The immune defenses of the lungs can decline with age, leaving older adults more susceptible to lung damage and serious bouts of respiratory infections. New research points to one reason why this happens: Particulate matter inhaled by dirt gunks works over time to undermine the lung’s immune system, researchers report online Nov. 21. Nature Medicine.
Air pollution is a major cause of disease and early death, which is ubiquitous and disproportionately impacts poor communities and the margins of society.SN: 7/30/20). Particular matter – the type of pollution emitted from vehicle exhaust, potential vegetation, fires and other sources, combined with harm to health including respiratory, cardiovascular and neurological diseases.SN: 9/19/17).
In a new study, researchers from Columbia University analyzed lung tissue from 84 organ donors, ranging in age from 11 to 93 years old. Donors were nonsmokers or had no history of heavy smoking. With age, the lymph nodes of the lungs—which disperse foreign substances and contain immune cells—become loaded with particular material, turning them off, the research team found.
“If” [lymph nodes] with so much material to build up, 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.
Lymph nodes are home to organized immune cells, including macrophages. These cellular PAC-Mans shed pathogens and other debris with particular material. Filled with pollutants, macrophages have decided to produce cytokines, proteins secreted by cells to stimulate other immune cells. The cells also showed signs of a decreased capacity to flush out more.
A new study shows that older people have accumulated so much debris, “that they can’t accumulate more,” hampering their ability to deal with the material they’ve ingested, says Kovacs, who wasn’t involved in the research.
Pollution is a “persistent and growing threat to the health and lives of people around the world,” the research team writes. Their work found threats that include a “chronic and ubiquitous impact” on respiratory immunity with age.
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