AJP - Lung Journal of Applied Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Lung Cell Mol Physiol 279: L924-L931, 2000;
1040-0605/00 $5.00
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (28)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mukae, H.
Right arrow Articles by van Eeden, S. F.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mukae, H.
Right arrow Articles by van Eeden, S. F.
Vol. 279, Issue 5, L924-L931, November 2000

Phagocytosis of particulate air pollutants by human alveolar macrophages stimulates the bone marrow

Hiroshi Mukae1, James C. Hogg1, Dean English1, Renaud Vincent2, and Stephan F. van Eeden1

1 Pulmonary Research Laboratory, University of British Columbia, St. Paul's Hospital, Vancouver, British Columbia V6Z 1Y6; and 2 Environmental Health Directorate, Health Canada, Ottawa, Ontario, Canada K1A OL2


    ABSTRACT
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

Epidemiologic studies have shown an association between the level of ambient particulate matter < 10 µm (PM10) and cardiopulmonary mortality. We have shown that exposure of rabbits to PM10 stimulates the bone marrow. In this study, we determined whether human alveolar macrophages (AMs) that phagocytose atmospheric PM10 produce mediators capable of stimulating the bone marrow. AMs incubated with PM10 for 24 h produced tumor necrosis factor-alpha in a dose-dependent manner (86.8 ± 53.29 pg/ml with medium alone; 1,087.2 ± 257.3 pg/ml with 0.1 mg/ml of PM10; P < 0.02). Instillation of the supernatants from AMs incubated with 0.1 mg/ml of PM10 into the lungs of rabbits (n = 6) increased circulating polymorphonuclear leukocyte (PMN) and band cell counts as well as shortened the PMN transit time through the bone marrow (87.9 ± 3.3 h) compared with unstimulated human AMs (104.9 ± 2.4 h; P < 0.01; n = 5 rabbits). The supernatants from rabbit AMs incubated with 0.1 mg/ml of PM10 (n = 4 rabbits) caused a similar shortening in the PMN transit time through the bone marrow (91.5 ± 1.6 h) compared with human AMs. We conclude that mediators released from AMs after phagocytosis of PM10 induce a systemic inflammatory response that includes stimulation of the bone marrow.

particulate matter less than 10 micrometers; air pollution; bone marrow; leukocytes; cytokines


    INTRODUCTION
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

EPIDEMIOLOGIC STUDIES HAVE associated particulate air pollution, especially particulate matter < 10 µm (PM10), with increased cardiopulmonary morbidity and mortality (6, 24). Residents of communities exposed to high levels of PM10 showed faster rates of lung function decline (19), more hospital admissions for pneumonia, chronic obstructive lung disease, myocardial infarctions, and heart failure after adjustment for several individual risk factors including smoking (1, 7, 20). The biological mechanisms responsible for this PM10-induced pulmonary and cardiovascular morbidity and mortality are not clear (33). Weiss et al. (36) have shown that an increase in peripheral blood leukocyte count is a predictor of total mortality, independent of smoking in large population-based studies, and several independent longitudinal studies (8, 9, 12) have linked elevations of the peripheral blood leukocyte count to increased mortality. A leukocytosis, specifically a granulocytosis, serves as a marker of the systemic inflammatory response (13) and is thought to contribute to this increase in morbidity and mortality. During an episode of acute air pollution in Southeast Asia, Tan et al. (26) demonstrated a leukocytosis in young military recruits that was associated with a release of granulocytes from the bone marrow (26). This suggests that this systemic inflammatory response that includes bone marrow stimulation is a feature of breathing polluted air and that this leukocyte response may play a pathogenetic role in the cardiopulmonary mortality associated with air pollution.

Our laboratory has developed a method to measure the response of the bone marrow in rabbits with the thymidine analog 5-bromo-2'-deoxyuridine (BrdU) to label dividing polymorphonuclear leukocytes (PMNs) in the bone marrow. This method provides the measurement of the transit time of PMNs through the mitotic and postmitotic pools of the bone marrow (27) and has been used to measure the effect of inflammatory stimuli such as pneumococcal pneumonia (27), cigarette smoking (28), glucocorticoids (17), and interleukin (IL)-8 (30) on the transit time of PMNs through the marrow pools. This model has also been used to show that the deposition of inert carbon particles in the lung enhanced the transit of PMNs through the bone marrow (18). Alveolar macrophages (AMs) were implicated in this response by showing that a similar stimulation of the marrow by supernatants from AMs fed carbon particles (29). Because AMs are important effector cells that phagocytose and process inhaled particles, we suspect that they play a key role in this bone marrow response. The present study was designed to determine whether mediators released from human AMs after phagocytosis of particles causes a systemic response that includes stimulation of the bone marrow. Mediators that could be responsible for this systemic response include granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, IL-1, and tumor necrosis factor (TNF)-alpha (14, 18). In the present study, we used TNF-alpha as a marker of human AM stimulation and the rabbit model to determine the collective effect of the AM-derived mediators on the bone marrow. A major question that we addressed in this study is whether the rabbit model we used to study bone marrow stimulation is suitable to study the effect of mediators produced by human AMs. We provide data showing that when human AMs phagocytose atmosphere-derived PM10, they release mediators that stimulate the bone marrow of rabbits. We propose that a rabbit model could be a useful tool in identifying the AM-derived mediators responsible for the systemic response to breathing polluted air.


