The lungs’ immune defenses can wane with age, leaving older adults more susceptible to lung damage and severe bouts of respiratory infections. A new study reveals that inhaled particulate matter (pollution) could be one reason for this. Keep the works in good shape over time, weakening the lungs’ immune system, researchers report online November 21 in Nature Medicine.
The main cause of air pollution is Early death is a major cause of illnessGlobally and indisproportionate numbers It has an impact on the poor and marginalized (SN: 7/30/20). Particulate matter — a type of pollution emitted from vehicle exhaust, power plants, wildfires and other sources — has been tied to health harms including Neurological, cardiovascular, respiratory and cardiovascular diseases (SN: 9/19/17).
Columbia University researchers analyzed the lung immune tissue of 84 organ donors. They ranged from 11 to 93 year old. The donors had not smoked or had a history of heavy smoking. With age, the lungs’ lymph nodes — which filter foreign substances and contain immune cells — became loaded with particulate matter, turning them a deep onyx, the research team found.
“If the [lymph nodes] build up with so much material, then they can’t do their job,” says Elizabeth Kovacs, a cell biologist who studies inflammation and injury at the University of Colorado Anschutz Medical Campus in Aurora.
A variety of immune cells reside in the lymph nodes, including macrophages. These cellular Pac-Mans consume pathogens and other debris including particulate matter. Filled with the pollutant, the macrophages’ production of cytokines, proteins the cells secrete to activate other immune cells, decreased. There were also signs that the cells had a reduced capacity to consume more gobbling.
The new study indicates that older people have accumulated so much debris, “they may not be able to accumulate more,” impairing their ability to deal with inhaled material, says Kovacs, who was not involved in the research.
Pollution “is an ongoing and growing threat to the health and livelihood of the world’s population,” the research team writes. Their work finds that threat includes “a chronic and ubiquitous impact” on respiratory immunity with age.
