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Circulation. 2002 ; 105 : 411.
2002 American Heart Association, Inc .
        Passage of Inhaled Particles Into the Blood Circulation in Humans

A. Nemmar, DVM, PhD; P.H.M. Hoet, PhD; B. Vanquickenborne, MD; D. Dinsdale, PhD; M. Thomeer, MD; M.F. Hoylaerts, PhD; H. Vanbilloen, PhD; L. Mortelmans, MD, PhD; B. Nemery, MD, PhD

From the Laboratory of Pneumology (Lung Toxicology) (A.N., P.H.M.H., M.T., B.N.), Nuclear Medicine (B.V., H.V., L.M.), and Center for Molecular and Vascular Biology (M.F.H.), Katholieke Universiteit Leuven,  Belgium; and the MRC Toxicology Unit (D.D.), Leicester, UK.

Background -  Pollution by particulates has been consistently associated with increased cardiovascular morbidity and mortality. However, the mechanisms responsible for these effects are not well-elucidated.

Methods and Results - To assess to what extent and how rapidly inhaled pollutant particles pass into the systemic circulation, we measured, in 5 healthy volunteers, the distribution of radioactivity after the inhalation of "Technegas," an aerosol consisting mainly of ultrafine 99mTechnetium-labeled carbon particles (<100 nm). Radioactivity was detected in blood already at 1 minute, reached a maximum between 10 and 20 minutes, and remained at this level up to 60 minutes. Thin layer chromatography of blood showed that in addition to a species corresponding to oxidized 99mTc, ie, pertechnetate, there was also a species corresponding to particle-bound 99mTc. Gamma camera images showed substantial radioactivity over the liver and other areas of the body.

Conclusions - We conclude that inhaled 99mTc-labeled ultrafine carbon particles pass rapidly into the systemic circulation, and this process could account for the well-established, but poorly understood, extrapulmonary effects of air pollution.