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Impact of COVID-19

Watch Professor Jon Gibbins explain the impact of COVID-19 on our heart and share an update on the research being carried out by University of Reading
Good afternoon. So as the summer of 2020 draws to an end, it’s perhaps interesting to reflect on what’s happened this year. It’s certainly been quite a strange year. Now most people’s lives have been turned upside down by the COVID crisis that swept across the world with varying degrees of disease in different countries.
And while this has been going on and whilst we’ve been relocating ourselves– I’m here in my office at home as I’ve been from probably around six months now working from here– many of us have been involved in research and studies to try and understand what’s going on in the COVID disease and why it is that some patients suffer so badly and are so badly affected increasing the risk of them dying. And it’s become clear– it was clear quite early on– that a major component of this relates to cardiovascular biology.
It was noticed very early on from patients in China and then this has been replicated across the world that patients develop the very severe form of COVID infection, if they die, post-mortem samples have shown to reveal large amounts of clots present in their lungs. And these clots probably were largely responsible for cause of death in many patients, although it isn’t entirely clear exactly why this happens at this point. But many of us, scientists and doctors alike, have been focusing on trying to understand what’s going on. What seems to happen is that clots form in the lungs.
And the lungs is the tissue that’s most delicate and I guess susceptible to this particular condition mainly because of the way that the lungs work and the way that the blood vessels are so delicate and the airways are so delicate inside the lungs. And what’s clear is that infection seems to cause a very dramatic inflammatory response so inflammation in the tissues in the lung. But it’s not actually just localised to the lungs. We also see clots forming in the heart– in the vessels in the heart. We see increased levels of strokes. And we also see clots forming in the kidneys. So basically, anywhere where you have fine circulation, it seems to occur.
And this causes a dramatic effect on the function of those organs. And, in many cases as I mentioned, this is not survivable. Now it seems that part of the problem is the cells that line the blood vessels– these are known as endothelial cells– and these form the barrier from the inside of the blood system to the blood vessel wall. And this is the location where an enzyme is found. It’s called ACE2. And ACE2 is found on the surface of endothelial cells. And it’s this protein that the virus is hijacked to find its way into cells and infect them. So endothelial cells become infected by the virus. And, therefore, they become the location of an inflammatory response.
And how this then goes on to cause blood clotting isn’t entirely clear. It is actually possible that the machinery that normally triggers your blood to clot, particularly platelets and maybe the coagulation pathways as well, might actually be involved in precipitating this inflammatory response themselves. But certainly one of the things that the coagulation or the blood clotting system is there to do is to detect when there’s damage to your tissues and blood vessels. And that’s effectively what happens during serious inflammatory conditions within the COVID patients.
And so it may be this sort of widespread damage to the lining cells of your blood vessels that potentially triggers thrombosis to occur, which then goes on to cause such problems in the lungs and other tissues. And it seems to be a cascade of events. And doctors have been looking at lots of ways to potentially prevent this or to stop it happening or to tame it down when it starts to occur. You could consider this to be like a perfect storm in many respects– all sorts of unfortunate things happening together which precipitate this really bad outcome for patients. And actually underlying this is what is often referred to as a cytokine storm.
So this is where the chemical signals in your immune system that control the ability of your immune cells to fight infections just go haywire, and you have an overreaction. And, in fact, there is some evidence that some of the immune cells, particularly cells called macrophages which is there to clear unwanted things that they encounter in your circulation– bacteria and infected cells. These become hyperactive and can in themselves damage the blood vessel wall. There have been other suggestions as well that the immune response that patients experience when they have a viral infection, and this could be any virus, but in this case, the COVID virus or the SARS virus, this response results in antibodies that are, for some reason, are pathological.
And there are groups in Europe who are looking specifically at that process. And we’re working with them to try and understand whether this partially explains the blood clotting process that happens. But I guess a really important question from all of this is what can we do with this knowledge. How can this be used to improve the outcomes for patients? Well, trials are under way to look at the effects of treating patients with anticoagulant drugs and antiplatelet drugs, either individually or together, along with a range of other different interventions to see whether this actually increases survival, improves the outcomes of patients, and reduces the levels of clotting that’s found– the unwanted clotting that’s found in circulation.
Other approaches that are being tried include trying drugs that suppress the immune system, the immune response which goes haywire and ultimately causes many of the symptoms. And this is something that is underway in a number of centres around the world. And there are some quite encouraging outcomes from some of these studies. But I think one of the big problems is not understanding really properly what the trigger is. So we are quite often treating things further down the line. And really, what we want to know is what ultimately triggers this in the first place and how could we prevent that. In fact, some of the drugs that being used are quite sophisticated.
And they are often used as relatively recently developed cancer treatments. But several other targets are also found in immune cells and so, therefore, have been particularly interesting in terms of finding new ways to prevent new infections. So what we’ve been doing here at Reading, well, we’ve joined forces with doctors and scientists in Reading and in London to try and design studies that enable us to try and understand what’s happening to the blood clotting system in patients and the immune system, principally, the clotting system in patients that are infected with the COVID virus and to see what specifically happens to the platelets and the coagulation response as patients move from being relatively tolerant of the viral infection to those that become really quite badly affected to see if we can detect things that may be useful in predicting which patients may be at a greater risk of going downhill.
Now there are challenges with this work. It’s not easy to work with samples from infected patients. That’s always going to be a challenge. But actually one of the biggest challenges we’re facing at the moment is a lack of patients to work with. The initial phase of the infection, at least in the UK, has subsided substantially. And so the numbers of patients in our hospitals, particularly in our ICU units, has declined dramatically. And this is causing problems in identifying patients that may be able to take part in some of these studies. And there are many of them under way, many of them nationally organised joining together hospitals from across the country. So they all contribute to one big study.
And this is being replicated in many countries around the world. But numbers are starting to increase. Everyone’s worried about what’s going to happen with a potential second wave of infection, particularly as the summer comes to an end as we head towards winter and the flu season as well. All impact these changes, including schools reopening, society going back or at least returning to some form of new normality, and, indeed, our universities opening their doors as well. So we’re rather worried what may happen down the line. But we are poised with a number of tests that we’ve developed, specifically, for these studies. And hopefully, they will be ready to go under way should this be needed. So COVID-19 is a complex story.
There are many people around the world thinking about this and working hard to try and understand how this disease develops. But I think one of the things that’s really important to leave with you given the context of this MOOC is the fact that this really is a cardiovascular-driven outcomes, or at least the more sinister outcomes from this disease really relates to abnormal cardiovascular function. And so many of the things that we strive to understand, cardiovascular disease in the population normally and the drugs that we develop may be very useful in some patient populations in treating and preventing COVID virus and more severe consequences from this.
Clearly, the months and years ahead will be important dependent on whether we identify better therapies and whether the vaccines that are in development are successful. Obviously, watch this space. And maybe I’ll update in a few months time when we run the MOOC again to see where we’ve got to. Bye bye.

