 W�b am y tîm gweithio yng Nghymru. Mae'r Llywodraeth Paget Stifon yn ymgeithio'r Llywodraethau yn ystod gyda'r Llywodraeth Paget Stifon, yn gallu ffas cheeksu yng nghymru deolawr yn adillaidd i gymumhiliadau llunio mewn wneud. Byddwn i'r hwnnw i'r ddaeth o'r diwrnod hynny o gyfan y societyu cyfrifol yw gan i wneud bod unrhyw gweithiau. Rwy'n edyn ni'n haprïbodd yna y tu cyfrifol yng nghymru adding Professor Cherry Wainwright to our long and eminent list of lecturers. Cherry is the director of the Centre of Cardiol Metabolic Health Research and Co-Director of the Centre for Natural Products in Health at Robert Gordon University. She's also a member of her university's AWIRB. Cherry is currently vice president meetings for the British Pharmacological Society and within the BPS she has served on the integrated pharmacology and animal welfare panel for several years. Her research focuses on cardiovascular disease where she looks at the mechanisms underlying the pathophysiology of the disease, pathophysiology of the disease, to identify novel therapeutic targets for treating cardiovascular diseases. Cherry has worked with numerous animal models throughout her career from rats and rabbits to larger animals such as pigs and dogs. When she moved to Robert Gordon University in 2003, the university didn't actually have an animal facility, so she focused on cell work. However, because the cardiovascular system is fully integrated and changes can affect the whole body, she faced limitations. So the university applied for an establishment licence and Cherry got to resume in vivo work predominantly using mice. Today I'm delighted to introduce Professor Cherry Wainwright and her lecture getting to the heart of the matter how animal research has helped us understand and treat cardiovascular disease. I have to start off by saying it's an incredible honour to be invited to give this lecture today and particularly when you look at the very long list of people who've been before me, this includes a number of Nobel Prize winners. So I'm actually quite astonished to be standing here myself. For those of you who don't know where Robert Gordon University is, which is not uncommon, it's based up in Aberdeen, and its campus stretches approximately 0.9 of a mile along the banks of the River Dee, so it's a very pleasant place to work. So the focus of my talk today is around cardiovascular disease and around 7.6 million people in the United Kingdom today are suffering from some form of circulatory disorder. Approximately three people die every minute from cardiovascular disease. Of those around a quarter are under the age of 75. When you look at more globally, there are actually 550 million people across the world with some form of circulatory problem and 200 million of those have coronary heart disease. So despite the fact that there has been a lot of research in the area, there are still facing a major health issue which has both economic and social consequences. What's disappointing is that the global figures have increased by about 93% since 1990, which is quite shocking. That's not because of the lack of effort in trying to find out and find cures for cardiovascular disease. I think what I'd like to try and explain to you is the complicated processes that are involved in cardiovascular disease make it very difficult to predict and to treat in some cases. We might regard CBD as a disease of modern society but in fact it's been around for a long time and a beautiful study showing CT scans of mummies from Egyptian tombs has stated that major arteries in the neck, in the groin and in the shoulder region show presence of atherosclerosis. A further study looking at mummies from four different ancient populations showed that this atherosclerosis is also present in the coronary arteries and if you look at the age of the mummies, the estimated age of death, the older they were, the more of them had atherosclerosis. What's interesting about that and I'll come back to this point shortly is that individuals who were mummified tended to come from the higher echelons of society and therefore would have been the ones who had the most extravagant diets such as those rich in meats. The first description of a death from coronary heart disease however is attributed to Leonardo da Vinci who witnessed the very sudden and apparently peaceful death of an elderly man aged 100 years old and because he had special privileges as an artist he was given permission, he was allowed to perform human dissections. So he dissected this poor unfortunate man and found that what he believed was the cause of death was that the blood and the artery that feeds the heart was very dry, shrunken and withered. He used that privilege of human dissection quite a lot after that. He dissected around 22 human corpses but also extended his studies into animals, dissecting sheep, horses, birds, in fact probably anything he could get his hands on. From this he created his understanding of the circulation by drawing very detailed anatomical diagrams. But it was a little while later that William Harvey, one of the forefathers of this great institution undertook the first real studies to try and understand how everything worked together and basically identified that the heart and the circulation is quite a detailed plumbing system. He believed that to learn was to study anatomy and from his work he managed to elucidate that in fact the heart is at the very centre of everything and it receives blood from the venous side of circulation and it pumps it through the lungs for oxygenation and then pumps it around the rest of the body. As he said, the heart of the animal is the foundation of their life and so if the heart stops, life stops. Things took a long time to move on much further and I'm going to be talking a little bit about some very key milestones in our understanding of cardiovascular disease and with a little scattering of bits of work that I have done that maybe have helped to contribute to our overall understanding. But perhaps one of the main pioneers in making that link between diet and atherosclerosis was Nicolai Anttikov and he performed some studies in rabbits where he fed them certain foodstuffs such as egg yolks and found that when he took plasma from these rabbits he had quite a high level of lipids and when he looked at the arteries from these rabbits he found that there were fatty deposits and he found the same thing when he fed the rabbits with a pure cholesterol and he then went on to study in much more detail about the circulation of the heart and he made some very clear statements and ones that still hold true today. The first of these is that gradual narrowing of the coronary arteries is better than a sudden thrombotic occlusion. I think that's a bit of a no-brainer really. He also did quite a lot of work to study the collateral circulation of the heart and the collateral circulation is a network of blood vessels that we have actually only three main arteries that supply the heart muscle with oxygen and if one of