    METHODS
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

Urban air particles. The urban air dust preparation EHC-93 was obtained from Environmental Health Directorate (Health Canada, Ottawa, ON) (34, 35). The particles were recovered from bag-house filters of the single-pass air filtration system of the Environmental Health Center in Ottawa (100% outdoor air), and their elemental and organic contents have been reported elsewhere (35). The dispersed particles have a mass median diameter of 4-5 µm, and 20% of the mass is associated with the fraction of particulate matter < 2.5 µm based on chemical profile and size distribution (34). The particles have a low direct cytotoxicity to lung macrophages (2) and contain endotoxin levels well below those detected in similar preparations such as SRM-1649 (3).

Stimulation of AMs in vitro. Human AMs were harvested from bronchoalveolar lavage (BAL) fluid from lungs resected for small peripheral tumors (n = 6 patients). All patients were smokers aged 62 ± 5 yr (3 women and 3 men). The BAL fluid was obtained from a noninvolved segment or lobe of the resected lung. Human AMs harvested from BAL fluid were >90% viable (trypan blue exclusion method) and consisted of 98% AMs and 2% lymphocytes and neutrophils (as determined by morphological identification of the cells by a qualified pathologist). Rabbit AMs were harvested by BAL from the lungs of normal 6-wk-old rabbits. After the rabbit was killed with pentobarbital sodium, a polyethylene tube was inserted into the trachea, and the lungs were washed with 50 ml of saline. More than 98% of cells recovered were AMs, and the cells were >90% viable. All specimens were tested for possible endotoxin contamination (positive specimens were excluded) with the Limulus amebocyte lysate test (detection level of 0.1 endotoxin unit/ml; E-TOXATE, Sigma, St. Louis, MO). Human and rabbit AMs were incubated with different concentrations of EHC-93. EHC-93 (0.01-0.1 mg/ml) particles were suspended in RPMI 1640 medium and 10% fetal calf serum. Cells (0.5 × 106/ml) were incubated with the PM10 suspension at 37°C in 5% CO2 for 24 h in a 24-well plate. This time point was selected after a time-series experiment in which supernatants were harvested 2, 4, 8, 12, and 24 h after EHC-93 exposure. AMs only at the 24-h time point were significantly different from control AMs incubated only with RPMI 1640 medium. The supernatants were harvested, and to remove all particulate matter from the supernatants, they were filtered through 0.2-µm filters and centrifuged at 180 g for 10 min before storage at -70°C. TNF-alpha levels in the supernatants were determined by ELISA with a commercially available kit (Genzyme Diagnostics, Cambridge, MA). The supernatants used for the in vivo studies (see Effect of mediators from AMs on the bone marrow: experimental protocol) were generated by incubating AMs with either RPMI 1640 medium (control group) or 0.1 mg/ml of PM10.

Effect of mediators from AMs on the bone marrow: experimental protocol. Female New Zealand White rabbits (weight 2.3-2.8 kg; n = 19) were used, and all studies were approved by the Animal Experimentations Committee of the University of British Columbia (Vancouver, BC).

BrdU (100 mg/kg; Sigma) was administered to rabbits 24 h before the intrabronchial instillation of the supernatants by infusion through the marginal ear vein at a concentration of 15 mg/ml in normal sterile saline over a period of 5 min (29). For bronchial instillation of the supernatants, the rabbits were anesthetized with ketamine hydrochloride (80-100 mg/kg intramuscularly) and xylazine (10-15 mg/kg intramuscularly) and challenged with intrabronchial instillation of supernatants (0.6 ml/kg) from either human AMs stimulated with PM10 or rabbit AMs stimulated with PM10. The supernatant was instilled in the lower lobe of the lung under fluoroscopic control by inserting a pediatric nasogastric tube through the trachea (29). The peripheral blood samples were obtained from the central ear artery just before the BrdU injection and 3, 6, 9, 12, 24, 36, 48, 72, 96, 120, 144, and 168 h after the intrabronchial instillation. One milliliter of blood was collected in standard Vacutainer tubes containing EDTA (Becton Dickinson, Rutherford, NJ) for leukocyte counts, and an additional 1 ml was collected in tubes containing acid citrate-dextrose for the detection of BrdU-labeled PMNs (PMNBrdU). Fentanyl (0.02 mg/kg) and droperidol (1.0 mg/kg) were used subcutaneously as sedation at each time point of blood collection.

The animals were killed with an overdose of pentobarbital sodium, the chests were opened rapidly, the base of the heart was ligated, and the lungs were removed and inflated at 25 cmH2O by intratracheal instillation of 10% phosphate-buffered Formalin for histological evaluation. The tissue blocks were sectioned (3 µm thick) and stained with hematoxylin and eosin. The tissue sections were evaluated at ×400 magnification in computer-generated random fields of view with a light microscope (Nikon, Japan, Tokyo).

