Tag: covid risk

Categories : COVID PaediatricsTags :

Specific Nasal Cells Protect against COVID in Children

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Legend of spirals: This image highlights the appearance of nasal cultures from older adults, revealing distinct spiral-like patterns that were absent in cultures grown from children. Credit: University College London

Important differences in how the nasal cells of young and elderly people respond to the SARS-CoV-2 virus, could explain why children typically experience milder COVID symptoms, finds a new study led by researchers at UCL and the Wellcome Sanger Institute.

The study, published in Nature Microbiology, focused on the early effects of SARS-CoV-2 infection on the cells first targeted by the viruses, the human nasal epithelial cells (NECs).

These cells were donated from healthy participants, including children (0–11 years), adults (30–50 years) and, for the first time, the elderly (over 70 years).

The cells were then cultured to regrow into the different types of nasal cells. Using single-cell RNA sequencing techniques that enable scientists to identify the unique genetic networks and functions of thousands of individual cells, the team identified 24 distinct epithelial cell types. Cultures from each age group were then either mock-infected or infected with SARS-CoV-2.

After three days, the NECs of children responded quickly to SARS-CoV-2 by increasing interferon (the first line of anti-viral defence), restricting viral replication. However, this early anti-viral effect became less pronounced with age.

The researchers also found that NECs from elderly individuals not only produced more infectious virus particles, but also experienced increased cell shedding and damage.

The strong antiviral response in the NECs of children could explain why younger people typically experience milder symptoms. In contrast, the increased damage and higher viral replication found in NECs from elderly individuals could be linked to the greater severity of disease observed in older adults.

Project lead, Dr Claire Smith (Associate Professor at UCL Great Ormond Street Institute of Child Health), said: “Our research reveals how the type of cells we have in our nose changes with age, and how this affects our ability to combat SARS-CoV-2 infection. This could be crucial in developing effective anti-viral treatments tailored to different age groups, especially for the elderly who are at higher risk of severe COVID-19.”

Co-Senior author, Dr Kerstin Meyer (Wellcome Sanger Institute), said: “By carrying out SARS-CoV-2 infections of epithelial cells in vitro and studying the responses with single cell sequencing, we get a much more detailed understanding of the viral infection kinetics and see big differences in the innate immune response between cell types.”

Children infected with SARS-CoV-2 rarely progress to respiratory failure, but the risk of mortality in infected people over the age of 85 remains high, despite vaccination and improving treatment options.

The research underscores the importance of considering age as a critical factor in both research and treatment of infectious diseases.

Co-senior author, Dr Marko Nikolic (UCL Division of Medicine), said: “It is fascinating that when we take away immune cells from nasal samples, and are only left with nasal epithelial cells grown in a dish, we are still able to identify age-specific differences in our body’s response to the SARS-CoV-2 between the young and elderly to explain why children are generally protected from severe COVID-19.”

Dr Smith added: “Understanding the cellular differences at the initiation of infection is just the beginning. We now hope to investigate the long-term implications of these cellular changes and test therapeutic interventions using our unique cell culture model. This ‘gold-standard’ system is only possible with the support of our funders and the willingness of participants to provide their samples.”

The team suggest that future research should consider how ageing impacts the body’s response to other viral infections.

Source: University College London

Categories : COVID GeneticsTags :

Key Gene may Protect Against Severe COVID Infections in Men Under 75

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Photo: CC0

A certain variant of a key anti-inflammatory gene protects men under age 75 from severe illness and death when hospitalised from COVID, a genetic analysis of their blood shows. According to the authors of a major study published in The Journal of Infectious Diseases, the protective gene in question, an interleukin-1 receptor antagonist (IL1RN) variant, appears to tamp down inflammation, which can get out of control in severe cases SARS-CoV-2 infection.

The study showed that 124 men between the ages of 19 and 74 who possessed the IL1RN variant, called rs419598, were less likely to become severely ill after hospitalisation for COVID, and 80% less likely to die from the disease.

IL1RN is expressed naturally in the body. Different types of interleukin genes are known to dial inflammation up or down in the context of arthritis, and researchers say the results of the current study suggest that a similar dynamic influences the interleukin-1-related inflammation seen in COVID patients.

