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COVID and the brain: researchers zero in on how damage occurs

Reporter: Danielle Smolyar

Research Assistant 3 – Text Analysis for 2.0 LPBI Group’s TNS #1 – 2020/2021 Academic Internship in Medical Text Analysis (MTA)

Recent evidence has indicated that coronavirus can cause brain fog and also lead to different neurological symptoms. 

Since the beginning of the pandemic, researchers have been trying to understand how the coronavirus SARS-CoV-2 affects the brain

Image Credit: Stanislav Krasilnikov/TASS/Getty

image source:https://www.nature.com/articles/d41586-021-01693-6?utm_source=Nature+Briefing

New evidence has shown how coronavirus has caused much damage to the brain. There is a new evidence that shows that COVID-19 assault on the brain I has the power to be multipronged. What this means is that it can attack on certain Brain cells such as reduce the amount of blood flow that the brain needs to the brain tissue.

Along with brain damage COVID-19 has also caused strokes and memory loss. A neurologist at yell University Serena Spudich says, “Can we intervene early to address these abnormalities so that people don’t have long-term problems?”

We’re on 80% of the people who have been hospitalized due to COVID-19 have showed brain symptoms which seem to be correlated to coronavirus.

At the start of the pandemic a group of researchers speculated that coronavirus they can damage the brain by infecting the neurons in the cells which are important in the process of transmitting information. After further studies they found out that coronavirus has a harder time getting past the brains defense system and the brain barrier and that it does not affect the neurons in anyway.

An expert in this study indicated that a way in which SARS-CoV-2 may be able to get to the brain is by going through the olfactory mucosa which is the lining of the nasal cavity. It is found that this virus can be found in the nasal cavity which is why we swab the nose one getting tested for COVID-19.

Spudich quotes, “there’s not a tonne of virus in the brain”.

Recent studies indicate that SARS-CoV-2 have ability to infect astrocytes which is a type of cell found in the brain. Astrocytes do quite a lot that supports normal brain function,” including providing nutrients to neurons to keep them working, says Arnold Kriegstein, a neurologist at the University of California, San Francisco.

Astrocytes are star-shaped cells in the central nervous system that perform many functions, including providing nutrients to neurons.

Image Credit: David Robertson, ICR/SPL

image source: https://www.nature.com/articles/d41586-021-01693-6?utm_source=Nature+Briefing

Kriegstein and his fellow colleagues have found that SARS-CoV-2 I mostly infects the astrocytes over any of the other brain cells present. In this research they expose brain organoids which is a miniature brain that are grown from stem cells into the virus.

As quoted in the article” a group including Daniel Martins-de-Souza, head of proteomics at the University of Campinas in Brazil, reported6 in a February preprint that it had analysed brain samples from 26 people who died with COVID-19. In the five whose brain cells showed evidence of SARS-CoV-2 infection, 66% of the affected cells were astrocytes.”

The infected astrocytes could indicate the reasoning behind some of the neurological symptoms that come with COVID-19. Specifically, depression, brain fog and fatigue. Kreigstein quotes, “Those kinds of symptoms may not be reflective of neuronal damage but could be reflective of dysfunctions of some sort. That could be consistent with astrocyte vulnerability.”

A study that was published on June 21 they compared eight different brands of deceased people who did have COVID-19 along with 14 brains as the control. The results of this research were that they found that there was no trace of coronavirus Brain infected but they found that the gene expression was affected in some of the astrocytes.

As a result of doing all this research and the findings the researchers want to know more about this topic and how many brain cells need to be infected for there to be neurological symptoms says Ricardo Costa.

Further evidence has also been done on how SARS-CoV-2 can affect the brain by reducing its blood flow which impairs the neurons’ function which ends up killing them.

Pericytes can be found on the small blood vessels which are called capillaries and are found all throughout the body and in the brain. In a February pre-print there was a report about how SARS-CoV-2 can infect the pericyte in the brain organoids. 

David Atwell, a neuroscientist at the University College London, along with his other colleagues had published a pre-print which has evidence to show that SARS-CoV-2 odes In fact pericytes behavior. I researchers saw that in the different part of the hamsters brain SARS-CoV-2 blocks the function of receptors on the pericytes which ultimately causes the capillaries found inside the tissues to constrict.

As stated in the article, It’s a “really cool” study, says Spudich. “It could be something that is determining some of the permanent injury we see — some of these small- vessel strokes.”