Total white blood cell counts were determined on a model SS80 Coulter Counter (Coulter Electronics, Hialeah, FL). Differential counts were obtained by counting 100 leukocytes in randomly selected fields of view on Wright-stained blood smears, and 100 PMNs were evaluated in randomly selected fields of view to determine the changes in the number of band cells. Blood collected in acid citrate-dextrose was used to obtain leukocyte-rich plasma as previously described in detail (27). Leukocyte-rich plasma was cytospun onto 3-aminopropyltriethoxysilane-coated slides by cytocentrifugation at 180 g with a Cytospin 2 (Shandon Lab Products, Cheshire, UK) for 5 min. The cytospin specimens were air-dried and stained with the alkaline phosphatase-anti-alkaline phosphatase method to determine the fraction of PMNBrdU in each specimen as previously described (27).

Evaluation of PMNBrdU. PMNBrdU were evaluated as previously described (27). Briefly, PMNBrdU were divided into three groups according to the intensity of nuclear staining with an arbitrarily designated grading system. This grading system was designed to evaluate the transit time of the myeloid cells that were in their last division in the mitotic pool when exposed to BrdU (G3), those that were in the middle (G2), and those that were in their first division (G1). These slides were coded and examined without knowledge of the group or sampling time. Fields were selected in a systematic randomized fashion, and 200 cells were evaluated per specimen.

Transit time of PMNBrdU through the bone marrow was calculated as previously described (27). Briefly, the number of PMNBrdU was corrected for the disappearance (half-life) of cells in the circulation. In a previous study, Bicknell et al. (5), using a whole blood transfusion method, reported that the half-life of PMNBrdU in rabbits was 270 min or 4.5 h. We have applied this rate of exponential loss of PMNBrdU from the circulation to calculate the number of PMNBrdU released from the bone marrow and the transit time through the different pools (27).

Statistical analysis. All values are expressed as means ± SE. Differences in TNF-alpha values and PMN transit times were evaluated with a one-way ANOVA. In vivo data were analyzed with a two-way ANOVA for repeated measures, and Bonferroni's correction was done for multiple comparisons. A value of P < 0.05 was accepted as significant.


    RESULTS
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

Composition of particles. Table 1 summarizes the elemental composition of the EHC-93 particles as total content and soluble content as adapted from Vincent et al. (35). The calculated dose of soluble elements instilled into the lungs of rabbits is comparable to that in rats exposed for 4 h to 5 mg/m3 of EHC-93 and is considered environmentally relevant (34). This dose does not cause histological changes indicative of injury in the lung. Similarly, qualitative evaluation of lung tissue sections in our study showed no signs of inflammation in regions of supernatant instillation compared with contralateral control regions of the lung (Fig. 1B).

                              
View this table:
[in this window]
[in a new window]
  		Table 1.   Chemistry of EHC-93 soluble fraction and soluble fraction instilled in rabbits



View larger version (66K):
[in this window]
[in a new window]
  		Fig. 1.   A: photomicrograph of human alveolar macrophages (AMs) stained with Wright's solution after incubation for 24 h with the urban air particles (EHC-93) in vitro. The majority of AMs ingested 1 or more particles (arrow). Bar, 10 µm. B: region of lung tissue where the supernatants were instilled. There were no inflammatory changes in either the smaller bronchioles, alveolar walls, or air spaces. Bar, 20 µm.

TNF-alpha produced by human AMs stimulated with PM10. When human AMs were incubated with 0.1 mg/ml of PM10 for 24 h, they phagocytosed the particles (Fig. 1A). Incubation with different concentrations of PM10 resulted in a dose-dependent increase in TNF-alpha secretion by human AMs (Fig. 2), and the 0.1 mg/ml concentration of PM10 resulted in a response similar to that produced by 1 µg/ml of lipopolysaccharide (Sigma).


View larger version (15K):
[in this window]
[in a new window]
  		Fig. 2.   Tumor necrosis factor (TNF)-alpha production by human AMs exposed to urban air particles and lipopolysaccharide (LPS; 1 µg/ml). PM10, particulate matter < 10 µm. Data are means ± SE of 5 (urban air particles) and 3 (LPS) experiments performed with AMs from different donors. The urban air particles caused a dose-dependent increase in TNF-alpha production, and the results with highest dose of particles were similar to those with LPS.* P < 0.05 vs. medium.

Supernatants from AMs and the release of PMNs from the bone marrow. Instillation of the supernatants from human AMs (6 h; P < 0.05) and rabbit AMs (6 h; P < 0.05) incubated with PM10 caused a similar temporary increase in circulating PMNs (Fig. 3A). Circulating band cell counts also increased after instillation of the supernatants in the human AM plus PM10 group at 6 and 9 h and in the rabbit AM plus PM10 group at 6 h (Fig. 3B). There was no significant difference in the PMN and band cell counts between the human AM plus PM10 and rabbit AM plus PM10 groups.