The findings, from researchers at NYU Grossman School of Medicine, stand out because historically more men than women are known to die from COVID, and the IL1RN rs419598 variant appears to selectively protect only men up to age 74, but not beyond that as age-related chronic illnesses unfold.

The research team used sequencing technologies for the study to determine the presence of specific genes or variations in the letter code that makes up genes in blood samples from 2589 men and women hospitalised for COVID at NYU Langone’s Tisch Hospital in Manhattan from March 2020 to March 2021.

More than half of the men and women in the study were older than age 60 and obese, factors that are known to increase the risk of death from the viral infection. Overall, more men than women (240 men, at 60.5%; and 157 women, at 39.5%) died from their disease, with women 20% less likely to die than men.

“Our study results show that among hospitalised patients, while women are still overall less likely than men to die from COVID-19, those men age 74 and younger who possess the IL1RN gene variant rs419598 are much less likely to suffer the severe inflammation tied to SARS-CoV-2 infection and less likely to die from the disease,” said study colead investigator and molecular biologist Mukundan Attur, PhD. Attur is an associate professor in the Department of Medicine at NYU Langone Health.

Among the study’s other findings was that average blood levels of the anti-inflammatory protein IL-1Ra, coded by IL1RN, were 14 times higher in 181 hospitalised men than in healthy male study controls from the general population, and 10 times as high in 178 hospitalised women than in healthy females. The increased levels of IL-1Ra in women did not result in any statistically significant mortality reductions.

“Our analysis offers substantial evidence of the biological link between the severe inflammation seen in SARS-CoV-2 and that which occurs in rheumatoid arthritis,” said study senior investigator Steven Abramson, MD, the Frederick H. King Professor of Internal Medicine at NYU Langone.

Abramson, a rheumatologist who also serves as chair of the Department of Medicine and chief academic officer at NYU Langone, says previous research has shown that such rheumatoid inflammation is lower in people who possessed one of the three IL1RN variants analysed in the study.

More importantly, Abramson says, the new research suggests that restraining the interleukin-1 biological pathway, which is in part tamped down by the anti-inflammatory protein IL-1Ra, could help prevent the severe inflammation seen in SARS-CoV-2 infection. Further research, he says, is warranted into whether IL-1-inhibiting therapies, such as the IL1 receptor antagonists anakinra, canakinumab, and rilonacept, are effective against Covid infection.

Abramson already has plans to investigate if the IL-1 pathway plays a role in long Covid, when people experience new or lingering symptoms, such as fatigue and ‘brain fog’, months after recuperating from their initial infection.

Abramson points out that the new study adds to the growing scientific evidence about the biological factors that contribute to gender differences seen in deaths from COVID, which are known to vary widely across the United States.

Source: NYU Langone Health / NYU Grossman School of Medicine

Categories : Diet and Nutrition Immune SystemTags :

Yet Another Impact of High-fat Diets: Immune Changes

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Photo by Patrick Fore on Unsplash

A new study from UC Riverside has added more reasons to stick to New Year’s diet resolutions: it showed that that high-fat diets affect genes linked not only to obesity, colon cancer and irritable bowels, but also to the immune system, brain function, and potentially COVID risk.

While other studies have examined the effects of a high-fat diet, this one is unusual in its scope. UCR researchers fed mice three different diets over the course of 24 weeks where at least 40% of the calories came from fat. Then, they looked not only at the microbiome, but also at genetic changes in all four parts of the intestines.

One group of mice ate a diet based on saturated fat from coconut oil, another got a monounsaturated, modified soybean oil, a third got an unmodified soybean oil high in polyunsaturated fat. Compared to a low-fat control diet, all three groups experienced concerning changes in gene expression, the process that turns genetic information into a functional product, such as a protein.

Plant-based or not, high-fat is bad

“Word on the street is that plant-based diets are better for you, and in many cases that’s true. However, a diet high in fat, even from a plant, is one case where it’s just not true,” said Frances Sladek, a UCR cell biology professor and senior author of the new study.

The study, published in Scientific Reports, documents the many impacts of high-fat diets. Some of the intestinal changes did not surprise the researchers, such as major changes in genes related to fat metabolism and the composition of gut bacteria. For example, they observed an increase in pathogenic E. coli and a suppression of Bacteroides, which helps protect the body against pathogens.

