Limits...
Lung exposure of titanium dioxide nanoparticles induces innate immune activation and long-lasting lymphocyte response in the Dark Agouti rat.

Gustafsson Å, Lindstedt E, Elfsmark LS, Bucht A - J Immunotoxicol (2011)

Bottom Line: Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects.Lymphocytes recruited to the lungs were predominantly CD4(+) helper T-cells, but we also demonstrated presence of CD8(+) T-cells, B-cells, and CD25(+) T-cells.In serum, we detected both an early cytokine expression at Days 1-2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-γ] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-α), indicating systemic late-phase effects in addition to the local response in airways.

View Article: PubMed Central - PubMed

Affiliation: Division of CBRN Defense and Security, Swedish Defense Research Agency, Umeå, Sweden. asa.gustafsson@foi.se

ABSTRACT
Nanomaterial of titanium dioxide (TiO(2)) is manufactured in large-scale production plants, resulting in risks for accidental high exposures of humans. Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects. By using the Dark Agouti (DA) rat, a strain disposed to develop chronic inflammation following exposure to immunoactivating adjuvants, we investigated local and systemic inflammatory responses after lung exposure of nanosized TiO(2) particles up to 90 days after intratracheal instillation. TiO(2) induced a transient response of proinflammatory and T-cell-activating cytokines (interleukin [IL]-1α, IL-1β, IL-6, cytokine-induced neutrophil chemoattractant [CINC]-1, granulocyte-macrophage colony-stimulating factor [GM-CSF], and IL-2) in airways 1-2 days after exposure, accompanied by an influx of eosinophils and neutrophils. Neutrophil numbers remained elevated for 30 days, whereas the eosinophils declined to baseline levels at Day 8, simultaneously with an increase of dendritic cells and natural killer (NK) cells. The innate immune activation was followed by a lymphocyte expansion that persisted throughout the 90-day study. Lymphocytes recruited to the lungs were predominantly CD4(+) helper T-cells, but we also demonstrated presence of CD8(+) T-cells, B-cells, and CD25(+) T-cells. In serum, we detected both an early cytokine expression at Days 1-2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-γ] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-α), indicating systemic late-phase effects in addition to the local response in airways. In summary, these data demonstrate a dynamic response to TiO(2) nanoparticles in the lungs of DA rats, beginning with an innate immune activation of eosinophils, neutrophils, dendritic cells, and NK cells, followed by a long-lasting activation of lymphocytes involved in adaptive immunity. The results have implications for the assessment of risks for adverse and persistent immune stimulation following nanoparticle exposures in sensitive populations.

Show MeSH

Related in: MedlinePlus

Numbers of cytotoxic T-cells (CD3+ CD8+) and CD4+ T-cells, and median intensity of CD25 receptor expression on CD4+ T-cells in bronchoalveolar lavage fluid from nanosized TiO2 (5 mg/kg) exposed rats 0 (n = 5), 1 (n = 7), 2 (n = 7), 8 (n = 10), 16 (n = 5), 30 (n = 5), and 90 (n = 4) days after a single intratracheal instillation. Kruskal–Wallis test with Dunn's post-test; value is significantly (*P < 0.05, **P < 0.01, ***P < 0.001) different vs. control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC3104284&req=5

fig4: Numbers of cytotoxic T-cells (CD3+ CD8+) and CD4+ T-cells, and median intensity of CD25 receptor expression on CD4+ T-cells in bronchoalveolar lavage fluid from nanosized TiO2 (5 mg/kg) exposed rats 0 (n = 5), 1 (n = 7), 2 (n = 7), 8 (n = 10), 16 (n = 5), 30 (n = 5), and 90 (n = 4) days after a single intratracheal instillation. Kruskal–Wallis test with Dunn's post-test; value is significantly (*P < 0.05, **P < 0.01, ***P < 0.001) different vs. control.

Mentions: One single instillation of 5mg nano-TiO2 NPs/kg induced early eosinophil and neutrophil recruitment to the airways appearing from Day 1 post-exposure when comparedwith unexposed animals (Figure 2). The eosinophils were elevated until Day 8, whereas the neutrophils remained elevated for at least 30 days. Concomitant with the neutrophilia, a transient increase of dendritic cells was detected with a peak cell numbers at Day 8 (Figure 3), followed by maximal lymphocyte cell numbers at Day 16, which persisted throughout the 90-day study (Figure 2). The nano-TiO2-exposed animals were also compared with animals exposed for PBS only. The numbers of neutrophils, lymphocytes, and eosinophils were not increased following PBS instillation (Figure 2) compared with baseline cell numbers in BALF of healthy animals, although a small increase of macrophages was observed at Day 90. Among the lymphocytes, NK cells and T-cells expressing the NKR-P1A receptor (NK T-cells) displayed a transient increase at the same timepoints as dendritic cells (Figure 3). NK cells recruited to the airways expressed high density of the NKR-P1A receptor on the cell surface as indicated by the increased NKR-P1Abright population at Days 2, 8, and 16 (Table 1). The lymphocyte response was dominated by T-cells, including CD4+ helper T-cells with high expression of CD25 (CD25bright) (Figure 4). Smaller fractions of lymphocytes were identified as CD8+ cytotoxic T-cells and B-cells (Figures 3 and 4). T-Cells recruited to the airways were predominantly of the T-cell receptor (TCR) αβ subset with a minor proportion of T-cells expressing the γδ TCR (data not shown).