View larger version (18K):
[in this window]
[in a new window]
  		Fig. 3.   Circulating polymorphonuclear leukocyte (PMN; A) and band cell (B) counts after instillation of supernatants from cultured rabbit (n = 4) and human (n = 6) AMs with PM10 and from human AMs cultured without PM10 (n = 5). 5-Bromo-2'-deoxyuridine (BrdU) was used to label the cells. Values are means ± SE. Note the increase in PMNs and band cells induced by supernatants from human and rabbit AMs 6 h after instillation. Band cells were also significantly increased 9 h after instillation of supernatants from human AMs stimulated with PM10. * P < 0.05 compared with human AMs cultured without PM10.

Figure 4 shows the percentage (A) and number (B) of PMNBrdU in the circulation over time. Supernatants from both human and rabbit AMs stimulated with PM10 shifted these curves to the left (Fig. 4). Figure 5 shows the G3 cells that represent the transit of PMNs through the postmitotic pool, and Fig. 6 shows the G1 cells that represent the transit of PMNs through the mitotic plus postmitotic pools. Both G3 (Fig. 5) and G1 (Fig. 6) cells show that the supernatants from rabbit and human AMs stimulated with PM10 causes a left shift of the curve compared with that from control human AMs.


View larger version (19K):
[in this window]
[in a new window]
  		Fig. 4.   Percentage (A) and number (B) of all BrdU-labeled PMNs in the circulation after instillation of supernatant from AMs cultured with and without PM10. Values are means ± SE. Note the early peaks at 36 h and rapid decline in circulating BrdU-labeled PMNs after instillation of supernatants from the human (n = 6) AM plus PM10 and rabbit (n = 5) AM plus PM10 groups compared with those from the human (n = 4) AM group. * P < 0.05 compared with human AMs cultured without PM10.



View larger version (16K):
[in this window]
[in a new window]
  		Fig. 5.   Percentage (A) and number (B) of G3 cells (see text for description) in the circulation after instillation of supernatants from AMs cultured with and without PM10. Values are means ± SE. Note the early peaks at 36 h in the human (n = 6) AM plus PM10 and rabbit (n = 5) AM plus PM10 groups compared with those in the human (n = 4) AM group.



View larger version (18K):
[in this window]
[in a new window]
  		Fig. 6.   Percentage (A) and number (B) of G1 cells (see text for description) in the circulation after instillation of supernatants from AMs cultured with and without PM10. Values are means ± SE. Note the lower values at 144 h in the human (n = 6) AM plus PM10 and rabbit (n = 5) AM plus PM10 groups compared with those in the human (n = 4) AM group. * P < 0.05 compared with the human AMs cultured without PM10.

Table 2 shows the calculated transit time of all the different populations of PMNBrdU (all PMNBrdU and G3, G2, and G1 cells). The data show that compared with the effect of the instillation of supernatants from human AMs incubated without particles, supernatants from human (P < 0.01) and rabbit (P < 0.05) AMs incubated with PM10 shortened the transit time of PMNs through the bone marrow. The transit time of PMNs through the postmitotic (G3; P < 0.01) and mitotic plus postmitotic (G1; P < 0.05) pools were shorter in human AMs incubated with than without PM10. There was no difference in PMN transit times between the instillation of supernatants from human and rabbit AMs stimulated with PM10 (Table 2) and supernatants incubated only in RPMI 1640 medium (29).

                              
View this table:
[in this window]
[in a new window]
  		Table 2.   Transit times of PMNs through the bone marrow

Urban air particles contain small amounts of endotoxin (4, 34, 35), and the PM10 (0.1 mg/ml) dose used in this study contained trace amounts of endotoxin (0.096 endotoxin unit/ml). Instillation of RPMI 1640 medium containing the same amount of endotoxin present in 0.1 mg/ml of PM10 into rabbit lungs (n = 4) produced transit times of PMNs through the bone marrow that were similar to those of human AMs alone (all PMNs, 105.5 ± 4.1 vs. 104.9 ± 2.4 h; G3 cells, 65.5 ± 3.3 vs. 65.7 ± 2.7 h; G2 cells, 90.0 ± 3.5 vs. 92.3 ± 2.3 h; G1 cells, 136.6 ± 5.4 vs. 130.7 ± 3.4 h).


    DISCUSSION
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

The results of this study show that when human AMs phagocytose atmospheric PM10, they secrete mediators such as TNF-alpha in a dose-dependent manner. They also show that when supernatants from human AMs incubated with PM10 are instilled into the lungs of rabbits, the transit time of PMNs through both the mitotic and postmitotic bone marrow pools are shortened. Together these results show that mediators released from AMs after phagocytosis of atmospheric particles are important in eliciting the systemic response associated with particulate air pollution.

The biological mechanisms responsible for the adverse health effects of breathing particulate air pollution are not clear. Seaton et al. (25) proposed the hypothesis that the inhalation of fine particles provokes a low-grade inflammatory response in the lung that causes an exacerbation of lung disease and a change in blood coagulability that results in increased pulmonary and cardiovascular deaths. Because AMs are important in processing airborne particles, we postulate that they are critical in secreting the mediators that initiate a systemic response that includes the release of leukocytes from the bone marrow. The present study shows that human AMs exposed to PM10 collected in an urban environment are stimulated to secrete mediators such as TNF-alpha (Fig. 1) and that the mediators secreted by these human AMs and instilled into the lung of the rabbit stimulate the bone marrow (Table 2). This suggests that AMs are an important source of inflammatory mediators responsible for the systemic response after PM10 exposure.