Other observations were more surprising, such as changes in genes regulating susceptibility to infectious diseases. “We saw pattern recognition genes, ones that recognise infectious bacteria, take a hit. We saw cytokine signalling genes take a hit, which help the body control inflammation,” Sladek said. ‘So, it’s a double whammy. These diets impair immune system genes in the host, and they also create an environment in which harmful gut bacteria can thrive.”

The team’s previous work with soybean oil documents its link to obesity and diabetes, both major risk factors for COVID. This paper now shows that all three high-fat diets increase the expression of ACE2 and other host proteins that are used by COVID spike proteins to enter the body.

Additionally, the team observed that high-fat food increased signs of stem cells in the colon. “You’d think that would be a good thing, but actually they can be precursors to cancer,” Sladek said.

In terms of effects on gene expression, coconut oil showed the greatest number of changes, followed by the unmodified soybean oil. Differences between the two soybean oils suggest that polyunsaturated fatty acids in unmodified soybean oil, primarily linoleic acid, play a role in altering gene expression.

Negative changes to the microbiome in this study were more pronounced in mice fed the soybean oil diet. This was unsurprising, as the same research team previously documented other negative health effects of high soybean oil consumption.

Soybeans are fine, but watch the oil

In 2015, the team found that soybean oil induces obesity, diabetes, insulin resistance, and fatty liver in mice. In 2020, the researchers team demonstrated the oil could also affect genes in the brain related to conditions like autism, Alzheimer’s disease, anxiety, and depression.

Interestingly, in their current work they also found the expression of several neurotransmitter genes were changed by the high fat diets, reinforcing the notion of a gut-brain axis that can be impacted by diet.

The researchers have noted that these findings only apply to soybean oil, and not to other soy products, tofu, or soybeans themselves. “There are some really good things about soybeans. But too much of that oil is just not good for you,” said UCR microbiologist Poonamjot Deol, who was co-first author of the current study along with UCR postdoctoral researcher Jose Martinez-Lomeli.

Also, the studies were conducted using mice, and mouse studies do not always translate to the same results in humans. However, humans and mice share 97.5% of their working DNA. Therefore, the findings are concerning, as soybean oil is the most commonly consumed oil in the United States, and is increasingly being used in other countries, including Brazil, China, and India.

By some estimates, Americans tend to get nearly 40% of their calories from fat, which mirrors what the mice were fed in this study. “Some fat is necessary in the diet, perhaps 10 to 15%. Most people though, at least in this country, are getting at least three times the amount that they need,” Deol said.

Readers should not panic about a single meal. It is the long-term high-fat habit that caused the observed changes. Recall that the mice were fed these diets for 24 weeks. “In human terms, that is like starting from childhood and continuing until middle age. One night of indulgence is not what these mice ate. It’s more like a lifetime of the food,” Deol said.

That said, the researchers hope the study will cause people to closely examine their eating habits.

Source: University of California – Riverside

Categories : Ageing COVIDTags :

Higher Oestrogen Levels Protect Older Women Against Severe COVID

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Photo by Ravi Patel on Unsplash

An older woman’s oestrogen levels may be linked to her chances of dying from COVID, with higher levels of the hormone seemingly protective against severe infection, according to a study published in BMJ Open.

Supplemental hormone treatment to curb the severity of COVID infection in post-menopausal women could be investigated, the researchers suggested.

Even after accounting for other factors, women seem to have a lower risk of severe COVID infection than men. This holds true for other serious recent viral infections, such as MERS (Middle East Respiratory Syndrome).

Oestrogen may have a role in this gender discrepancy, so to invesitgate the researchers compared the potential effects of boosting and reducing oestrogen levels on COVID infection severity.

They drew on Swedish national data, and the study sample included 14 685 women in total: 227 (2%) had been previously diagnosed with breast cancer and were on oestrogen blocker drugs (adjuvant therapy) to curb the risk of cancer recurrence; and 2535 (17%) were taking hormone replacement therapy (HRT) to boost their oestrogen levels in a bid to relieve menopausal symptoms.

Some 11,923 (81%) women acted as the comparison group as they weren’t on any type of treatment, either to enhance or reduce their systemic oestrogen levels.

Analysis of all the data showed that compared with no oestrogen treatment, the crude odds of dying from COVID were twice as high among women on oestrogen blockers but 54% lower among women on HRT.

