 Okay, perfect. So thanks of all first of all for the kind introduction Yeah, that's right. I want to talk to you today about the gut microbiota and the brain And I just want to tell you now my talk is not for the faint hearted Okay, I need you all your attention so you can understand the concepts that I'm gonna explain to you today So let's take you back first by one century where Russian immunologist Eli Meshnikov lived now he was He won the Nobel Prize and he was famous for immunology, but actually not many people know is that he got interested in bacteria in the later in his life and When he went to Bulgaria, he said hmm why are all these people living so long and eventually what he put it down to was the Yogurt that they were eating now. It wasn't just the yogurt that they were eating. It was the bacteria in the yogurt So he gained this idea that bacteria were beneficial for us and he actually wrote a book about it Now being a good scientist He actually put his medicine to test and he took a soured milk every day and believe it or not He lived to the ripe old age of 71 Not bad. It wasn't until 1990 where we revisited the concept of bacteria and being helpful for us Oops So they got microbiota now. What is it and what does it do? So they got microbiota? It's a two kilogram amount of bacteria which sits within our guts It's a highly diverse community and each thing each bacteria in our guts makes us unique It gives us a fingerprint because each got microbiota is unique Now what does it do? It has metabolic functions structural functions and immunity functions However, if we were to take a tiny little spaceship Enter our miles and go all the way down to our bombs It would be about seven meters in length and we'd encounter 100 trillion bacteria Yeah, that's quite a number of bacteria right and when we count all the number of cells in our bodies and all the number of cells In how many cells are in our bacteria? We would find there are actually more bacteria than human It's crazy, huh? Okay, so back to the metabolic function. What does it do? It help the bacteria help us digest foods, which we cannot in addition to this they have a Structural function so it helps keep our gut barrier nice and tight in addition to this the immunity so 80% of our immune cells lie within our guts and so It makes the microbiota the bacteria in our guts and a key educator to our immune system So but as your mother probably told you it's all about balance is all about moderation and just like that That's how it is in the gut microbiota We need some good bacteria and also some bad bacteria which educate our immune system and tell us what we need to attack So what the good bacteria do they do crowd control of all the bad bacteria? Yeah, and this is giving a happy healthy environment for us and makes us happy and healthy too However, when they're unlikely situation or likely situation when the bad bacteria overpopulate all the good bacteria This is when problems arise This is when we have diseases and we have diseases in the gut such as irritable bowel syndrome inflammatory bowel disease and also diseases away from our gut such as asthma and Mood changes Yeah mood changes where the moods originate in our brains So now scientists are starting to look at the connection between the gut microbiota and the brain However, as I do my PhD at the Institute of Stroke and Dementia Research I want to talk to you today about the gut microbiota influencing the brain So in order for you to do this I need you to first close your eyes That's close your eyes not fall asleep. All right. Um, so just picture this scenario. Okay? It's the end of the day. It's about 6 p.m. And you're just following up some emails All of a sudden you have a weakness or you could have a weakness in the side of your face arm or legs And you're thinking whoa, this is a weird feeling and you want to tell your colleagues So you try and get up you try and tell them with your voice and you try and make eye contact with them however You start to you have fumbling with your words and your vision is somehow blurred and you feel very unbalanced So guys open your eyes again These are the symptoms what you experience when you're having a stroke and if you ever experience this or see anyone experience this Please call an ambulance within five minutes Okay, so what's going on in our brains during this time? Here's a nice depiction of our brain And it's nicely vascularized with vessels for water vessels vessels are tubes which carry blood and In the blood contains oxygen and nutrients and what it does is it supplies blood to our brains and keeps our tissue working and functioning properly But what happens when we have sort of a blood clot or a blockage of our vessels? So what happens is the tissue cannot get its healthy oxygen and nutrients and therefore starts to die and that's essentially a stroke Now just a little bit about the numbers here So stroke is the second cause of death worldwide and in 2015 the World Health Organization said 50 million people died from stroke Yeah, you know, there's only one drug which we can give in the clinic. It's funny Huh, and there's another catch. We have to give it within 4.5 hours So this is why we think hmm Maybe the microbiota could be helpful