The immune defenses of the lungs weaken with age, making older adults more vulnerable to lung damage and severe respiratory infections.New research reveals one reason this might be happening: inhaling particulate matter from pollution Mess up the piece over timeweakens the immune system in the lungs, researchers report online Nov. 21 natural medicine.
air pollution is a Leading causes of disease and premature death worldwide and disproportionately Impacting Poor and Marginalized Communities (Serial Number: 7/30/20). Particulate matter—a pollutant emitted from vehicle exhaust, power plants, wildfires, and other sources—is linked to health hazards, including Respiratory, Cardiovascular and Neurological Diseases (Serial Number: 9/19/17).
In the new study, Columbia University researchers analyzed immune tissue from the lungs of 84 organ donors, ranging in age from 11 to 93 years old. Donors were never smokers or had no history of heavy smoking. The team found that with age, the lymph nodes in the lungs — which filter foreign matter and contain immune cells — become filled with particulate matter, turning them dark agate.
“if [lymph nodes] Elizabeth Kovacs, a cell biologist who studies inflammation and injury at the University of Colorado Anschutz School of Medicine in Aurora, said.
Lymph nodes are home to an array of immune cells, including macrophages. These Pac-Man cells engulf pathogens and other debris, including particulate matter. After being flooded with pollutants, macrophages produced fewer cytokines (proteins secreted by cells that activate other immune cells). The cells also showed signs of a reduced ability to swallow more food.
Kovacs, who was not involved in the research, said the new research suggests that older adults accumulate so much debris that “they may not be able to accumulate more,” impairing their ability to process inhaled substances.
Pollution “poses a continuing and growing threat to the health and livelihoods of the world’s population,” the team wrote. Threats, their work found, include “chronic and pervasive effects” on respiratory immunity as we age.