We used TNF-alpha as a marker of AM stimulation by PM10, and the increased secretion of TNF-alpha is consistent with a previous report (4) with different urban air pollutants. AMs are also capable of producing numerous other mediators such as hematopoietic growth factors (granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor), IL-1, IL-6, and IL-8 (14, 18), all capable of stimulating the bone marrow. These mediators could spill over into the circulation and stimulate the bone marrow directly or indirectly via their effect on other effector cells in the lung or other organs. Other effector cells in the lung such as airway epithelial cells also produce inflammatory mediators when exposed to PM10 (21), but their role in this systemic inflammatory response is not well established. IL-1 and IL-6 play a critical role in the systemic inflammatory response by initiating the production of acute-phase proteins such as C-reactive protein, fibrinogen, complement, and antiproteases by the liver (10). Therefore, secondary mediator secretion by effector cells in the lung or distant organs such as the liver could also contribute to the observed bone marrow response.

The urban PM10 used in this study is a complex aggregate of elemental and organic carbons, metals, sulfates, nitrates, and organic contaminants (35). The metal components in these particles are thought to contribute to their ability to cause oxidant stress and cytokine production in AMs (11). Becker et al. (4) have suggested that endotoxin contributes to cytokine production by AMs because the cytokine response to PM10 was partly inhibitable by polymyxin B (4). Trace amounts of endotoxin were detected on the EHC-93 particles used in this study, but instillation of a similar amount of endotoxin into the lungs of rabbits did not alter the PMN transit time through the bone marrow. This suggests that the endotoxin contamination cannot explain the bone marrow stimulation induced by EHC-93 particles. Other soluble components of EHC-93 particles have been shown to induce an acute inflammatory response in the lungs of mice (2), although the dose used was 500 times higher than the calculated dose we used in our study (Table 1). Therefore, the small dose of particles we used in our experiments makes it unlikely that the soluble elements of the EHC-93 in the supernatants contribute to the bone marrow stimulation we observed. Furthermore, the dose of PM10 we used is not cytotoxic to AMs when structural integrity end points are measured (16), indicating that proteases and esterases released from damaged AMs are responsible for bone marrow stimulation. Further studies are needed to determine which component(s) of PM10 is responsible for cytokine production by AMs and which mediator or mediators cause the bone marrow release of PMNs.

A major question that we addressed in this study is whether the rabbit model we used to study bone marrow stimulation is suitable to study the effect of mediators produced by human AMs. The results show that the supernatants from AMs incubated with PM10 caused a shortening of these transit times and that this effect was similar when either human or rabbit AMs were incubated with the same amount of particles (Table 2). This suggests a large degree of interspecies homology between the cytokines of humans and rabbits (22, 32), allowing the rabbit to be used to study the effects of mediator release from human AMs. This model provides an advantage because the thymidine analog BrdU used to measure the transit time of PMNs through the mitotic and postmitotic bone marrow pools (17, 27-31) cannot be used in humans. It also allows us to study the functional characteristics and intravascular behavior of the newly released cells. The AMs used in this study were obtained from smokers who are urban dwellers, both factors that could potentially influence the response of these cells to particles. Although AMs from young healthy nonsmoking volunteers would minimize variables such as the effect of chronic smoking on the AM response, the subjects in our study represented the target population vulnerable to the adverse health effects of exposure to particle air pollution (6, 7, 19, 20).

This study shows a shortening of the transit time of PMNs through the bone marrow and an increased number of band cells in the circulation induced by PM10, indicating that the number of circulating immature PMNs has increased. Lichtman and Weed (15) showed that immature PMNs harvested from the bone marrow are larger and less deformable than their circulating counterparts. Our laboratory has shown that immature PMNs newly released from the bone marrow by acute pneumonia (23) and cigarette smoke exposure (31) preferentially sequester in the pulmonary microvessels. These immature PMNs were also slow to migrate out of the capillaries into an inflammatory site (23), and it is reasonable to postulate that activation of these sequestered PMNs in lung microvessels could cause endothelial damage. We speculate that the increased burden of immature PMNs in the lung could contribute to the observed decrease in lung function associated with chronic exposure to particulate air pollutants. Furthermore, cytokines such as IL-6 stimulate the bone marrow to produce platelets and the liver to produce coagulation factors (10, 25), and these prothrombotic factors could contribute to the cardiovascular events associated with exposure to particulate air pollution.

In summary, our results show that mediators released from AMs after phagocytosis of ambient particulate matter collected in a major North American city induces a systemic inflammatory response that includes stimulation of the bone marrow. This bone marrow stimulation results in the release of immature PMNs into the circulation, and we speculate that both these leukocytes and the circulating inflammatory mediators released from AMs play an important role in the pathogenesis of the pulmonary and cardiovascular diseases associated with particulate air pollution.


