Study hints at why older people are more susceptible to the flu

Influenza is back in circulation, posing a special danger to older adults.

12:05 PM

Author | Kelly Malcom

senior woman blowing nose blanket
Getty Images

Though the COVID-19 pandemic provided a brief respite, influenza virus is back in circulation and, as usual, poses a special danger to people over the age of 65. But why are older people more susceptible to the flu? Research from the University of Michigan Medical School, published in Nature Communications, offers clues.

The study, led by first author Judy Chen, a Ph.D. candidate, senior author Daniel Goldstein, M.D., the Eliza Maria Mosher Collegiate Professor in Internal Medicine and professor of Microbiology and Immunology, and their team investigates why cells called alveolar macrophages, the first line of defense in the lungs, appear to be compromised with age.

These macrophages are immune cells that attack invaders like the flu virus and live in the small air sacs, or alveoli, inside the lungs. Importantly, these cells appear to be lost with aging.

Like Podcasts? Add the Michigan Medicine News Break on Spotify, Apple Podcasts or anywhere you listen to podcasts.

Previous research by another group showed that when macrophages from an old mouse were put into a young mouse, and cells looked young again. "This drove us to believe that something in the environment of the lungs is contributing to this," said Chen.

Signs pointed to a lipid immune modulator known as prostaglandin E2 (PGE2) with wide ranging effects, from labor induction in pregnancy to inflammation with arthritis. The study team discovered there is more PGE2 in the lungs with age. This increase in PGE2, Chen explained, acts on the macrophages in the lung, limiting their overall health and ability to generate.

The team suspects that the buildup of PGE2 is yet another marker of a biological process called senescence, which is often seen with age. Senescence serves as insurance against the runaway division of damaged cells; cells that are senescent are no longer able to replicate.

"One of the interesting things about these cells is they secrete a lot of inflammatory factors," said Chen.

The study showed that with age, the cells lining the air sacs in the lungs become senescent, and these cells lead to increased production of PGE2 and suppression of the immune response.

To test the link between PGE2 and increased susceptibility to influenza, they treated older mice with a drug that blocks a PGE2 receptor. "The old mice that got that drug actually ended up having more alveolar macrophages and had better survival from influenza infection than older mice that did not get the drug," said Chen.

The team plans to next investigate the various ways PGE2 affects lung macrophages as well as its potential role in inflammation throughout the body. "As we get older, we become more susceptible not only to influenza, but to other infections, cancers, autoimmune diseases as well."

Live your healthiest life: Get tips from top experts weekly. Subscribe to the Michigan Health blog newsletter

Headlines from the frontlines: The power of scientific discovery harnessed and delivered to your inbox every week. Subscribe to the Michigan Health Lab blog newsletter

Paper cited: "Age-induced prostaglandin E2 impairs mitochondrial fitness in alveolar macrophages and increases mortality to influenza infection." Nature Communications. DOI: 10.1038/s41467-022-34593-y


More Articles About: Body Work Basic Science and Laboratory Research Flu Community Health Geriatrics Immunizations All Research Topics
Health Lab word mark overlaying blue cells
Health Lab

Explore a variety of healthcare news & stories by visiting the Health Lab home page for more articles.

Media Contact Public Relations

Department of Communication at Michigan Medicine

[email protected]

734-764-2220

Stay Informed

Want top health & research news weekly? Sign up for Health Lab’s newsletters today!

Subscribe
Featured News & Stories Mott Poll teens and caffeine
Health Lab
Does your teen consume too much caffeine?
A quarter of parents report that caffeine is basically part of their teen’s daily life, according to a national poll.
pills floating blue pink dark background physician in middle looking at chart white coat scrubs
Health Lab
Better medical record-keeping needed to fight antibiotic overuse, studies suggest
Efforts to reduce overuse of antibiotics may be hampered by incomplete medical records that don’t show the full reasons for prescriptions.
surgery gloves passing tool blue and yellow
Health Lab
A universal heparin reversal drug is shown effective in mice
The newest version of the heparin reversal drug, described in a recent issue of Advanced Healthcare Materials, adjusted the number of protons bound to it, making the molecule less positive so it would preferentially bind to the highly negative heparin, resulting in a much safer drug.
zoom screens with 7 different backgrounds and doctor silhouettes outlined in each
Health Lab
The doctor is in…. but what’s behind them?
A study reveals that what a doctor has behind them during a telehealth visit can make a difference in how the patient feels about them and their care.
teal persons body looks like a puzzle red heart top right of shoulder and chest getting placed into missing piece spot
Health Lab
Normothermic perfusion system extends life of organs waiting for transplant
A team of researchers have spent the past eight years looking at better ways to transport organs for donation, specifically hearts, to improve the number of organs that can be used for transplants. They found that using a modified normothermic perfusion system heart preservation was feasible for up to 24 hours.
blue gloves in hospital hanging IV bag
Health Lab
Commonly used antibiotic brings more complications, death in the sickest patients
In emergency rooms and intensive care units across the country, clinicians make split-second decisions about which antibiotics to give a patient when a life threatening infection is suspected. Now, a study reveals that these decisions may have unintended consequences for patient outcomes.