Covid and the brain: A neurological health crisis

inflammation in the brain can cause dysregulation of a number of different cell types and have lasting consequences to cognitive function understanding that when the pandemic struck and we saw how profoundly immunogenic how profoundly inflammatory even relatively mild cases of covid could be i really worried about a neurological health crisis and i think we're watching that unfold right now the rates of persistent cognitive symptoms in people who have recovered from kovid is frankly alarming we need to understand how to intervene and offer effective therapy or there are going to be just millions of people suffering with these persistent cognitive symptoms [Music] i'm not an epidemiologist i'm not a virologist i'm a neurologist but i am alarmed by the neurological possible consequences of this pandemic and alarmed by the neurological disease that's already evident in in many many many survivors of covet even from early in the pandemic it was very clear to neurologists that covid infection results in a remarkably high rate of persistent neurological symptoms including quite a high rate of persistent cognitive symptoms that includes things like difficulty paying attention difficulty with the speed of information processing difficulty with concentration and memory and that is something that you know we should all be paying a lot of attention to that is really really concerning it's debilitating people are just not returning to their previous level of function and that's a major problem with 265 million people worldwide infected with covid and some estimates of as many as one in four people at least prior to the time of vaccination experiencing these cognitive symptoms this is a neurological health crisis i'm a neuro-oncologist and one of my clinical specialties is to take care of people following cancer therapy who have persistent brain fog you know cognitive impairment as a result of their cancer and its therapy and this so-called chemo brain or chemo fog is very similar to what people are describing after covid and so this so-called covent fog shares almost the identical symptoms and what we're finding in the laboratory is it that the two um types of brain fog also share a lot of the very same cellular changes that we think are are underpinning this sort of fogginess we know that with severe covet infection that many things can go wrong that severe disease is associated with blood clots that can cause stroke with even direct infection of the brain and with the consequences of multi-organ disease and damage but even after mild covid people were reporting persistent cognitive trouble and i wondered whether the inflammatory response just to the to the respiratory infection might be enough to trigger neuro inflammation inflammation in the brain and and consequently dysregulate these cells that are so important to keep in balance for healthy cognitive function what we discovered in the laboratory in mice that have relatively mild respiratory covid and then in human samples kovid elicits such a profound inflammatory response in the brain and as a result of that brain cells that need to work together in order to communicate and function normally were dysregulated in severe cases of covid there can be direct infection of the brain but in many cases there's no evidence of virus in the brain what's happening to affect the brain instead is a consequence of the immune response to the virus and what we studied was how the immune response to infection that was limited to the respiratory system could cause inflammation in the brain through signaling molecules that go from the lung through the blood and to the brain we found pretty high levels of inflammatory molecules called cytokines and chemokines in the central nervous system just from mild respiratory infection and together with that we saw inflammation in a particular kind of brain immune cell which is called a microglia when microglia and astrocytes become reactive they then can cause dysregulation of another kind of glial cell that form the insulation around axons quite literally like the insulation on a wire when that happens the neurons the communicating cells in the brain can't communicate with each other in their normal way not not as quickly and and not as well and so that can cause dysregulation of the whole circuit and cause cognitive impairment this pathophysiology is particularly prominent in covid now a lot more kids are becoming infected with covid and so one of the next things we'd like to explore in the laboratory is to understand how early life exposure to even mild respiratory covit might influence both brain development brain plasticity and cognition as a parent as a as somebody who takes care of children um in the clinic you know after covet exposure i'm i'm very attentive to how school is going to whether they're complaining about you know not being able to remember things if they're having difficulty finding their words to describe you know certain certain things in conversations their overall level of fatigue and i think there's there's many things to pay attention to as as a parent as a as a teacher as a as a physician it's not clear what neurological diseases people may be at increased risk for down the road and so it's of some real urgency to understand that to understand these neurobiological underpinnings um of this initial response to covet to know what people may be more susceptible to and and to reset these cells to a more normal state the risk of long-term neurological disease really gives me pause and and makes me not at all ready to decrease mitigation efforts i still feel that we need to be vigilant we need to not fatigue of these measures as difficult as they are we need to really maximize vaccination [Music] and and hope to to minimize the long-term damage that this pandemic is going to do for generations i think the lessons from chemo brain are really encouraging because the biology that we uncovered in the context of cognitive impairment are all potentially reversible and and that's really hopeful in more severe cases of covid particularly when there are clots and strokes and direct brain infection irreversible damage can happen but in these more mild acute you know covet cases this is all potentially recoverable it's of real urgency to understand the neurobiology to understand the basic underpinning of what is going wrong so that we can develop therapies to to intervene and and restore you know normal balance in the brain otherwise i think that there will be you know really profound long-term consequences of this pandemic on neurological health [Music]

Channel: Knowable Magazine

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Length: 8min 56sec (536 seconds)

Published: Thu May 26 2022