to get funding also for the longitudinal follow-up as I think it will become even more interesting to follow these currently healthy individuals with different muscle fiber type compositions over the years. And we are planning to do every five year follow-up up to 20 years. Current timing of the muscle monitor, we started in May. We are currently in September somewhere in the data collection. We hope to get the data collection finished by June 2026. And currently we have already tested 60 participants with an almost equal amount of females and males. see this is also a distribution in either non-fit as well as fit individuals in both in both sexes. If you want to know more about the muscle monitor you can have some more information by following this link up here. If you know people in between 20 and 30 because this is the age category we are targeting, you’re obviously welcome to tell them to join our study and we’re really looking forward to these longitudinal results. Now, as I told you, we’re not only looking cross-sectionally into the link between the muscle fiber type composition and these factors and you might think, okay, Elin, what do you expect to find already in this young individuals. A lot of papers that I showed you before were done in young individuals, so there is already a big heterogeneity, for example, in their glucose handling as well as in the link in between the muscle fiber type composition and the fat percentage was, for example, also done in young individuals. So we expect to see already some correlations in between the muscle and those parameters, but obviously the longitudinal follow-up might give us even more insights. Moreover, I told you that we were not only looking at the current or at the lab-based physical activity, we’re also looking into the free living conditions, And this is because we think that physical activity as well as nutrition can be moderators in this link in between muscle and these metabolic diseases. And for physical activity, this link is very clear and this will also be our follow up. if we would identify people with a faster typology to be at a higher risk of metabolic diseases, we would then try to target them with personalized ways of physical activity in order to lower that risk again and to prevent those individuals from becoming sick in the future. Why would exercise, for example, in the case of diabetes, be that interesting? Well, next to the insulin mechanism of getting glucose into your storage rooms, there is also a second way to get rid of these high amounts of glucose in your blood vessels. For example, exercise is a very good way to burn that glucose to get your muscles moving. Moreover, if you are moving, you will lower your glycogen storage and there will be more space for insulin to do its job as well. So actually the combination of insulin and exercise will be very important, not only for the ones with a fast apology, but possibly especially for those. Because when people are inactive, the slow fibers seem to have a better glucose uptake. And there are more glucose is going to those slow fibers. Well, if we get people to be active, the fast fibers seem to be able to keep up. They seem to be able to increase the amount of glucose uptake, not only in their slow fibers, but also in their fast fibers in the same extent. So it seems that the fast fibers or the people with the faster typology can be helped by, for example, exercise as the fast ones react better in comparison to the ones with a slow typology. Now, obviously, I’m an exercise scientist. Exercise is not only important for metabolic diseases like diabetes or obesity, but also for multiple other diseases like dementia, mental health, but also cancer. If you would be interested in some easy explained insights into how the exercise is important for those diseases, I’ve indeed just written a book, it’s called “De Beweegreden”. I have been writing it together with Professor Wim de Rave. It’s a popular science book, meaning that it’s easy to read even after hours, with a lot of interesting stories on how exercise can change your risk for diseases, but also if you have a certain disease, what kind of exercise would be more appropriate to do for health purposes. Voilà, I’ll hereby thank Basso for having me and thank my team for obviously supporting me in getting all this research done. And I’m looking forward to your questions.

Speaker 5
46:42 – 47:18
OK, I hope everyone can hear me, but I think so. Aileen, thank you very much. It was very interesting. For me, the muscle phenotyping, it was a bit abstract than before, but it was well explained. So thank you very much. But just to be sure, and perhaps I didn’t notice it during the slides. So you mentioned that is it possible to change your phenotype by some exercise or is it really genetically determined? I missed, I think I missed a bit of that.

