Research Roundup: COVID-19 Severity and Later Respiratory Problems and More
Every week there are numerous scientific studies published. Here’s a look at some of the more interesting ones.
Initial COVID-19 Severity Not Linked to Later Respiratory Problems
Researcher Liam Townsend and colleagues at the Department of Infectious Diseases, St. James’s Hospital and Department of Clinical Medicine, Trinity Translational Medicine Institute, Trinity College, Dublin, Ireland, studied the lung function recovery and overall health of people who had varying degrees of COVID-19 severity. The results were published in the Annals of the American Thoracic Society.
“We found that fatigue, ill-health and breathlessness were all common following COVID-19,” said Townsend. “However, these symptoms appeared to be unrelated to the severity of initial infection or any single measurement at the time of an outpatient appointment.”
They graded patients’ initial infection severity in 3 categories: 1, not requiring hospital admission; 2, requiring hospital admission; and 3, requiring ICU care. About half of the patients evaluated required hospital admission during acute infection. They then analyzed the link between the initial disease and abnormal chest x-ray, six-minute walk test distance, and perception of maximal exertion during follow-up appointments. Patients were also questioned about whether they felt fatigue and if they believed they were completely healthy. Of the patients, 62% felt they had not returned to full health and 47% were classified as having fatigue.
“We were surprised by our findings,” Townsend said. “We expected a greater number of abnormal chest x-rays. We also expected the measures of ongoing ill-health and abnormal findings to be related to severity of initial infection, which was not the case.”
Milestone in Leishmaniasis Vaccine Development
Leishmaniasis is a parasitic disease found in some of the tropics, subtropics and southern Europe. Caused by infection with Leishmania parasites, which are spread by the bite of phlebotomine sand flies, there are many forms, but the most common are cutaneous, which causes skin sores, and visceral, which affects several internal organs, such as the spleen, liver and bone marrows. Researchers at the University of York have made a big step in developing a vaccine against leishmaniasis. What they did was identify and characterize a new strain of Leishmania that will be used in controlled human studies of infection. This type of model has been used to accelerate vaccines for cholera, malaria, typhoid, influenza and other infectious diseases. The next stage is recruiting healthy volunteers to determine how the body responds to the parasite.
How Viruses Become Infectious
Investigators with the University of Leeds have identified for the first time how viruses like the poliovirus and the common cold virus “package” their genetic code in a way that allows them to infect cells. The process, which has been known for a while, involves the creation of virions, which are newly formed infectious copies of the virus. Each virion has a protein shell that holds a complete copy of the virus’s genetic code. They then infect other cells. But what has been unknown to date is exactly how the virus assembles the virions. The study detailed how RNA packaging signals, which are short regions of the RNA molecule, work with proteins from the virus’s casing. They identified possible sites on the RNA molecule that could act as packaging signals.
Biomarkers in Father’s Sperm Associated with Children with Autism
Scientists at Washington State University identified biomarkers in human sperm that are associated with an increased likelihood of fathering children with autism spectrum disorder. They are epigenetic markers involved in regulating genome activity. The methylation regions are parts of the chromosomes that have additional methyl groups—a carbon atom with three hydrogen atoms attached—that act as molecular switches, turning gene expression on or off based on different environmental factors. Having identified a set of genomic features called DNA methylation regions, they created a series of blind tests and were able to determine if men had fathered autistic children with 90% accuracy. The team identified 805 different DNA methylation regions that can possibly be used as an epigenetic biomarker for susceptibility to father autistic offspring.
The Difference Between Regular Pneumonia and COVID-19 Pneumonia
A study out of Northwestern University describes how COVID-19 pneumonia differs from typical pneumonia caused by other diseases, such as bacteria or other viruses, such as influenza. Most lung infections that cause pneumonia rapidly spread throughout large regions of the lung. SARS-CoV-2, the virus that causes COVID-19, infects multiple small areas of the lung, then hijacks the lungs’ own immune cells. Using these immune cells, SARS-CoV-2 spreads across the lung over a period of days or weeks. And as it spreads slowly across the lung, it leaves damaged cells and tissue behind, which stimulates the fever, low blood pressure and damage to other organs, such as kidneys, brain and heart. The authors indicate that it is possible that the complications associated with COVID-19 compared to other types of pneumonia may be linked to the longer course of disease instead of more severe disease. They also identified critical targets to treat severe COVID-19 pneumonia, including macrophages and T-cells, which are immune cells.
Severe COVID-19 Associated with Short Telomeres
Telomeres are structures that protect the ends of chromosomes and their length is an indicator of aging. Each time a cell divides, telomeres shorten. It has already been observed that one of the causes of COVID-19 is damage to telomeres in cells involved in regenerating lung tissue, the alveolar type II pneumocytes—the cells that the SARS-CoV-2 coronavirus infects in lung tissue. Researchers at the Spanish National Cancer Research Centre (CNIO) in collaboration with the COVID-IFEMA Field Hospital, published research suggesting that people with short telomeres that are infected may have difficulty with lung tissue regeneration—which would likely explain why the disease hits the elderly so much harder than the young. However, one of the findings was also that the telomeres of the most seriously sick patients were also shorter, regardless of age. It’s not yet clear if the disease shortens telomeres, or whether the people most seriously affected, regardless of age, have shorter telomeres.
The researchers write, “Given that short telomeres can be made longer again by telomerase and given that in previous studies we have shown that telomerase activation has a therapeutic effect on diseases related to short telomeres, such as pulmonary fibrosis, it is tempting to speculate that this therapy could improve some of the pathologies that remain in COVID-19 patients once the viral infection has been overcome, such as pulmonary fibrosis.”