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Neutrophils and low-grade inflammation in the seemingly normal aging human lung
K C Meyer1, N S Rosenthal, P Soergel
1Department of Medicine, H6/380 Clinical Sciences Center, Madison, WI 53792, USA. kcm@medicine.wisc.edu
Mechanisms of Ageing and Development
|October 29, 1998
Summary
Aging lungs show increased neutrophils in the lower respiratory tract, indicating low-grade inflammation in healthy older adults. This age-related lung inflammation is linked to changes in inflammatory markers.
Area of Science:
- Pulmonology
- Gerontology
- Immunology
Background:
- Lung function declines with age, associated with elastin loss and reduced elastic recoil.
- Neutrophil accumulation in the lower respiratory tract may contribute to age-related lung changes.
Purpose of the Study:
- To investigate if older, healthy individuals have increased neutrophils in their lower airways.
- To examine age-related differences in inflammatory markers within the respiratory tract.
Main Methods:
- Bronchoalveolar lavage (BAL) was performed on three age groups: young (19-36), middle-aged (45-55), and older adults (64-83).
- Neutrophil counts, interleukin-8 (IL-8), neutrophil elastase (NE), alpha1-antiprotease, and elastase inhibitory capacity (EIC) were measured in BAL fluid.
Main Results:
- Neutrophil counts were significantly higher in the oldest group (64-83 years) compared to the youngest group (19-36 years).
- Levels of IL-8 and NE complexed to alpha1-antiprotease were also significantly elevated in older adults.
- Levels of alpha1-antiprotease and EIC were increased in the oldest age group.
Conclusions:
- Clinically normal, older individuals exhibit evidence of low-grade airway inflammation.
- Increased neutrophils and inflammatory mediators in the lower respiratory tract may be a feature of aging lungs.