After accounting for potentially influential factors, COVID mortality risk remained significantly lower (53%) for women on HRT.

Unsurprisingly, age was significantly associated with COVID mortality risk, with each extra year associated with 15% greater odds, while every additional coexisting condition increased the odds of death by 13%.

And those with the lowest household incomes were nearly 3 times as likely to die as those with the highest.

As an observational study, it cannot establish cause. There were no data on the precise doses of HRT or oestrogen blocker drugs, or their duration, nor on weight or smoking, while the number of women on adjuvant therapy was relatively small.

These factors may have been influential. But the researchers conclude: “This study shows an association between oestrogen levels and COVID death. Consequently, drugs increasing oestrogen levels may have a role in therapeutic efforts to alleviate COVID severity in postmenopausal women and could be studied in randomised control trials.”

Source: EurekAlert!

Categories : COVIDTags :

SARS-CoV-2: A ‘Predatory Virus’ That Raises All-cause Mortality Risk

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Source: CDC

SARS-CoV-2 is a “predatory virus” that appears to have multiplied the risk of death by a similar amount for most adults in the UK regardless of their underlying health status, according to new research published in PLOS Medicine.

The London School of Hygiene & Tropical Medicine (LSHTM)-led research team estimated excess mortality in the UK during Wave 1 of the COVID pandemic in nearly 10 million adults aged 40 and over. They then estimated and compared relative rates of all-cause mortality in people with and without more than 50 health and socio-demographic characteristics before the pandemic and during Wave 1.

The rate of death during Wave 1 increased on average by a factor of just over 40% (x1.4) for the study population compared to before the pandemic. This relative increase in the rate of death was surprisingly consistent across much of the population, regardless of health conditions and other characteristics.

However, before the pandemic, those with pre-existing health conditions such as heart disease or asthma had a higher mortality rate than those without a further mortality rate increase of 40% had a bigger absolute impact on them.

Exceptions included those with dementia and learning difficulties; both groups had approximately 3x the rate of death compared to people without the condition before the pandemic but approximately 5x the rate of death compared to people without the condition during Wave 1.

Non-white ethnicities were another exception: black people had 20% reduced rate of death compared to white people before the pandemic but a 50% increase in relative rate of death compared to white people during Wave 1. Also, those living in London also had a lower rate of death before the pandemic compared to people living outside of London, but substantially elevated relative rate during Wave 1.

Researcher co-leader, LSHTM’s Dr Helen Strongman, said: “Our work has shown that the threat posed by COVID increases evenly with frailty or ill health caused by ageing and a wide range of respiratory and non-respiratory medical conditions. This compares to flu, which also tends to be more dangerous in the elderly but also affects young children and is more strongly associated with respiratory conditions such as asthma, COPD and smoking.”

Whilst the health and demographic factors studied are known to be associated both with mortality in non-pandemic years and mortality due to COVID during the pandemic, this is the first time the two have been linked – analysing all-cause mortality rather than COVID-specific mortality. 

Dr Strongman said: “As we learn to live with COVID, we all need to be aware of and manage our own risk and that of others around us. Our study shows that SARS-CoV-2 is a predatory virus, amplifying mortality rates across the board, and having the biggest impact on those with existing ill health or who are frail. This emphasises how important it is for everyone to protect themselves and the most vulnerable in society through measures such as vaccination and wearing face masks. However, more basic research about why and how the virus exploits any vulnerability is needed.”

Dr Helena Carreira from LSHTM and co-lead author, added: “While we saw increases in the rate of death during the first wave of the pandemic across the population, our study also reinforced how COVID has disproportionately affected some groups, including people with dementia and learning disabilities, possibly through higher levels of exposure due to institutional or home-based care or occupation.”

Further research is needed to clarify whether there were differences across waves in the UK, especially for ethnicity, deprivation and other factors, and independent effects of individual health and demographic risk factors should be investigated.

Limitations include possible misclassification of the date of death for some individuals and the misclassification of health factors through incomplete information. However, the similarity of the results obtained from sensitivity analyses suggest only a minor impact on their findings.