Speaker 6
47:19 – 50:15
Yeah, yeah, that’s a very good question. Most researchers. Agree on the fact that the biggest part of the muscle fiber type composition is genetically determined. If there are changes possible, most papers find changes in between the two fast fiber types. So, in between the fast 2A ones and the fast 2X ones. So, the really fast glycolytic ones, you can make them a little bit more oxidative. So, in between those fast fibers, there seems to be a shift possible. However, a shift from fast to slow fibers has not been shown that often in healthy individuals. That doesn’t mean that diseases, for example, injury of the back in which you cannot move anymore, Those people have a very high amount of phosphorus. So in those people, the motor units, they change and they get a lot of phosphorous. So, well, to give a short answer, the biggest part will be genetically determined, but as researchers, we should also be fair to say that the research that is mostly been done is done over, for example, six weeks of training, or maybe 12 weeks of training, or at max one year of training. But we do not know what a longer exposure to training does to your muscle fiber type composition, because for example, in children, it’s non-ethical to measure your muscle fiber type composition, and then to follow that up over the years, that would be very interesting to see if a Wat van Aert was born with a faster typology and changed it to a slower typology or that it just kept the same over the years. At the moment, we, or most of us agree that the biggest part is genetically determined, but with the research that I’m doing now, we will phenotype those 20 to 30 years old at this stage and we will follow them up over 20 years. So this would be the first longitudinal research that also looks at those changes. Well, irrespective or, well, we do not know then if this is irrespective of disease or if this is also due to diseases that there might be some changes. So this is actually what we still need to find out over a longer time course.

Speaker 4
50:16 – 50:35
Okay, and you’ve mentioned that it’s a bit unethical to do it in children. Are there maybe other research techniques on the horizon that can have a bit of an insight in this physiology? Or is it really the way to go how you’re doing it now? Because it seems a bit painful.

Speaker 6
50:36 – 52:46
Yeah, so the muscle biopsies that will probably not be done in children easily. The only way I think it could be possible if it’s done while doing another surgery, for example, taking some, a piece of muscle while doing another surgery. Nevertheless, we have the scanner method, for example, the proton magnetic resonance spectroscopy method, which can be done before puberty. And we can already give you an idea if your muscle fiber type composition before the puberty, we don’t necessarily push that into the sports world because it’s very important to have a broad sports participation when you’re young. So we like it better that they’re only scanned, for example, at the age of 15, 16, in order to get the last talent identification step. Also, the MRI is very expensive and it’s not easy to get an MRI. If you need an MRI, you need to wait or you need to go in the middle of the night. So that’s probably also not the best way to go. We have been exploring with other non-invasive techniques. For example, if you can jump higher or if you can sprint faster, or if you can, your reaction to electrical stimulation of your muscle, can that also give you some insights into your muscle fiber type composition. And at the moment, we think that measuring multiple things, multiple characteristics, which differentiate slow and fast fibers might give you insights in that. So that could also be a way, but we hope in future to, for example, be able to have a blood withdrawal in which we would then be able to see muscle fiber type composition. So we’re currently trying to push that a step further to get it into the clinic or into the practice.

Speaker 4
52:47 – 53:09
Great. We’ve been receiving quite some questions and another question that we see this first I am a listener that wants to thank you for this very interesting presentation and do you believe that you can maybe heal metabolic diseases with exercise? And if so, is there an advised amount of exercise that we should

Speaker 6
53:10 – 56:05
suggest to patients? Yeah, I do believe that exercise is a very important medicine that we are not using at the moment. It’s a very potent and very diverse Medicine, if you’re interested in that, the book is all about it. But of course, I can give you some insights. I will specifically give you some insights on obesity because we’re talking about this today. But for the general population, you would… The guidelines are that you need to do 150 minutes of exercise weekly. If you are doing that, that should be moderate to vigorous physical activity. you should add or it’s advisable to also add two sessions of strength training on top of that because we need, we really need those muscles to safeguard us from diseases in the future. If you are doing intense exercises, you can lower the number a little bit to 75 minutes. So 75 minutes of intense exercise weekly could do the trick. Nevertheless, for every disease, there are typically different exercise pills, let’s say, that treat the disease even better. For example, I will tell you an example of osteoporosis. In osteoporosis, you will need impact to change the way that the bones are working. So, swimming is not that ideal for osteoporosis, while doing jump exercises might be much more interesting for osteoporosis. On the other hand, swimming might be very interesting for people living with obesity, because there is less impact on the knees, less impact on the ankles while doing or while swimming, but you will still have a lot of calories that are burned. As for people with obesity, we need a lot of, well, most research is showing that the more calories you’re burning, the better, obviously. Although exercise is very good for their metabolic health, it’s probably not the best strategy to lower weight. For that we also need the diet to be in place. The combination of diet and exercise might be the key to try to counteract this obesity.

Speaker 5
56:08 – 56:23
And another question is the muscle phenotype also there in like organs like the heart? Does it also have slow and fast fibers and is there also a possibility that you could have a different phenotype there?