Lung exposure of titanium dioxide nanoparticles induces innate immune activation and long-lasting lymphocyte response in the Dark Agouti rat.

Gustafsson Å, Lindstedt E, Elfsmark LS, Bucht A - J Immunotoxicol (2011)

Numbers of cytotoxic T-cells (CD3+ CD8+) and CD4+ T-cells, and median intensity of CD25 receptor expression on CD4+ T-cells in bronchoalveolar lavage fluid from nanosized TiO2 (5 mg/kg) exposed rats 0 (n = 5), 1 (n = 7), 2 (n = 7), 8 (n = 10), 16 (n = 5), 30 (n = 5), and 90 (n = 4) days after a single intratracheal instillation. Kruskal–Wallis test with Dunn's post-test; value is significantly (*P < 0.05, **P < 0.01, ***P < 0.001) different vs. control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3104284&req=5

fig4: Numbers of cytotoxic T-cells (CD3+ CD8+) and CD4+ T-cells, and median intensity of CD25 receptor expression on CD4+ T-cells in bronchoalveolar lavage fluid from nanosized TiO2 (5 mg/kg) exposed rats 0 (n = 5), 1 (n = 7), 2 (n = 7), 8 (n = 10), 16 (n = 5), 30 (n = 5), and 90 (n = 4) days after a single intratracheal instillation. Kruskal–Wallis test with Dunn's post-test; value is significantly (*P < 0.05, **P < 0.01, ***P < 0.001) different vs. control.
Mentions: One single instillation of 5mg nano-TiO2 NPs/kg induced early eosinophil and neutrophil recruitment to the airways appearing from Day 1 post-exposure when comparedwith unexposed animals (Figure 2). The eosinophils were elevated until Day 8, whereas the neutrophils remained elevated for at least 30 days. Concomitant with the neutrophilia, a transient increase of dendritic cells was detected with a peak cell numbers at Day 8 (Figure 3), followed by maximal lymphocyte cell numbers at Day 16, which persisted throughout the 90-day study (Figure 2). The nano-TiO2-exposed animals were also compared with animals exposed for PBS only. The numbers of neutrophils, lymphocytes, and eosinophils were not increased following PBS instillation (Figure 2) compared with baseline cell numbers in BALF of healthy animals, although a small increase of macrophages was observed at Day 90. Among the lymphocytes, NK cells and T-cells expressing the NKR-P1A receptor (NK T-cells) displayed a transient increase at the same timepoints as dendritic cells (Figure 3). NK cells recruited to the airways expressed high density of the NKR-P1A receptor on the cell surface as indicated by the increased NKR-P1Abright population at Days 2, 8, and 16 (Table 1). The lymphocyte response was dominated by T-cells, including CD4+ helper T-cells with high expression of CD25 (CD25bright) (Figure 4). Smaller fractions of lymphocytes were identified as CD8+ cytotoxic T-cells and B-cells (Figures 3 and 4). T-Cells recruited to the airways were predominantly of the T-cell receptor (TCR) αβ subset with a minor proportion of T-cells expressing the γδ TCR (data not shown).

Bottom Line: Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects.Lymphocytes recruited to the lungs were predominantly CD4(+) helper T-cells, but we also demonstrated presence of CD8(+) T-cells, B-cells, and CD25(+) T-cells.In serum, we detected both an early cytokine expression at Days 1-2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-γ] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-α), indicating systemic late-phase effects in addition to the local response in airways.

View Article: PubMed Central - PubMed

Affiliation: Division of CBRN Defense and Security, Swedish Defense Research Agency, Umeå, Sweden. asa.gustafsson@foi.se

ABSTRACT
Nanomaterial of titanium dioxide (TiO(2)) is manufactured in large-scale production plants, resulting in risks for accidental high exposures of humans. Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects. By using the Dark Agouti (DA) rat, a strain disposed to develop chronic inflammation following exposure to immunoactivating adjuvants, we investigated local and systemic inflammatory responses after lung exposure of nanosized TiO(2) particles up to 90 days after intratracheal instillation. TiO(2) induced a transient response of proinflammatory and T-cell-activating cytokines (interleukin [IL]-1α, IL-1β, IL-6, cytokine-induced neutrophil chemoattractant [CINC]-1, granulocyte-macrophage colony-stimulating factor [GM-CSF], and IL-2) in airways 1-2 days after exposure, accompanied by an influx of eosinophils and neutrophils. Neutrophil numbers remained elevated for 30 days, whereas the eosinophils declined to baseline levels at Day 8, simultaneously with an increase of dendritic cells and natural killer (NK) cells. The innate immune activation was followed by a lymphocyte expansion that persisted throughout the 90-day study. Lymphocytes recruited to the lungs were predominantly CD4(+) helper T-cells, but we also demonstrated presence of CD8(+) T-cells, B-cells, and CD25(+) T-cells. In serum, we detected both an early cytokine expression at Days 1-2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-γ] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-α), indicating systemic late-phase effects in addition to the local response in airways. In summary, these data demonstrate a dynamic response to TiO(2) nanoparticles in the lungs of DA rats, beginning with an innate immune activation of eosinophils, neutrophils, dendritic cells, and NK cells, followed by a long-lasting activation of lymphocytes involved in adaptive immunity. The results have implications for the assessment of risks for adverse and persistent immune stimulation following nanoparticle exposures in sensitive populations.

Show MeSH
Related in: MedlinePlus