Source: London School of Hygiene and Tropical Medicine

Categories : COVIDTags :

Scientist Identify the Gene Responsible for Doubling Severe COVID Risk

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Image source: Pixabay

Scientists at Oxford University have identified the gene responsible for doubling the risk of respiratory failure from COVID. Some 60% of people of South Asian descent carry the high-risk genetic signal, partly explaining the impact of COVID in the Indian subcontinent and the excess deaths seen in some UK communities.

Prior research already identified a stretch of DNA on chromosome 3 which doubled the COVID mortality risk of adults under 65. However, scientists did not know how this genetic signal worked to increase the risk, nor the exact genetic change that was responsible.

In a study published in Nature Genetics, an Oxford University team used cutting edge technology to work out which gene was causing the effect, and how it was doing so.

Study co-lead Jim Hughes, Professor of Gene Regulation, said: “The reason this has proved so difficult to work out, is that the previously identified genetic signal affects the ‘dark matter’ of the genome. We found that the increased risk is not because of a difference in gene coding for a protein, but because of a difference in the DNA that makes a switch to turn a gene on. It’s much harder to detect the gene which is affected by this kind of indirect switch effect.”

The team trained an artificial intelligence algorithm to analyse huge quantities of genetic data from hundreds of types of cells from all parts of the body, to show that the genetic signal is likely to affect cells in the lung. Then the researchers used a newly developed precision technique to zero in on the DNA at the genetic signal. This examines the way that the billions of DNA letters fold up to fit inside a cell to locate the specific gene that was being controlled by the sequence that increases severe COVID risk.

Dr Damien Downes, who led laboratory work, said: “Surprisingly, as several other genes were suspected, the data showed that a relatively unstudied gene called LZTFL1 causes the effect.”

The researchers found that the higher risk version of the gene probably prevents the cells lining airways and the lungs from responding to the virus properly. But importantly it doesn’t affect the immune system, so the researchers expect people carrying this version of the gene to respond normally to vaccines.

The researchers are also hopeful that drugs and other therapies could target the pathway preventing the lung lining from transforming to less specialised cells, raising the possibility of new treatments customised for those most likely to develop severe symptoms.

Study co-lead Professor James Davies, Associate Professor of Genomics at Oxford University, said: “The genetic factor we have found explains why some people get very seriously ill after coronavirus infection. It shows that the way in which the lung responds to the infection is critical. This is important because most treatments have focussed on changing the way in which the immune system reacts to the virus.”

About 60% of people with South Asian ancestry carried this higher-risk version of the gene compared to 15% of those with European ancestry – explaining in part the higher death rates and hospitalisations in the former group. The study also found that 2% of people with Afro-Caribbean ancestry carried the higher risk genotype, meaning that this genetic factor does not completely explain the higher death rates reported for black and minority ethnic communities.

Prof Davies explained: “The higher risk DNA code is found more commonly in some black and minority ethnic communities but not in others. Socioeconomic factors are also likely to be important in explaining why some communities have been particularly badly affected by the COVID pandemic.

“Although we cannot change our genetics, our results show that the people with the higher risk gene are likely to particularly benefit from vaccination. Since the genetic signal affects the lung rather than the immune system, it means that the increased risk should be cancelled out by the vaccine.”

Source: Oxford University

Categories : COVIDTags :

Air Pollution May Increase COVID Mortality Risk by 11%

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Air pollution, a persistent problem around the world, is known to cause lung diseases, and existing lung diseases are known to exacerbate COVID. According to new research reported on by The Guardian, air pollution has been shown to be a significant factor for dying from COVID – increasing the risk of death by 11%.

The gold standard for assessing an association between COVID and air pollution would be getting a large enough sample of participants and acquiring personal details so that their age, smoking history and other details can be taken into account. However, such levels of individual details are not yet available, so researchers are looking to group studies to provide the data, albeit at reduced quality. Hundreds of group studies are awaiting review, but the evidence so far appears compelling.

Prof Francesca Dominici at Harvard University, the research leader says that there is definitely enough evidence to act on already. “We already have an overwhelming amount of evidence of the adverse health effects of fine particle pollution, so even without Covid, we should implement more stringent regulation. But the amount of [Covid-related] evidence is also big enough now that there is absolutely nothing to lose, and only benefits, to prioritise some of the more vulnerable areas.”

Efforts to help mitigate the effect of air pollution on potential COVID patients could include air pollution reduction measures and distributing PPE in priority areas.