Study Suggests Why influenza Risk Higher For Older People

(CTN NEWS) – The risk of viral influenza infections is higher in the elderly. A new study suggests an immune cell in the lungs may contribute to the explanation.

In the most recent issue of the Journal of Immunology, a team from Michigan Medicine and the Yale School of Medicine examined the impact of age on influenza-related mortality.

Senior author and director of the Michigan Biology of Cardiovascular Aging programme at the Frankel Cardiovascular Center Daniel Goldstein, MBBS, states,

“We discovered a mechanism by which ageing may result in greater vulnerability to influenza infection.”

Alveolar macrophages in the lungs are implicated in mortality with ageing.

According to a study by Goldstein’s team, including first authors Christine Wong of Yale and research fellow in internal medicine Candice Smith of the University of Michigan. They discovered it using infected mouse models.

“This study implies that medicines to enhance alveolar macrophage function may help older persons withstand influenza virus lung infection,” says Goldstein.

Starting at a disadvantage

As the lungs’ broom, the alveolar macrophages sweep up waste to ward off infection. However, compared to their younger counterparts, the aged mice’s lungs had fewer alveolar macrophages.

The equilibrium of the lungs depends on these cells.

According to Goldstein, a research professor at the Institute of Gerontology and the Eliza Maria Mosher Collegiate Professor in Internal Medicine,

“The transcriptional landscape of the cell is significantly affected by ageing, but we’re not sure why,” “We discovered the significant difference starts even before these lung cells become infected.”

Reduced alveolar macrophage numbers in advanced aged mice are likely caused by decreased cell turnover that comes with ageing, according to researchers.

But across all age groups, the number of alveolar macrophages in the lungs decreased after infection.

An impaired immune response

According to Goldstein, the previously healthy old mice had difficulty mounting an effective immune response to a fresh infection because of a lower alveolar macrophage count.

According to researchers, age has hampered a cellular absorption process, leading to what they have dubbed “defective phagocytosis.”

The study discovered that the advanced age group had a substantially greater mortality rate (80%) compared to the elderly (50%) and the young (0%) one week after contracting the influenza virus (25 percent).

Researchers discovered additional issues in the elderly, such as lung impairment and signs of inflammation. However, there was no discernible difference in the degree of organ damage between the age groups.

Increased retention of neutrophils, a class of white blood cells, was another effect of ageing. An abundance of neutrophils during an influenza virus infection will harm the lungs.

According to Goldstein, “this discovery shows that morbid complications from influenza  caused mortality, not systemic organ failure.”

“It shows that alveolar macrophages are less successful in preventing lung damage from the infection.”

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Future research, according to Goldstein, may look into ways to enhance alveolar macrophage function because doing so may improve the prognosis for elderly people afflicted with influenza and other respiratory viruses.

Goldstein’s team’s publication is consistent with two other earlier articles and related clinical studies that claim older persons had increased morbidity and death during an influenza illness, although it opposes the results of one recent study.

According to Goldstein, “the work emphasizes the importance and relevance of the mouse for understanding influenza with age.”

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