|Ibuprofen can lower lung inflammation with age.|
New research, published in the Journal of Leukocyte Biology, shows that the lungs become more inflammatory with age and that ibuprofen can lower that inflammation. In fact, immune cells from old mouse lungs fought tuberculosis bacteria as effectively as cells from young mice after lung inflammation was reduced by ibuprofen. The ibuprofen had no effect on the immune response to TB in young mice.
Most previous research establishing inflammation's links to aging and disease has tested blood for elevated proteins that signal an inflammatory environment. These researchers found the same proteins in the lungs of old mice. Research has already established that the inevitable inflammation that comes with aging is linked to such conditions as Type 2 diabetes and heart disease.
Though this line of work might someday support the use of ibuprofen as an adjunct therapy for elderly people with TB, the researchers are not recommending use of the drug for the purposes of lowering inflammation.
In this new study, the researchers compared lung cells from old and young mice and found that in the old mice, genes that make three classic pro-inflammatory proteins, called cytokines, were more active in the lungs of old mice. The cytokines are interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-a). In addition, immune system cells called macrophages in the lungs from old mice were in an advanced state of readiness to fight an infection, a status that signals inflammation. Macrophages in young mouse lungs were in a normal, resting state.
In test tubes, the scientists exposed mouse lung macrophages to TB bacteria. The macrophages from old mouse lungs were quicker to absorb the bacteria than were immune cells from young mice, but that initial robust immune response from the cells of old mice could not be sustained.
Though some elements of the elderly response to TB remain a mystery, this finding suggested that the inflammation in the lungs of elderly mice had the direct effect of reducing the long-term effectiveness of their immune response to TB infection. Old mice in the study were 18 months old – equivalent to about 65 in human years, and young mice were 3 months old, a similar age to human young adults.
The researchers gave old and young mice ibuprofen in their food for two weeks and then examined their lung cells. After this diet modification, several pro-inflammatory cytokines in the lungs of old mice had been reduced to levels identical to those in the lungs of young mice, and the macrophages in old mouse lungs were no longer in a primed state.
The researchers have extended the work to test whether ibuprofen affects the elderly mouse immune response to TB infection.