them narrows then the other arteries grow little blood vessels to come and try and supply that bit of muscle that's been starved of oxygen with blood and these are called collateral blood vessels and he identified that the collateral blood supply to the heart is of primary importance in maintaining its perfusion. He also found that narrowing of the coronary arteries is accompanied by changes in the vascular wall so the shape and the diameter of the blood vessel changes and this is termed today as vascular remodelling and he also suggested that if you return blood flow to the heart by removal of a thrombus in a blood vessel then you get restoration of blood flow. So this was back in the 1960s and what it led us to was this understanding that atherosclerosis results in a narrowed internal diameter or lumen of a blood vessel and in the best case scenario this results in pain of angina which is pain in the chest brought upon by physical effort because the blood vessel isn't able to supply sufficient blood to the heart to meet the demands of exercise or the alternative is the development of a thrombus if the plaque breaks with the catastrophic consequence of what is known as a heart attack or an acute myocardial infarction which has two key consequences. The first of these is life-threatening arrhythmia and the second is death of the tissue of the wall of the artery. So in order to be able to address this very serious event we need to understand what is happening and so I'm going to start off with the worst case scenario and talk about what we know about these events and then I will move on to what we now know also about the process of atherosclerosis because I think it's important that we understand the pathological mechanisms of coronary heart disease to be able to identify new treatments. Somebody mentioned earlier on that it's good to recognise the pluses and the minuses and I think the first part of my talk will perhaps be less encouraging than the second part of my talk. So a little lesson in cardiac electrophysiology. Basically the way in which the heart contracts is that there are electrical signals sent from the top and the upper right chamber of the heart which passes down through the wall between the two main chambers of the heart and then propagate up the exterior walls of the heart and the rate at which these electrical pulses pass through the muscle determines the order of contraction so in fact although the electrical activity starts up here it is the apex of the heart that starts to contract first to allow blood to pump through the blood vessels. Now a lot of the early work looking at both cardiac arrhythmia and myocardial injury was performed in dogs and the reason that this was done is because it's a large animal model the heart is easily accessible it's easy to visualise the coronary arteries and identify a specific point at which a ligature could be placed around the coronary artery to induce or to simulate a heart attack and induce a myocardial infarction. It also allowed the measurement of electrical signals in both the normal and the ischemic tissue and you really don't need to take too much notice of these but basically when a heart cell is activated by an electrical signal it produces what is called an action potential that is determined by the movement of a variety of positively charged ions such as sodium, calcium and potassium. However when you look at the action potential that's measured in a tissue that is ischemic you can see that there are marked changes and in particular the action potential is shorter. What this means is that as electricity is conducted down the walls of the heart if the conduction is slowed there is a good chance that it's going to reach a point that has recently been activated to reactivate it sooner than normal. So this is an ECG in a dog showing the baseline nice easy to record ECGs. At the point of coronary occlusion within one minute you start to see changes in the ECG which are due to these changes here and within five minutes you start to see five to ten minutes you start to see extra beats so rather than a regular beat the heart is now going boom boom boom boom and within 15 minutes the whole electrical activity can get completely out of control resulting in ventricular fibrillation. Now the management of these arrhythmias that occur within the first 15 to 30 minutes at the onset of a heart attack are quite difficult to manage and for a long time and probably still the only approach to it was the use of antiarrhythmic drugs like lignocane and barapamil or in the worst case scenario electrical defibrillation. So if the patient is lucky enough to survive this the next problem that is faced is that of the death of the myocardium and RIMO came up with a theory around the wave front phenomenon of myocardial cell death back in the 1970s and again this is data obtained from dogs and it shows that with time after about 40 minutes of lack of blood flow to the heart because of thrombosis approximately 30% of the ventricular wall has died. Extend that to three hours and it's over 60% of the area that's affected has died and by 96 hours it's just extended a little further and so he looked at what the possible causes and stages of this tissue death were and in the first 40 minutes the main things that happen is that the energy source in the heart which is the denicine triphosphate ATP is depleted and the cells become quite acidic. Platelets that are in the blood vessels in that part of the heart become activated and the heart throws out all sorts of stress signals to try and set off a repair mechanism. Within one to three hours so the first stage is reversible if you restore blood flow at that point normally go back to normal but if it extends to between one and three hours we start to see irreversible injury where the tissue becomes swollen becomes edematous there is a massive influx of calcium and the cells become overloaded with calcium and inflammation is initiated and then over the next 4 to 96 hour period the cells become necrotic and die. What that means in the long term is that somebody who has had a heart attack the size of the dead tissue in the heart cannot be repaired it doesn't repair itself and so there is a consequent reduction in the ability of the heart to function properly and in terms of morbidity their life expectancy is going to be reduced. So that is the point at which the knowledge was when I started my research career and it kind of came about as a bit of an accident really because first of all cardiovascular pharmacology was not my strong point as an undergraduate and I'd actually plumped to go down the route of neuropharmacology but then Professor Jim Parrott from the University of Strathclyde was the external examiner for my BSE and after he was actually very late he was held back coming from the Middle East and so our drivers were at 7 o'clock in the evening and so once they were all over we all went to the pub waiting for the secretary in the department to phone us in the pub because of