Watch Professor Jon Gibbins, Director of the Institute for Cardiovascular & Metabolic Research, explain how COVID-19 impacts our cardiovascular system.

Scientists are still trying to understand exactly why infection with COVID-19 leads to such a wide range of outcomes; in many cases the infection is asymptomatic or results in a mild respiratory illness, whereas in some cases it progresses to a severe illness that can be fatal.

The severe symptoms are thought to be the result of an uncontrolled inflammation causing damage to the lungs and other internal organs. This can also stimulate the liver to produce excessive clotting factors, making the blood extremely sticky and causing blood clots to form around the body. COVID-19 patients are therefore at a higher risk of developing complications including deep vein thrombosis, pulmonary embolisms, heart attacks, and strokes.

In the video, Jon explains the results of the research into COVID-19 so far and the approaches currently being explored to mitigate the impact of COVID-19 on those with cardiovascular problems. He highlights the University of Reading research in this area and some of the challenges which scientists have faced.

Video produced September 2020.

Further reading

Learn more about what coronavirus means for you, if you have a heart or circulatory condition, take a look at the BHF webpages.

Explore microbes that cause infections and the techniques used by microbiologists to identify them in Small and Mighty: Introduction to Microbiology. This course starts again on 5 October.

Find out how the University of Reading is working together with partners to support efforts to fight COVID-19, treat the disease, and mitigate the impacts of the coronavirus crisis on our website.

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