Attwell brought to the attention that the drugs that are used to treat high blood pressure may in fact be used in some cases of COVID-19. Currently there are two clinical trials that are being done to further investigate this idea.

There is further evidence showing that the neurological symptoms and damage could in fact be happening because of the bodies on immune system reacting or misfiring after having COVID-19.

Over the past 15 years it has become evident that people’s immune system’s make auto antibodies which attack their own tissues says Harald Prüss in the article who has a Neuroimmunologist at the German Center for neurogenerative Diseases in Berlin. This may cause neuromyelitis optica which is when you can experience loss of vision or weakness in limbs. Harald Prüss summarized that the autoantibodies can pass through the blood brain barrier and ultimately impact neurological disorders such as psychosis.

Prüss and his colleagues published a study last year that focused on them isolating antibodies against SARS-CoV-2 from people. They found that one was able to protect hamsters from lung damage and other infections. The purpose of this was to come up with and create new treatments. During this research they found that some of the antibodies from people. They found that one was able to protect hamsters from lung damage and other infections. The purpose of this was to come up with and create new treatments. During this research they found that some of the antibodies can bind to the brain tissue which can ultimately damage it. Prüss states, “We’re currently trying to prove that clinically and experimentally,” says Prüss.

Was published online in December including Prüss sorry the blood and cerebrospinal fluid of 11 people who were extremely sick with COVID-19. These 11 people had neurological symptoms as well. All these people were able to produce auto antibodies which combined to neurons. There is evidence that when the patients were given intravenous immunoglobin which is a type of antibody it was successful.

Astrocytes, pericytes and autoantibodies we’re not the only  pathways. However it is likely that people with COVID-19 experience article symptoms for many reasons. As stated, In the article, Prüss says a key question is what proportion of cases is caused by each of the pathways. “That will determine treatment,” he says.

SOURCE: https://www.nature.com/articles/d41586-021-01693-6?utm_source=Nature+Briefing

Original article: 

Marshall, M. (2021, July 7). COVID and the brain: researchers zero in on how damage occurs. Nature News. https://www.nature.com/articles/d41586-021-01693-6

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Reported by: Dr. V.S. Karra, Ph.D

Transcription is a cellular process by which genetic information from DNA is copied to messenger RNA for protein production. But anticancer drugs and environmental chemicals can sometimes interrupt this flow of genetic information by causing modifications in DNA.

Chemists at the University of California, Riverside have now developed a test in the lab to examine how such DNA modifications lead to aberrant transcription and ultimately a disruption in protein synthesis.

The chemists report that the method, called “competitive transcription and adduct bypass” or CTAB, can help explain how DNA damage arising from anticancer drugs and environmental chemicals leads to cancer development.

“Aberrant transcription induced by DNA modifications has been proposed as one of the principal inducers of cancer and many other human diseases,” said Yinsheng Wang, a professor of chemistry, whose lab led the research. “CTAB can help us quantitatively determine how a DNA modification diminishes the rate and fidelity of transcription in cells. These are useful to know because they affect how accurately protein is synthesized. In other words, CTAB allows us to assess how DNA damage ultimately impedes protein synthesis, how it induces mutant proteins.”

Study results appeared online in Nature Chemical Biology on Aug. 19.

Wang explained that the CTAB method can be used also to examine various proteins involved in the repair of DNA. One of his research group’s goals is to understand how DNA damage is repaired—knowledge that could result in the development of new and more effective drugs for cancer treatment.

“This, however, will take more years of research,” Wang cautioned.

His lab has a long-standing interest in understanding the biological and human health consequences of DNA damage. The current research was supported by the National Cancer Institute, the National Institute of Environmental Health Sciences and the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health.

Wang was joined in the research by UC Riverside’s Changjun You (a postdoctoral scholar and the research paper’s first author), Xiaoxia Dai, Bifeng Yuan, Jin Wang and Jianshuang Wang; Philip J. Brooks of the National Institute on Alcohol Abuse and Alcoholism, Md.; and Laura J. Niedernhofer of the University of Pittsburgh School of Medicine, Penn.

Next, the researchers plan to use CTAB to investigate how other types of DNA modifications compromise transcription and how they are repaired in human cells.

A quantitative assay for assessing the effects of DNA lesions on transcription

Source:

http://www.rdmag.com

University of California, Riverside

 

 

 

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