course there was no email in those days and mobile phones to tell us that the results were up on the board and a call came out for me and I was asked to go back and to go back into the examination room and obviously I was full of trepidation and Jim just turned to me and said would you like to come and do a PhD with me and I thought ok let's give this a try so it was a bit accidental and Jim was very interested in what are called prostanoids and I'm sure you've all heard of aspirin non-steroidal anti-inflammatory drugs like ibuprofen and the way in which these drugs work is that they block the production of certain compounds called prostanoids by blocking an enzyme called cyclooxygenase and aspirin was being looked at as a possible way of treating or preventing heart attacks at the time and so Jim was particularly interested in the thromboxane and the thromboxane and prostacytin because thromboxane is produced by platelets it aggravates more platelets it causes constriction of blood vessels and therefore probably not a good thing to have in a heart that's undergoing ischemic stress whereas on the other hand prostacytin comes from the cells lining the blood vessel wall the endothelium and that is an anti-platelet agent and it causes vasodilatation and what Jim found working with Susan Coker was that using a dog model and we actually used Greyhounds was that they could measure in the coronary vein so that's the vein draining the part of the heart that had been made ischemic there was a massive increase in thromboxane within the first 10 minutes and this was completely blocked by aspirin they managed to show the same thing in relation to prostacytin but as their work moved on what they found was that it was the balance between these two that determined whether or not arrhythmias were serious so if more thromboxane were produced than prostacytin you saw much greater arrhythmiar activity if it was the other way around if there was more prostacytin than thromboxane then this seemed to be antiarrhythmic the problem therefore is perhaps the use of aspirin wasn't a good idea because by blocking both thromboxane and prostacytin you were taking that balance away and it might be better to shift it more in the direction of prostacytin so my PhD was focused really on looking at thromboxane's synthetase inhibitus so that is a drug that blocks only the production of thromboxane but also as to whether or not addition of a beta blocker because beta blockers were also being trialled at the time as a means of reducing arrhythmias and heart injury and so my PhD started and it started a lifelong interaction with industry because it was co-sponsored by what was then Seba Gaigi and this is the very first paper I produced and upon the top here we for this study used a rat model so moving away from dogs for a number of reasons it was very reproducible and obviously it was a lot cheaper and I won't deny that that's one of the key reasons for moving to that model but what this shows on the top here is the electric power and as soon as you migrate to coronary artery you get these massive changes in ECG and five minutes later lots of arrhythmias and ventricular ffibrillation and every single one of those arrhythmias was counted and those of you under the age of 40 will probably not know that at the time there were no computers no sophisticated software it meant printing off reams and reams and reams of charts and sitting and counting every single arrhythmia by eye and as you can see over a 30 minute period sometimes in the region of 1400 ventricular ectopic beats and what we found was a slight antiarrhythmic effect of metoprolol and thromboxing inhibition but nothing spectacular but there was with the beta blocker and the beta blocker in combination with the inhibitor the TXA2 inhibitor a big reduction in ventricular ffibrillation but disappointingly the thromboxing synthetase inhibitor did not do anything on its own and I was also fortunate enough to go and spend some time working in Lajlo Securesh's lab in Seged in Hungary and Ish van Leipran worked with me because they had a model using conscious rats where the ischemia was induced under anesthetic and then after the severe arrhythmia period was over the animals were allowed to recover and this meant that we could look at infarct size as well and the marked thing here is that first of all if you look at infarct size after 4 hours compared to 48 hours you see it's much bigger is in with that wave front phenomenon of cell death and interestingly at 4 hours metoprolol reduced infarct size but after 48 hours we weren't releasing an awful lot this was kind of a a pattern that happened and many people and many scientists were looking at lots of different ways to try and salvage the heart beta blockers including metoprolol calcium antagonists like varapamel and aspirin and while animal studies tended to show that they were of benefit clinical trials didn't hold this out at all and the main reason is that in the experimental models we were giving the drugs before the onset of the heart attack whereas in people you don't know that they're going to have a heart attack and unless you do mass dosing then you're really up against it so really the only way forward was probably to re-perfuse and so the coronary thrombolysis became the next challenge or target and thrombolysis is basically the breaking down of a blood clot and when a blood clot stabilises if you think about when you cut yourself and eventually a scab forms that's because the blood clot has created these ffibrin strands that make it nice and solid but after a while you don't need it anymore so there is a system whereby an example called plasmin will literally cut up these ffibrin strands to break up the blood clot and so thrombolysis therapy was developed which was based on the ability of the activation of plasmin using a plasminogen activator and this gave rise to several well known ones such as streptokinase, urokinase etc and this worked very well clinically so the first ones were done in around the late 70s and this shows very nicely that you've got here a blocked artery in a patient before thrombolysis and after thrombolysis you can see that blood flow is restored and in terms of clinical benefit of that it looked quite good and it looked quite good and this is just an example that studied nine clinical trials which had approximately 45,000 patients across the nine trials total of 6,000 deaths and they looked at the time to intervention and if they found that thrombolysis was performed within the first six hours mortality was reduced by 3% 7 to 12 hours, 2% over 13 hours down to 1% part of that could be due to the sting in the tail and that is the fact that reperfusion the restoration of blood flow itself actually can worsen the damage that has happened during the ischemic period and Bob Clona was one of the pioneers who looked into and I'll give a bit more detail in a minute but they showed very nicely that the microvascular reperfusion so the collateral blood vessels that are