    ACKNOWLEDGEMENTS

We thank Jennifer Hards and Mark Elliott for technical support and Health Canada (Ottawa, ON) for making the EHC-93 available.


    FOOTNOTES

The work was supported by Medical Research Council of Canada Grant 4219 and the British Columbia Lung Association.

Address for reprint requests and other correspondence: S. F. van Eeden, Pulmonary Research Laboratory, Univ. of British Columbia, St. Paul's Hospital, 1081 Burrard St., Vancouver, BC, Canada V6Z 1Y6 (E-mail: svaneeden{at}mrl.ubc.ca).

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Received 30 November 1999; accepted in final form 9 June 2000.


    REFERENCES
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

1.   Abbey, DE, Burchette RJ, Knutsen SF, McDonnell WF, Lebowitz MD, and Enright PL. Long-term particulate and other air pollutants and lung function in nonsmokers. Am J Respir Crit Care Med 158: 289-298, 1998[Abstract/Free Full Text].

2.   Adamson, IY, Prieditis H, and Vincent R. Pulmonary toxicity of an atmospheric particulate sample is due to the soluble fraction. Toxicol Appl Pharmacol 157: 43-50, 1999[Web of Science][Medline].

3.   Becker, S, and Soukup JM. Exposure to urban air particulates alters the macrophage mediated inflammatory response to respiratory viral infection. J Toxicol Environ Health 57: 445-457, 1999.

4.   Becker, S, Soukup JM, Gilmour MI, and Devlin RB. Stimulation of human and rat alveolar macrophages by urban air particles: effects on oxidant radical generation and cytokine production. Toxicol Appl Pharmacol 141: 637-648, 1996[Web of Science][Medline].

5.   Bicknell, S, van Eeden SF, Hayashi S, Hards J, English D, and Hogg JC. A non-radioisotopic method for tracing neutrophils in vivo using 5'-bromo-2'-deoxyuridine. Am J Respir Cell Mol Biol 10: 16-23, 1994[Abstract].

6.   Committee of the Environmental and Occupational Health Assembly of the American Thoracic Society. Health effects of outdoor air pollution. Am J Respir Crit Care Med 153: 3-50, 1996[Abstract].

7.   Dockery, DW, Pope CA, Xu X, III, Spengler JD, Ware JH, Fay ME, Ferris BG, Jr, and Speizer FE. An association between air pollution and mortality in six U. S. cities. N Engl J Med 329: 1753-1759, 1993[Abstract/Free Full Text].

8.   Friedman, GD, Klatsky AL, and Siegelaub AB. The leukocyte count as a predictor of myocardial infarction. N Engl J Med 290: 1275-1278, 1974.

9.   Furman, MI, Becker RC, Yarzebski J, Savegeau J, Gore JM, and Goldberg RJ. Effect of elevated leukocyte count on in-hospital mortality following acute myocardial infarction. Am J Cardiol 78: 945-948, 1996[Web of Science][Medline].

10.   Gabay, C, and Kushner I. Acute-phase proteins and other systemic responses to inflammation. N Engl J Med 340: 448-454, 1999[Free Full Text].

11.   Goldsmith, CAW, Imrich A, Danaee H, Ning YY, and Kobzik L. Analysis of air pollution particulate-mediated oxidant stress in alveolar macrophages. J Toxicol Environ Health 54: 529-545, 1998.

12.   Grimm, RH, Jr, Neaton JD, and Ludwig W. Prognostic importance of the white blood cell count for coronary, cancer, and all-cause mortality. JAMA 254: 1932-1937, 1985[Abstract/Free Full Text].

13.   Hubl, W, Andert S, Thum G, Ortner S, and Bayer PM. Value of neutrophil CD16 expression for detection of left shift and acute-phase response. Am J Clin Pathol 107: 187-196, 1997[Web of Science][Medline].

14.   Lee, M, Segal GM, and Bagby GC. Interleukin-1 induces human bone marrow-derived fibroblasts to produce multilineage hematopoietic growth factors. Exp Hematol 15: 983-988, 1987[Web of Science][Medline].

15.   Lichtman, MA, and Weed RI. Alteration of the cell periphery during granulocyte maturation: relationship to cell function. Blood 39: 301-316, 1972[Abstract/Free Full Text].

16.   Nadeau, D, Vincent R, Kumarathasan P, Brook J, and Dufresne S. Cytotoxicity of ambient air particles to rat lung macrophages: comparison of cellular and functional assays. Toxicol In Vitro 10: 161-172, 1996.

17.   Nakagawa, M, Terashima T, D'yachkova Y, Bondy GP, Hogg JC, and van Eeden SF. Glucocorticoid-induced granulocytosis: contribution of marrow release and demargination of intravascular granulocytes. Circulation 98: 2307-2313, 1998[Abstract/Free Full Text].

18.   Platzer, E. Human hemopoietic growth factors. Eur J Haematol 42: 1-15, 1989[Web of Science][Medline].

19.   Pope, CA, III, Dockery DW, Spengler JD, and Raizenne ME. Respiratory health and PM10 pollution. A daily time series analysis. Am Rev Respir Dis 144: 668-674, 1991[Web of Science][Medline].

