Breathing Air Pollution Particles Triggers Release of Inflammatory Cells From Bone Marrow
Researchers have shown that acute exposure to air pollution causes a systemic inflammation with an increase in white blood cells in the bloodstream in laboratory animals and in humans.
These white blood cells are infection-fighting cells that come from the bone marrow. The white blood cells that accumulate in the lung are predominantly monocytes (a type of white blood cell) released from the bone marrow. The function of these monocytes is to keep the lung clean by removing foreign material such as microorganisms and inhaled air pollution particles. The researchers postulate that exposure to air pollution induces the release of monocytes from the bone marrow, as part of the systemic inflammatory response to particulate air pollution.
This study was designed to explore these mechanisms in more detail. Researchers instilled two types of particles — inert carbon, and ambient PM10 into the lungs of rabbits, and measured bone marrow stimulation and the release of monocytes from the bone marrow.
The results showed that deposition of particulate matter into the lung stimulates the bone marrow to speed the release of white blood cells into the bloodstream. They also showed that the composition of the particles determines the magnitude of response.
“We suspect that these white cells such as monocytes released from the marrow by exposure to particulate matter air pollution contribute to the adverse health effects of air pollution on both the heart and lung,” researchers conclude.
Goto Y, Ishii H, Hogg JC, Shih C-H, Yatera K, Vincent R, van Eeden SF.
Particulate matter air pollution stimulates monocyte release from the bone
marrow. Am J Respir Crit Care Med 2004, In press. Published online ahead of print on July 15, 2004, doi:10.1164/rccm.200402-235OC.
The American Thoracic Society [ajrccm.atsjournals.org] offers the abstract online.