there to try and supply the heart with blood in the presence of an ischemia actually they close down they block and so this results in what is called no reflow and if after 2 minutes of reperfusion in a rabbit model 12% of the area at risk had no reflow after 2 hours this increased to 30% and after 8 hours up to 35% so this could explain why we're not seeing on reperfusion the improvement in mortality in patients that we would hope for and so Bob Clona along with Eugene Brunwald developed this theory around reperfusion being a bit of a double-edged sword so again I don't really need you to take too much into notice of all the steps in this but under an ischemic condition I mentioned already ATP depletion and acidosis when you restore blood flow you get reoxygenation and a massive return to ATP production but what that does is it creates the production of very large quantities of what are called reactive oxygen species so these are radicals free radicals that basically fly around the cells and batter holes in the membrane and one of the things that they do is that they cause mitochondrial damage so the mitochondria are the respiratory powerhouse of the cell and they cause the opening of a pool called the mitochondrial permeability transition pool and that leads to massive cellular damage at the same time the acidosis is lifted so pH becomes normal that results in calcium overload and again that contributes to damage and so studies in not just dogs but lots of other species put together that whole concept of reperfusion injury and in fact in terms of what the consequence of that is well it sets off reperfusion arrhythmia which in some cases can lead to sudden cardiac death it causes stunning of the heart tissue which means basically a portion of the heart that doesn't contract properly but that is a temporary problem that eventually recovers but it can also cause this lethal cell death and there is clear evidence that at least my cardio stunning and reperfusion arrhythmia occurs in humans not just in the animal models but there is also the probability that the lethal cellular injury and the lack of reflow also happens it is difficult to look because of course we don't we can't just take the heart out of a human when they have recently recovered from reperfusion therapy so how to tackle this well the next thing that came along was a phenomenon called mycardial preconditioning and this was first described by Murray and Bob Jennings and it's defined as the ability of the heart to withstand prolonged and severe periods of ischemia after priming with prior periods of ischemia and the simplest way of illustrating this and this was discovered again in dogs is you just focus on the top here which is the timeline of coronary occlusion so this is a control group that was subjected to a 40 minute period of coronary occlusion and then four days of the blood vessel being reperfused in the precondition group they preceded that long occlusion with four one minute coronary occlusions followed by one minute periods of reperfusion and amazingly what this did was it dramatically reduced the extent of damage to the heart and in fact one of my first PhD students demonstrated something very similar against arrhythmia in rat hearts showing that there was an optimum time of a three minute occlusion followed by either ten minutes of reperfusion or 30 minutes of reperfusion that's markedly suppressed arrhythmia but if you extended that reperfusion period sorry that gap between the priming ischemia and the main ischemia to 60 minutes you lost it completely so is that applicable in the clinic is it something that you can do well maybe maybe not you need to know what's happening to understand how giving an insult to the heart for a bigger insult you know what's going on how can that happen well going back to where I started looking at thrombocsine and prostacycline Jim and I were very interested in looking at whether other compounds or chemicals produced by the heart could actually be triggers of ischemic precondition one that we were particularly interested in was adenosine now adenosine is a byproduct of ATP and I've mentioned that a few times ATP is the source of energy in the heart and during ischemia it is depleted very very rapidly and the adenosine that is devised into can move in and out of the cell through something called a nucleoside transporter and when it gets outside the cell it can act on certain receptors and activation of those receptors causes a reduction in heart rate it causes inhibition of platelets and it causes vasodilatation so these are the kind of activity that we would imagine would be protective to the heart and I was lucky enough at this point in my career to be after a very long 7 hour interview with Paul Janssen was awarded a 5 year research lectureship by the Janssen Foundation and this allowed me to pursue this concept and it's this point that we changed from a dog model to a pig model not because of anti vivisection activity although myself and Jim were often targets for that but principally because of ASPA coming in in 1986 where dogs were listed as a protected species and therefore would have had to have been bred specifically for the purpose and we had historically used greyhounds and there was not going to be anywhere that was going to breed greyhounds specifically for the purpose also pigs were becoming much more used as a model for cardiovascular disease because their physiology is actually much more similar to a human in terms of the heart rate, blood pressure and coronary anatomy so we started working with pigs and working with this very similar model of coronary inclusion and we looked at the levels of adenosine in the blood draining the ischemic part of the heart and found that it was markedly increased so Janssen were very interested in the development of drugs to inhibit this transporter of adenosine so that if adenosine was being released from the heart if we prevented it from going back into the cell perhaps we could protect the heart by these mechanisms and in fact the nucleoside transporter inhibitor did just that it reduced the incidence of ventricular ffibrillation very nicely and then when we tried, when we mimicked the effects of adenosine by stimulating the adenosine receptor with a synthetic compound we similarly saw a marked ischemic effect our interest didn't just stop with adenosine in the 90s endothelin was a peptide of great interest and endothelin unlike adenosine is perhaps not considered to be a good thing because what it does is it acts on smooth muscle cells is produced in the endothelium lining the blood vessels but then diffuses to the smooth muscle cells underneath to cause very very powerful vasoconstriction but at the same time it can act on its own receptors back on the endothelium to produce nitric oxide and prostacycin both of which produce vasodilatation so endothelium is a bit of an enigma in that it appears to do two different things depending on the site of action and it was shown in the early 90s and this is