20.   Pope, CA, III, Thun MJ, Namboodiri MM, Dockery DW, Evans JS, Speizer FE, and Heath CW, Jr. Particulate air pollution as a predictor of mortality in a prospective study of U. S. adults. Am J Respir Crit Care Med 151: 669-674, 1995[Abstract].

21.   Quay, JL, Reed W, Samet J, and Devlin RB. Air pollution particles induce IL-6 gene expression in human airway epithelial cells via NF-kappa B activation. Am J Respir Cell Mol Biol 19: 98-106, 1998[Abstract/Free Full Text].

22.   Sakata, Y, Morimoto A, Long NC, and Murakami N. Fever and acute-phase response induced in rabbits by intravenous and intra-cerebroventricular injection of interleukin-6. Cytokines 3: 199-203, 1991.

23.   Sato, Y, van Eeden SF, English D, and Hogg JC. Bacteremic pneumococcal pneumonia: bone marrow release and pulmonary sequestration of neutrophils. Crit Care Med 26: 501-509, 1998[Web of Science][Medline].

24.   Schwartz, J, and Dockery DW. Increased mortality in Philadelphia associated with daily air pollution concentrations. Am Rev Respir Dis 145: 600-604, 1992[Web of Science][Medline].

25.   Seaton, A, MacNee W, Donaldson K, and Godden D. Particulate air pollution and acute health effects. Lancet 345: 176-178, 1995[Web of Science][Medline].

26.   Tan, WC, van Eeden SF, Qiu DW, Liam BL, D'yachkova Y, and Hogg JC. Particulate air pollution, bone marrow stimulation and the pathogenesis of excess cardiovascular and pulmonary deaths (Abstract). Eur Respir J 12: 259S, 1998.

27.   Terashima, T, Wiggs B, English D, Hogg JC, and van Eeden SF. Polymorphonuclear leukocyte transit times in bone marrow during streptococcal pneumonia. Am J Physiol Lung Cell Mol Physiol 271: L587-L592, 1996[Abstract/Free Full Text].

28.   Terashima, T, Wiggs B, English D, Hogg JC, and van Eeden SF. The effect of cigarette smoking on the bone marrow. Am J Respir Crit Care Med 155: 1021-1026, 1997[Abstract].

29.   Terashima, T, Wiggs B, English D, Hogg JC, and van Eeden SF. Phagocytosis of small carbon particles (PM10) by alveolar macrophages stimulates the release of polymorphonuclear leukocytes from bone marrow. Am J Respir Crit Care Med 155: 1441-1447, 1997[Abstract].

30.   Terashima, T, English D, Hogg JC, and van Eeden SF. Release of polymorphonuclear leukocytes from the bone marrow by interleukin-8. Blood 92: 1062-1069, 1998[Abstract/Free Full Text].

31.   Terashima, T, Klut ME, English D, Hards J, Hogg JC, and van Eeden SF. Cigarette smoking causes sequestration of polymorphonuclear leukocytes released from the bone marrow in lung microvessels. Am J Respir Cell Mol Biol 20: 171-177, 1999[Abstract/Free Full Text].

32.   Ulich, TR, del Castillo J, Keys M, Granger GA, and Ni RX. Kinetics and mechanisms of recombinant human interleukin 1 and tumor necrosis factor-alpha -induced changes in circulating numbers of neutrophils and lymphocytes. J Immunol 139: 3406-3415, 1987[Abstract].

33.   Utell, MJ, and Samet JM. Particulate air pollution and health: new evidence on an old problem. Am Rev Respir Dis 147: 1334-1335, 1993[Web of Science][Medline].

34.   Vincent, R, Bjarnason SG, Adamson IY, Hedgecock C, Kumarathasan P, Guenette J, Potvin M, Goegan P, and Bouthillier L. Acute pulmonary toxicity of urban particulate matter and ozone. Am J Pathol 151: 1563-1570, 1997[Abstract].

35.   Vincent, R, Goegan P, Johnson G, Brook JR, Kumarathasan P, Bouthillier L, and Burnett RT. Regulation of promoter-CAT stress genes in HepG2 cells by suspensions of particles from ambient air. Fundam Appl Toxicol 39: 18-32, 1997[Web of Science][Medline].

36.   Weiss, ST, Segal MR, Sparrow D, and Wager C. Relation of FEV1 and peripheral blood leukocyte count to total mortality: the normative aging study. Am J Epidemiol 142: 493-498, 1995[Abstract/Free Full Text].