to us and this is what we're looking at in Aguilis lab at the Institute of Stroke and Dementia research So in order to tell you a little bit about what's going on We're gonna have to enter the lab. I'm afraid And I need to get on my protection You know because it's gonna be some messy stuff with mice poop everywhere Okay, so the first question is how does the stroke affect the got microbiota? So here we have some mice So we have the healthy mouse with the normal purple got microbiota nice and healthy And we have a mouse who's had a stroke a different color So a different got microbiota and what we did is we counted all the different species was in the gut And we found actually that The mouse who'd had a stroke had a decrease in bacterial diversity. So I had a less diverse got microbiome But before they were exactly the same. So this was telling us that the stroke is changing the got microbiota So this is the first question answered Next the next experiment before I go and I have to explain to you this little guy here So this is a germ free mouse or a microbiota free mouse And what's cool about these guys is because they've never encountered a bacterial species in their lives So they're a little bit strange. They always and they feed in a sterile environment They drink water in a sterile environment They were born in a sterile environment and so they don't have a got microbiota like the nice healthy purple got microbiota the normal mouse has Now what we can do with the germ free mouse is we can give it back a got microbiota We can put back a got microbiota And we can do this from different diseases like mouse with obesity a mouse who has asthma And we can see how the got microbiota can change the rest of the body as well So this is of course what we did without stroke So here we are again back with the normal mouse with the normal purple got microbiota and the mouse who's had a stroke We took a little bit of the got microbiota. So we isolated it and then we gave it back to the germ free mouse So again here we have the germ free mouse with a normal got microbiota And we have a germ free mouse with a stroke got microbiota And then they had a stroke. So you guys yeah, you look pretty intelligent. This is where I'm going to ask you a question So as scientists what we like to do is we like to measure the amount of cell death in the brain And this is how a one indicator. We say how bad the stroke is So who thinks the mouse with the normal got microbiota had a bigger stroke? Please put your hands up now one guy brave and Who thinks the mouse with a stroke got microbiota had a larger stroke. Please put your hands up Yeah, see I knew it. You are a small audience and you're right because the mouse who had the normal got microbiota Had a smaller stroke and compared to the mouse who had a stroke donor showing us that in fact We can change the got microbiota and affect brain disease So now you're saying okay, this is cool Becky. Yes But what are the mechanisms that are going on here? And as I said before I wasn't lying This is really forefront research. We did these experiments last year So we only have maybe three potential mechanisms which we can explore which we can reason Why the gut affects the brain and I just want to go over them really quickly now So the first way the got microbiota can affect the brain is by physical so direct connection from the brain to the gut The next one biochemical so as we said before our bacteria somehow little factories producing many chemicals Which can enter our bloodstream and change our brains Another one the immune system so our immune system is changing due to our gut microbiota and This can then go into the brain, too So let's go in a bit detail. So the first mechanism nerves So as this special nerve the vagus nerve connects directly from the brain to the gut and if we just zoom in here We can see so the gut microbiota can produce chemicals or it can directly tickle the Vegas nerve here and send signals back up to the brain Now we know this is a way because we found well scientists have found one particular species Which can actually improve the symptoms of depression? However, when we cut this nerve These symptoms are not improved with this bacteria anymore showing is that the gut microbiota communicates with the brain via this nerve Okay, the next mechanism is Bacteria can produce chemicals so as we said they can digest foods Which we cannot and produce vitamins and short chain fatty acids, but they can also produce neuro transmitters Now neurotransmitters are the chemicals used which neurons communicate with each other So two neurotransmitters Serotonin our feel-good neurotransmitter 90% is made in the gut actually Dopamine our reward neurotransmitter 50% is made in the gut and the gut microbiota can make many different other neuro transmitters Which going to the bloodstream and affect the way our neurons communicate with each other Okay, another mechanism in which the gut microbiota can affect the stroke is the immune system And as we said in the immune 80% of our immune cells reside in our guts Now depending on what type of bacteria we have in our guts also changes the balance of immune cells We have in our guts as well So if we have an aggressive or if we have bad