actually in the clinic not in an animal model but in the first hour or two of acute myocardin infarction was a massive rise in endothelin in the blood of patients after the onset of a heart attack and so we wanted to have a look and see whether endothelin really that may also influence the outcome of myocardial ischemia and so the first experiments that we did we infused endothelium at a very very low dose not enough to cause much of a change in blood pressure and we found a big increase in the number of arrhythmias and in the incidence of ventricular ffibrillation but if we treated with a drug that blocked the ETA receptor we reversed this effect interestingly though when we gave either endothelin or a selective ETAB activating drug as a short bolus dose before the onset of ischemia we saw a massive reduction in the incidence of ventricular ffibrillation and we went to late later went on to show that what it was doing was that it was causing mast cells to degranulate and the fact that mast cells are inflammatory cells that are resident in the tissue but ischemia causes the activation of mast cells so if before you applied the ischemic insult to the heart tissue if you can degranulate those mast cells you can actually prevent it with me and we showed that by demonstrating that we could reverse these effects of endothelin by giving a mast cell stabiliser which is in fact sodium promaglicate which was originally developed as a drug for the treatment of asthma so endothelin seems to do more it seems to do some good things and over the years gym, working with Agnus Fhaig in Hungary and myself we looked at a whole range of natural substances that came out of the heart and found a number of them were protective such as adenosine he looked at bradikine and nitrocoxide and then we found that some my kind of feeling were both protective and damaging what was interesting is that whilst that was going on there was a lot of work going into trying to identify what the mechanism under preconditioning was and it became quite clear that in fact a lot of what we've been looking at were regarded as triggers of ischemic preconditioning it's a very very complicated pathway which I'm not going to go into but I think the important thing at the end here is if you think back to what I said about reperfusion injury one of the key events that causes cells to die is the opening of this mitochondrial permeability transition pool and it looks as though preconditioning actually stops that so can you mimic preconditioning it was tried in the clinic in many cases somebody's in getting their heart reperfused and can you give them something that mimics or can trigger this preconditioning pathway and so a denocene was tried nitrocoxide was tried none of those worked there are some rays of hope on the horizon however cytosporin A is actually an inhibitor of MPTP and is showing some promising effects but most of the drugs that are showing some promise are things that modulate glucose so they modulate the metabolism within the heart and they are anticoagulants or interestingly going back to my PhD one of the interesting things about ischemic preconditioning is that you don't actually have to make the heart ischemic for it to work so in fact you can induce ischemia in the kidney in the liver even in the lower limb and it will initiate this preconditioning response and in fact lower limb ischemia has been tried in the clinic to see if that will try and protect the heart not too much great success it has to be said so in terms of whether it's clinically possible to precondition then came out the concept of post-conditioning and post-conditioning is really can you induce the short periods of ischemia after you've restored blood flow and this this study showed quite nicely that so if you've got a control group where you've got a 60 minute ischemia and 3 hours of reperfusion preconditioning 5 minutes of ischemia 10 minutes of reperfusion before the long occlusion or post-conditioning where you have the 60 minute occlusion followed by the short ischemia reperfusion it still protects the heart so where are we well I did say at the start some of the news is not particularly good in some cases and whilst the concept of ischemic post-conditioning seemed quite optimistic there's really only one or so studies that have shown that when you do that in patients it actually works and so I'm not sure how far much further on we are than we were in terms of my cardio salvage and Gersh put this together quite nicely a number of years ago really highlighting that the window of opportunity is extremely narrow if you go in too soon well can you get to a patient that soon has 15 to 30 minutes with 12 hour waiting times in ambulances in hospital car parks probably not if you leave it till after 3 hours the damage is already done and so you have this very narrow window of opportunity and I'll come back to it again and what really I find I think maybe some of the work that I did in my PhD helped to reach this position but basically if metoprolol is given before in the clinic if it's given before the onset of reperfusion you get about 30% of the mycardium can be salvaged versus placebo so maybe the old and other good ones as they say so I want to change tack a little bit now for the mask little well considering the fact that 40 years in the business and I've not really seen a huge amount of progress in terms of being able to protect the heart it's maybe better to take a step back and address the cause rather than the consequence and I also I mentioned earlier about the theories behind the development of atherosclerosis and very early studies in rabbits showed that if you feed rabbits cholesterol the severity of the atherosclerotic plaque is directly related to the amount of low density like protein in the blood and in fact studies in human patients if you look at the levels of LDL that the levels were much much higher in patients who had a mycard infarction than those who hadn't and so that gives us a good correlation between what happens in experimental animals and what we see in the clinical situation and quite how this leads to atherosclerosis though was really untangled by Russell Ross he developed this his response to injury hypothesis and basically what he was saying is that it's a bit of a a circus movement in that the cells lining the blood vessel wall are injured in the first instance by the presence of high cholesterol levels in the blood but that then lets off a circuit of repeat injury or chronic injury so if the cholesterol remains high then over time there's a massive series of events that lead to the development of atherosclerotic plaque and this is going to look very busy but it just really highlights the complexity of what happens and so a key event is the oxidation of LDL which is the bad cholesterol in circulation and when that becomes oxidised it damages the cells lining the wall of the blood vessel that then sets off a massive inflammatory response and that inflammatory response encourages smooth muscle cells