The cells in the noses of kids and older adults react differently to the SARS-CoV-2 virus, which could be why children tend to have less severe COVID-19 symptoms, according to a recent study. The research, led by UCL and the Wellcome Sanger Institute, was published in Nature Microbiology and looked at the initial impact of SARS-CoV-2 infection on the cells.The human nasal epithelial cells (NECs) were the focus of the study, with participants from Great Ormond Street Hospital (GOSH), University College London Hospital (UCLH), and the Royal Free Hospital donating the cells. This included a range of ages, from children (0-11 years) to adults (30-50 years) and, for the first time, the elderly (over 70 years). Through specialized techniques, the cells were cultured and regrown into the various types of cells found in the nose. Single-cell RNA sequencing techniques were then used to identify the unique genetic networks and functions of thousands of individual cells.In a study of nasal epithelial cells, the team discovered 24 different types of epithelial cells. Cultures from different age groups were then either mock infected or infected with SARS-CoV-2.
The team observed that, after three days, the nasal epithelial cells (NECs) of children responded rapidly to SARS-CoV-2 by increasing interferon, the body’s first line of defense against viruses, which helped limit viral replication. However, this early antiviral effect became less effective with age.
Furthermore, the researchers found that NECs from elderly individuals not only produced more infectious virus particles, but also experienced increased cell shedding and damage.
This strong antiviral response was much more pronounced in the NECs of children compared to those of elderly individuals.The differences in nasal epithelial cells (NECs) between children and the elderly could be the reason why younger people tend to have less severe symptoms. On the other hand, the increased damage and higher viral replication in NECs from older individuals may be connected to the more severe disease observed in this age group.
Dr. Claire Smith, the leader of the project and an Associate Professor at UCL Great Ormond Street Institute of Child Health, stated: “Our research shows how the composition of cells in our nose changes as we age, and how this impacts our ability to fight SARS-CoV-2 infection. This could be crucial for developing effective antiviral treatments tailored to different age groups.”
The study found that SARS-CoV-2 infections affect different age groups differently, with the elderly being at higher risk of severe COVID-19.
Dr. Kerstin Meyer, one of the authors of the study, explained that by infecting epithelial cells with SARS-CoV-2 in vitro and studying their responses using single cell sequencing, the researchers gained a more detailed understanding of the viral infection kinetics and observed significant differences in the innate immune response between different types of cells.
While children infected with SARS-CoV-2 rarely experience respiratory failure, the risk of mortality in individuals over the age of 85 remains high, despite being vaccinated and improvements in medical care.treatment options.
The study highlights the significance of age as a crucial factor in both the research and treatment of infectious diseases.
Dr Marko Nikolic (UCL Division of Medicine), who is a co-senior author, commented on the findings, stating, “It is interesting that even when we remove immune cells from nasal samples and are left with only nasal epithelial cells grown in a dish, we can still observe age-specific differences in how our bodies respond to SARS-CoV-2 in the young and elderly, which helps explain why children are generally less susceptible to severe COVID-19.”
Dr Smith further explained, “Understanding the cellular variations at The exploration of the ramifications of cellular changes resulting from the infection is the initial stage of our investigation. Our aim now is to delve into the potential long-term effects of these alterations and to develop and assess therapeutic approaches using our distinctive cell culture model. The establishment of this high-quality system is made possible by the support of our sponsors and the willingness of participants to provide their samples.
The team proposes that future studies should take into account how the aging process influences the body’s response to various viral infections.
Funding for this research was provided by UK Research and Innovation (UKRI), as well as the National Institute for Health and Care Research (NIHR) Great Ormond Street Hospital Biomedical Research Centre, Wellc.The study was conducted by researchers from various institutions including University College London, Great Ormond Street Hospital, University of Cambridge, and the Chan Zuckerberg Foundation.