Am J Physiol Lung Cell Mol Physiol 279(5):L924-L931
1040-0605/00 $5.00 Copyright © 2000 the American Physiological Society


This article has been cited by other articles:


Home page
 Eur Respir JHome page
J. R. Swiston, W. Davidson, S. Attridge, G. T. Li, M. Brauer, and S. F. van Eeden
Wood smoke exposure induces a pulmonary and systemic inflammatory response in firefighters
Eur. Respir. J., July 1, 2008; 32(1): 129 - 138.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
K. Yatera, J. Hsieh, J. C. Hogg, E. Tranfield, H. Suzuki, C.-H. Shih, A. R. Behzad, R. Vincent, and S. F. van Eeden
Particulate matter air pollution exposure promotes recruitment of monocytes into atherosclerotic plaques
Am J Physiol Heart Circ Physiol, February 1, 2008; 294(2): H944 - H953.
[Abstract] [Full Text] [PDF]

Home page
 Eur Respir JHome page
D. M. Mannino, G. Watt, D. Hole, C. Gillis, C. Hart, A. McConnachie, G. Davey Smith, M. Upton, V. Hawthorne, D. D. Sin, et al.
The natural history of chronic obstructive pulmonary disease.
Eur. Respir. J., March 1, 2006; 27(3): 627 - 643.
[Full Text] [PDF]

Home page
 Proc Am Thorac SocHome page
S. F. P. Man and D. D. Sin
Effects of Corticosteroids on Systemic Inflammation in Chronic Obstructive Pulmonary Disease
Proceedings of the ATS, April 1, 2005; 2(1): 78 - 82.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
M. Sakai, Y. Sato, S. Sato, S. Ihara, M. Onizuka, Y. Sakakibara, and H. Takahashi
Effect of relocating to areas of reduced atmospheric particulate matter levels on the human circulating leukocyte count
J Appl Physiol, November 1, 2004; 97(5): 1774 - 1780.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Respir. Crit. Care Med.Home page
Y. Goto, H. Ishii, J. C. Hogg, C.-H. Shih, K. Yatera, R. Vincent, and S. F. van Eeden
Particulate Matter Air Pollution Stimulates Monocyte Release from the Bone Marrow
Am. J. Respir. Crit. Care Med., October 15, 2004; 170(8): 891 - 897.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Lung Cell. Mol. Physiol.Home page
Y. Goto, J. C. Hogg, C.-H. Shih, H. Ishii, R. Vincent, and S. F. van Eeden
Exposure to ambient particles accelerates monocyte release from bone marrow in atherosclerotic rabbits
Am J Physiol Lung Cell Mol Physiol, July 1, 2004; 287(1): L79 - L85.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Lung Cell. Mol. Physiol.Home page
H. Ishii, T. Fujii, J. C. Hogg, S. Hayashi, H. Mukae, R. Vincent, and S. F. van Eeden
Contribution of IL-1{beta} and TNF-{alpha} to the initiation of the peripheral lung response to atmospheric particulates (PM10)
Am J Physiol Lung Cell Mol Physiol, July 1, 2004; 287(1): L176 - L183.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Cell Physiol.Home page
Y. Goto, J. C. Hogg, T. Suwa, K. B. Quinlan, and S. F. van Eeden
A novel method to quantify the turnover and release of monocytes from the bone marrow using the thymidine analog 5'-bromo-2'-deoxyuridine
Am J Physiol Cell Physiol, August 1, 2003; 285(2): C253 - C259.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Lung Cell. Mol. Physiol.Home page
T. Fujii, J. C. Hogg, N. Keicho, R. Vincent, S. F. Van Eeden, and S. Hayashi
Adenoviral E1A modulates inflammatory mediator expression by lung epithelial cells exposed to PM10
Am J Physiol Lung Cell Mol Physiol, February 1, 2003; 284(2): L290 - L297.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Respir. Cell Mol. Bio.Home page
T. Fujii, S. Hayashi, J. C. Hogg, H. Mukae, T. Suwa, Y. Goto, R. Vincent, and S. F. van Eeden
Interaction of Alveolar Macrophages and Airway Epithelial Cells Following Exposure to Particulate Matter Produces Mediators that Stimulate the Bone Marrow
Am. J. Respir. Cell Mol. Biol., July 1, 2002; 27(1): 34 - 41.
[Abstract] [Full Text] [PDF]

Home page
 J Am Coll CardiolHome page
T. Suwa, J. C. Hogg, K. B. Quinlan, A. Ohgami, R. Vincent, and S. F. van Eeden
Particulate air pollution induces progression of atherosclerosis
J. Am. Coll. Cardiol., March 20, 2002; 39(6): 935 - 942.
[Abstract] [Full Text] [PDF]

Home page
 ChestHome page
J.-i. Ashitani, H. Mukae, T. Hiratsuka, M. Nakazato, K. Kumamoto, and S. Matsukura
Elevated Levels of {alpha}-Defensins in Plasma and BAL Fluid of Patients With Active Pulmonary Tuberculosis
Chest, February 1, 2002; 121(2): 519 - 526.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Respir. Cell Mol. Bio.Home page
T. Fujii, S. Hayashi, J. C. Hogg, R. Vincent, and S. F. Van Eeden
Particulate Matter Induces Cytokine Expression in Human Bronchial Epithelial Cells
Am. J. Respir. Cell Mol. Biol., September 1, 2001; 25(3): 265 - 271.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (28)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mukae, H.
Right arrow Articles by van Eeden, S. F.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mukae, H.
Right arrow Articles by van Eeden, S. F.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online