to start to move from where they belong in the medial section of the blood vessel and start to move under the endothemial cell there at the same time they proliferate and they start to produce collagen that helps keep them in place and then that leads on to the accumulation of lipids so you get eventually an artery that has these big layers of lipid pools so what's the best way of dealing with that reduce cholesterol and the first drugs that were used were things like bile acid sequestrons which prevent the absorption of cholesterol but the biggest milestone really was the development of the statins and they'd been around for quite a long time they were first identified in the 1970s but it took a while for them to be identified as inhibitors of this enzyme HMG CoA reductase and that is a crucial enzyme involved in the synthesis of cholesterol and the liver is the main organ that determines our cholesterol levels cholesterol is required we need it to feed our brains and undertake numerous functions but the liver only produces cholesterol when it's needed and if you've got an excess of cholesterol in the circulation the liver goes not making any more so if you can inhibit the production of cholesterol by the liver which is what the statins do then the liver goes oh I need more cholesterol now to produce bile acids and bile salts so it produces these receptors that then suck up the cholesterol from the circulation the statins started being looked at and studied for potentially treatment of the slowing of progression of atherosclerosis first of all largely in rabbits because this one the Watanabe heritable hypolipidemic rabbit was very prone to atherosclerosis and statin treatment reduced lesions by approximately 30% and narrowing by 50% and then the west of Scotland coronary prevention trial showed very clearly that if you give people statins then death from all cardiovascular causes is very markedly reduced so statins are now in regular use in patients who have high circulating cholesterol levels now just a little bit of variation on a statin a lot of I talked about oxidation of LDL and a lot of people focus on that but there are other ways in which LDL can be modified and become equally damaging and that is through chlorination and there is an enzyme called myeloperoxidase that produces hyperchlorite which is a highly reactive chlorine containing free radical and this can chlorinate LDL as well and we wanted to explore this and see whether that too can encourage the process of atherosclerosis so using a genetically modified mouse the ApoE knockout mouse which is prone to atherosclerosis when fed an atherogenic diet we fed these mice a diet we then removed the seracic aorta and the spleen and we isolated the inflammatory cells from the spleen which we then labelled with a radioactive label and we exposed or treated the blood vessels with chlorinated LDL and measured the adhesion to the blood vessel and what we found was that the chlorinated LDL produced a very big increase in the ability of inflammatory cells to stick to the lining of the blood vessel and when inflammatory cells bind to a blood vessel wall it's through certain types of adhesion molecule that are expressed in response to the high cholesterol and one of these adhesion molecules P-selectin we found was responsible for this because when we blocked the P-selectin the response to the chlorinated LDL was completely lost and I like putting in some pretty pictures this just goes to show this is the lining of the blood vessel wall those are the endothelial cells no P-selectin treat it with chlorinated LDL and you get lots of expression of P-selectin we then started doing some work with a company called Nycox who were producing a novel version of pravastatin which is one of the most commonly used statins today called nitrated pravastatin and basically they stuck an extra chemical group on the structure that meant that it released nitric oxide in addition to blocking the enzyme and so we took this into the model I've just described to you and in some of the mice we then gave them NO pravastatin or pravastatin for five days before we isolated the blood vessels and their monocytes and what we found was that while pravastatin didn't really itself prevent the adhesion of inflammatory cells if you had a nitric oxide donating part to the chemical structure then you could see a big reduction in adhesion and likewise it was able to prevent the adhesion induced by chlorinated LvL that compound has been through quite a lot of other trials it's not made it anywhere to the clinic as yet but I do think that it is a real opportunity for building sort of bifunctional molecules having two different mechanisms of action so moving on to the very last part of my talk in terms of atherosclerosis in addition to prevention then the treatment is also very important and Doctorin Grunzig developed the process of angioplasty which I'm sure many of you have heard about which involves progressing a wire down the coronary artery to the point of lesion and break it up and therefore revascularising or restoring blood flow but at the same time as with reperfusion injury there's a bit of a sting in the tail and that is previously angioplasty bits of artery can often re-narrow and this is termed restenosis and so the colleagues that I've worked with many years before and Seba Guygy had now become the artist came to me and said we'd like to do some work with you but we want you to work on blood vessels and would you be interested in restenosis and I said well let's give it a try so we started by developing a model in rabbits looking at the response to this balloon injury and did very much a time course study of the variety of changes in the blood vessel wall and about two days after the balloon angioplasty this was in a subplavian artery of the rabbit about two days afterwards you get what is called vessel shrinkage or recoil where the the blood vessel kind of reacts to the over stretch by shrinking down and then over seven days the blood vessel starts to change in shape and the walls become thicker and we get what is called a formation of a neo-intima normal artery and that is an artery that's been balloon injured and that's the tissue that's grown into it and when we stained for inflammatory cells we found that there was quite a lot of inflammation present in in these artery walls so to demonstrate that inflammation was important in the process of restenosis we took some rabbits and we made them leucopenic by using an antigen to a leucocyne common antigen which we gave prior to the angioplasty procedure so that the leucocyne count was almost zero and then we performed the angioplasty and we found that compared to control animals with a full complement of inflammatory cells when we made them leucopenic they were the size of the neo-intima was markedly reduced and that just shows you the difference between the the two groups however making patients leucopenic is probably not a very good idea so the other thing that we needed to target