gut microbiota We can produce a more aggressive immune response aggressive immune cells But if we have more good bacteria, we can have more calming and chilled immune response So we had this in mind when we did our experiments and we looked at stroke so we go back here and We look at the mouse who's had a stroke and who's had a normal gut microbiota or a stroke donor got microbiota And we looked at the balance of the aggressive immune cells versus the calming immune cells inside the gut and Guess what we found we found more aggressive immune cells in the guts of these mice who's had a stroke donor in compared to the normal donor In addition, we looked in the brain and believe it or not again. We found more aggressive immune cells in the brains of the mouse And compared to the normal donor in the stroke Okay And this is one reason why we think the stroke is bigger in the stroke mice compared to the normal donor okay, so Usually we're picking foods now I can take this off Usually we're eating foods which we think oh what can we eat to make us look more skinny and sexy But maybe we should start thinking about what we can eat to make our gut microbiota help happy and healthy so What can we do to support a gut microbiome? So I'm just gonna talk to you briefly about biotics. So biotics simply means life. So pre-life pro-life and anti-life Prebiotics, what are they these are like fruits and vegetables and like dietary fibers and legumes Which you can eat which is also found in this famous Mediterranean diet, which everyone should eat And what they do is they they're like food for our good bacteria and they encourage a healthy good bacteria Compared to a bad bacteria gut microbiome Another way in which we can support a healthy gut microbiome is by drinking Kefir and yackle what's so good about them they contain live bacteria and instead of encouraged Encouraging the growth of good bacteria. We simply add more bacteria into our good microbiome and Another way we can change our gut microbiome is taking antibiotics now the good thing about antibiotics is it kills the bad bacteria But you're also wiping out all the good bacteria as well And maybe we're all a little bit guilty of taking antibiotics when it wasn't necessary So, yeah And with that I would already like to say thank you for your time. You've been a great audience Thank you to the beautiful and intelligent 15 by 14 for spending time with me And also if you'd like like what you've heard and you're very interested please follow our lab the lease lab on Twitter and we also have a very hard lab meeting every year and Thank you very much for your time finally So now So now we have some time for questions So I'm going to repeat the questions in order to everyone for everyone to hear it. So please Someone has a question So the question is how you induce stroke in the mice, okay, that's a very particular question We can do it many ways actually So the moment we use three different ones see it's typically doing surgery and you're taking the medial cerebral artery And you're colluding this artery Poor animal Any other questions The question is how you define aggressive and chill bacteria and So aggressive bacteria sort of encouraging an inflammatory response So more specifically th 17 cells or I'll 17 or interferon gamma or things along these lines And a calming immune response is somehow dampening and already an aggressive inflammatory state So it's sort of anti-inflammatory such as T regulatory cells for example Please Do you think your upbringing is also important whether you have a good microbiota or not because when you're a child you're probably Especially in western world if you compare the summer with Eastern world Eastern world is more they Outside it there's dirt everywhere And in my experience people from Eastern world seem to have a better Immune system compared to people from western world even though life expectancy is more So essentially the question is if your childhood experience when you're exposed to microbes affecting your immune system Well, actually, yeah, you're right So the gut microbiota can change from many things for example our environments our Diets our medication our environment many things can change the gut microbiota So yes, you will start to see changes in the immune responses and also as your child You're exposed to different types of diseases and you're going to develop an immunity when you're young to different thought sort of things And it maybe the hygiene hypothesis is old-fashioned, but it also could be true So yeah, I think it's good for kids to get out in the dirt and get exposed to all the different stuff that they possibly Can and even travel to different places now that we can and So yeah, you're right. Yeah, it's just a lot of fun So we have time for one last question So the question is if the meat diet affecting your gut microbiota Well, yes, it does change the gut microbiota and so far protein has not been shown to be Beneficial in terms of and I mean probiotics are the best type of Probiotics to grow the good bacteria somehow meat was not associated. I mean it supports a gut microbiota But it's not being associated with an improvement of symptoms for example This would be so I think we should say thank you to Becky