Speaker 6
56:25 – 56:36
Yeah, good question. The differences in between muscle fibers are less pronounced in other organs, mostly skeletal

Speaker 5
56:36 – 57:02
muscle. And another question I have, is there a possibility that there is a different capacity in glycogen storage for fast or slow fibers? And you have any comment on that? Yes, so the the storage of glycogen might be a little

Speaker 6
57:01 – 57:44
bit bigger in fast fibers. They are using, well, slow fibers are more metabolically flexible. They can use both fat as well as glucose, but the fast ones are more reliable on those, on glucose, on carbohydrates, and therefore they have also a little bigger storage of those glycogen stores. Moreover, when doing high intensity exercises, the glucose will go lower, the stores will be used more extensively in phosphorus. So this is the way why these phosphorus are probably also safeguarded by exercise.

Speaker 4
57:47 – 58:05
Very interesting. We also are receiving some messages of people who want to buy your book. So that’s a good thing. Other questions that we are receiving is because you’ve already mentioned on nutrition, do you have any advice related to supplement use like creatinines or even ketones?

Speaker 6
58:05 – 01:00:47
Is it relevant or not enough research maybe? – Yeah, very good question. It all depends on what’s the aim. For health purposes, it’s probably most relevant to follow, for example, a Mediterranean diet. And you all know the guidelines, the “gezondheiddriehoek”, not sure if, well, the Flemish part will know what’s that about. I’m not sure about the Walloonian, if there is a Walloonian triangle, let’s say, but those things like eating a lot of nuts, having good fats like salmon, et cetera, those are very important messages on general diets. When looking into supplementation, for example, for your muscle, it’s very important to have enough amino acids. So you will need to get those amino acids in either via your normal diet or via supplements. It’s definitely possible to do so via your normal diet. For example, currently Skir has become very popular in the store or Quark, because those have a lot of amino acids in there. So those are good sources of amino acids. But for example, whey supplementation, you might have heard of that really specific supplementation for leucine, is also very potent in having those amino acids in your body. And you need those because your muscles are made of those amino acids. If you don’t have amino acids present in your body and you need them, you will shrink in your muscles. So you really need those amino acids either to bulk, to have more muscles in future, and also to safeguard the current muscle. So from a supplementation perspective, I think that’s probably the best thing to do. So supplements are interesting, but only for the one or two percentages that you really want to gain while doing very specific top sport exercises, but less interesting for recreationally active athletes.

Speaker 4
01:00:49 – 01:01:04
And maybe to end the last question, do we know if GLP-1 receptor agonists that are commonly used for the treatment of obesity affect the physiology of the muscles? Is there already research on the horizon for that?

Speaker 6
01:01:05 – 01:03:17
>> Yeah. Also part of the book, but a very interesting question. We as muscle scientists, we don’t — well, we do think it’s a good thing that those medicines are there, but we indeed see problems at the muscle level. Because, for example, if you would lose 20 kilograms of body weight, 8 kilograms of that might be muscle and 12 might be fat. So fat or fat-free mass, if it’s all muscle, it’s unclear. But a big percentage of that is fat-free mass. Of course, your weight is less, so you don’t need all those muscles. But the problem becomes when you’re gaining weight again after the medicine. If you’re gaining weight again, for example, if you lost 20 kilo and you’re gaining weight again, let’s say 20 kilo, you’re just back at the same level, which we see a lot after taking in those medications. It will be hardly impossible to also have gained muscle over that period because most of the patients will not change their behavior. They will not go and train to get the loss of eight kilogram in muscles to counteract that. That will probably not happen. So the problem might be that you will gain a lot of fats and in that way become, yes, sarcopenic. So in a state where you are losing muscle over multiple stages of GLP-1 antagonists. So we are obviously not against it because it has a lot of very positive side effects, but for muscle, it’s warranted to train or to be physically active to try to counteract the loss of those muscles.

Speaker 4
01:03:21 – 01:03:45
– Yeah, and of course we’re treating it as a chronic disease that is this. So it’s chronic medication and definitely with the support that hopefully the members of Basel are given, we will definitely keep that in mind. So maybe to wrap up, because we’ve been one hour, I’ve been listening to this very interesting webinar. We hope to have all the people here today

Speaker 1
01:03:46 – 01:04:00
join the Basel, join ACN and also Eileen, we hope that we can stay in touch through the ACN network. And thank you for this very interesting presentation. – Thanks.