was the proliferation of smooth muscle cells which predominantly make up this neo-intima and so we were interested in trying to look at drugs that would do this and anti-cancer drugs are anti-proliferative they prevent the proliferation of smooth muscle cells and so we came across one compound that acts as an inhibitor of an enzyme called pharmasal transfer agent which was going through trials as an anti-cancer agent and we asked the question could we prevent smooth muscle cell proliferation with this drug and rather than giving the drug systemically we opted to use a special balloon with pores in it so that we could bathe the piece of artery that was being angioplastic with the drug rather than having to give it systemically and what we found is when we administered this pharmasal transfer agent inhibitor through a balloon catheter this is using a pig model in this occasion with a pig coronary artery we got a massive reduction in injury in response to FPT3 at the same time coronary stenting was becoming a particularly common way of trying to address particularly the shrinkage of the blood vessel after angioplasty but the problem with it is that you put the stent in you get a good response in the first instance but again as time goes on the tissue begins to grow around the metal stent however we managed to demonstrate with our FPT3 that even in the presence of a stent we could reduce the amount of neo internal formation or slant we managed to obtain human arteries from amputated limbs by working with vascular surgeons and we could show that if we took rings of the arteries from human patients put them into organ culture we get the same kind of growth of neo intima and that we could prevent that FPT3 and we got to the point of putting in a patent to protect this and then along came two drugs that were already in the market for other uses as anti cancer agents very quick to repurpose and these were pachytaxyl and xyrolymus or rapamythin and they made it very very quickly into the clinic sorry pachytaxyl works very much in the same way as our compound did xyrolymus has both anti-proliferative and anti-inflammatory actions and both are used to a great extent interestingly I came across this the other day in the 2022 to 32 projections our market value is expected to reach in excess of 50 billion dollars so big money and we missed out very last slide really just to say that I've taught a lot about understanding the pathology of disease as a way of identifying in how we can treat disease in some cases successfully in other cases not but sometimes we learn things the other way around and we were interested I developed, I do quite a lot of work in cannabinoids and we were interested in cannabidiol which I'm sure many of you have heard of CBD, people buy it on the internet and use it for reasons I don't think they really know but it is quite a powerful drug and we used CBD in our rap model of coronary occlusion and we found that it was really good at reducing infant size now CBD is actually quite a dirty drug it acts on various receptors and one receptor in particular it's quite powerful that is an orphan receptor called GPR55 and GPR55 is still a bit of an enigma and I was discussing this with a guy called Peter Grizzly from Asper Zenica as you do in the bar after a long day at a conference and we were talking about this data and he said oh we're interested in GPR55 we've got some mice that don't have the receptor would you like them and so that started off a whole program of research that is perhaps more reflective of what I've been doing more recently and we found that if you stimulate GPR55 with its natural ligand which has been now identified as LPI or mysophosphatetaminositol you can actually worsen cardiac injury that supports the story about CBD which is an antagonist of GPR55 has been protective but it goes further than that because we actually now know that this receptor is very important in a lot of things these mice with age develop cardiac dysfunction so as they get older their ability of the heart to contract is decreased and the ability to respond to stimulation by isoprenulant is reduced they're also obesity prone if you feed them a high fat diet they blow up like little balloons they're also very lazy they don't move around an awful lot and working with colleagues at Dundee Harry Hunder we found that they have quite abnormal insulin signaling in both the fat and the skeletal muscle and a recent study that the data is not published yet is that in fact in the metabolic tissues like fat and skeletal muscle if you activate your own chrony you get an improvement in insulin signaling on the contrary however we're finding that it impairs cardiac function and I think the really important story there is that everything is interlinked and what's good for one setting might not be good for another and so it's really a few take home messages now the cardiovascular system is integrated it's fully integrated the heart, the blood vessels the components of the blood that circulate within that system all talk to each other the regulation of the cardiovascular system is achieved by the brain and chemicals circulate around in the blood and it can communicate with other organs and vice versa coronary heart disease is really complex and it's a multi-organ condition and conditions that primarily affect other organs can also, such as diabetes can affect the health of the heart I've concentrated on animal work that I've done we also do a huge amount of cell based work that leads up to working within the animals but although isolated cells can tell us a lot to understand a complex system like this it is absolutely essential to be able to study it in the whole animal before I go, I think I just need to say a big thank you particularly to the army of PhDs and postdocs that have worked with me over the years but with countless academic collaborators too many to name so I've just put up some of the institutions I've worked with a lot of industrial collaborators and received very generous funding from a number of charitable organisations as well as the research councils and I'd be delighted to answer any questions if you've got the energy left and aren't too desperate to get to the drinks thank you so much for a fascinating talk we do have a couple of minutes I'm sure for questions there are early questions I thought there would be Mike we've got a microphone on me yes I'm sorry I think I've talked a bit longer thanks very much really interesting talk really enjoyed it you seem to use rabbit models quite a lot I was just wondering why that is not so much now as back in the probably 80s and 90s rabbits are actually a really good model of atherosclerosis they're a bit like someone you feed them cholesterol and develop atherosclerotic lesions there are other there are genetically not genetically modified but genetic strains of rabbits like the Watanabi one I mentioned and we also worked with a Foxfield rabbit and they show demonstrated atherosclerosis quite why rabbits are so pro I don't know but now we have models small rodent models rats are resistant to atherosclerosis pretty much you can feed them cholesterol but they won't develop atherosclerotic lesions but if you use something like the ApoE knockout mouse or the LDL knockout mouse feed them cholesterol you've got atherosclerotic lesions everywhere so it's just again variation in species and that's what we need to be careful about is how you can extrapolate that to humans let me know if you can't hear me that goes a really fascinating lecture thank you I was reading recently in the media that HDL might not be the good cholesterol that we thought of those is there any good news is there a hope that there is good cholesterol I mean it's it's more about the ratio between HDL and LDL that's been of interest so you can have high LDL but if you have high HDL as well then it's the ratio that's more important so yes I think there is a bit of bad press around HDL but I think for now trying to get the balance in the favour of HDL is better than leaving it as is that was absolutely fascinating given that you've very clearly stated that you need to look at these things on a whole system basis how are you approaching the 3Rs in relation to the phoncology and the medical disabilities okay that's a really good question and I didn't really have chance to address that but we take a very measured approach back in the day there was no cell based studies that we could really use and so everything went straight into in vivo but now we have so many tools to hand in terms of cell based studies the last slide I showed well one of the last ones that I showed with human blood vessels that we we kept in organ culture we actually have done that with pig coronary arteries and mouse arteries and so on so as a form of intervention drug intervention then we do all the build up to the work so that we know what concentrations we're looking for and so on and so forth to help reduce and good statistical and experimental design and one thing that we're doing at the moment is the influence of biological sex on the outcome and on pathophysiology is highly important and so historically while we tended to use male at the species we now are using both males and females and then finally the one thing that we have we have done is looking at non mammalian models so one of the things that we're interested in it's maybe not quite so easy to look at cardiovascular physiology when the sea elegans were for example we've started using as a model of obesity and so if we're looking we'll be looking at compounds that interfere with the development of fat their position and so we've got some really nice data just about to come out looking at sea elegans so yes I fully appreciate and I fully support the three Rs and do what we can at the end of the day there are certain things that we cannot look at without the whole level okay thank you very much thank you very much I was just wondering you started off by saying that there is a great deal of patients out there with cardiovascular disease numbers of distortion that are really amazing what is the position of clinical trials if you look at your cell systems and your animal models how do you see that in using clinical trials patients and how that relates to coming up with solutions to this disease okay I mean clinical trials are carried out generally when you have an intervention that you have shown that in all likelihood there is a chance of getting a good clinical outcome but the cost of clinical trials is absolutely enormous and the number of compounds and interventions that fail before they reach a clinical stage it could be that in the laboratory animal it is looking absolutely superb and then it goes through regulatory toxicity testing and you discover that the drug maybe hits the Herc channel for example which is one of the very important screens for drug safety because that can lead to cardiomyopathy so you might have the perfect compound and it fails because it blocks that channel so the process of developing a medication is a long arduous one and more potential compounds or interventions will fail before they even get to the clinic and once they do get to the clinic then you're relying really on being you know you're trying to translate what's being found in an animal model usually relatively healthy to sick people probably with multiple comorbidities so it's all we can do all the animal work I think can do is inform us about what's going wrong identifying what we should be targeting but it's not going to guarantee a positive clinical outcome I don't know if I've answered your question properly though Thank you as a non-scientist I find that quite accessible really grateful If you were visiting a relative in a heart unit and it happened to by luck one that's well funded and well staffed at these challenging times and you developed symptoms of a heart attack what would you ask the staff to do? If I develop them all the me if I was conscious and able to speak I would probably ask them to get me into a cath lab as quickly as possible so that they could have a look and see well first things first they do various blood tests to look at things like CK levels and so on but you know I think if I was fairly sure I was having a heart attack I would want to get straight into that cath lab and be perfused as soon as possible because time is of the essence and very recently there are actually plant sterols on great news either and that statins don't have any effect on plant sterols and then switching from latter to marjorim might not be the right thing to do and is that just in controversial or does that theory have legs? Not being completely familiar with the topic I can't say either way but I think it may well have some legs you know there's the very first study I talked about was egg yolk you know egg yolks were used to feed rabbits and so for many many years we were told to steer clear of eating too many eggs because the fact that they could raise your cholesterol levels and now we're told to eat eggs because they're really good for us so I think there are things that come and go and the plant sterols I mean it's because you've got your mono unsaturated polyunsaturated and saturated fats and in some of these butter substitutes it's not enough of the polyunsaturated fatty acids so there's probably mono unsaturates that probably are good for you so I think we're sold a lot of hype sometimes by the food industry and I think some of the drinks that are suggested to lower cholesterol when I'm down to about I won't name any for few you mentioned drink just then are there any other questions I can be found by the wine I'd just like to thank you all for coming I'd like to thank all the entrance including the shortlisted entrance I know it was hard for the judges to come to the decisions they did so please have a look at all the shortlisted entrance that are described in the programme that's the word congratulations again to the winners and thank you very much again for a fantastic lecture thank you