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Inflammatory and cytotoxic responses of an alveolar-capillary coculture model to silica nanoparticles: comparison with conventional monocultures.

Kasper J, Hermanns MI, Bantz C, Maskos M, Stauber R, Pohl C, Unger RE, Kirkpatrick JC - Part Fibre Toxicol (2011)

Bottom Line: Attention should primarily be focussed on SNP effects on biological barriers.This may mimic the early inflammatory events that take place in the pulmonary alveoli after aSNP inhalation.Furthermore, a number of apoptosis markers belonging to the intrinsic pathway were upregulated in the coculture following aSNP treatment.

View Article: PubMed Central - HTML - PubMed

Affiliation: University Medical Centre, Institute of Pathology, Mainz, Germany.

ABSTRACT

Background: To date silica nanoparticles (SNPs) play an important role in modern technology and nanomedicine. SNPs are present in various materials (tyres, electrical and thermal insulation material, photovoltaic facilities). They are also used in products that are directly exposed to humans such as cosmetics or toothpaste. For that reason it is of great concern to evaluate the possible hazards of these engineered particles for human health. Attention should primarily be focussed on SNP effects on biological barriers. Accidentally released SNP could, for example, encounter the alveolar-capillary barrier by inhalation. In this study we examined the inflammatory and cytotoxic responses of monodisperse amorphous silica nanoparticles (aSNPs) of 30 nm in size on an in vitro coculture model mimicking the alveolar-capillary barrier and compared these to conventional monocultures.

Methods: Thus, the epithelial cell line, H441, and the endothelial cell line, ISO-HAS-1, were used in monoculture and in coculture on opposite sides of a filter membrane. Cytotoxicity was evaluated by the MTS assay, detection of membrane integrity (LDH release), and TER (Transepithelial Electrical Resistance) measurement. Additionally, parameters of inflammation (sICAM-1, IL-6 and IL-8 release) and apoptosis markers were investigated.

Results: Regarding toxic effects (viability, membrane integrity, TER) the coculture model was less sensitive to apical aSNP exposure than the conventional monocultures of the appropriate cells. On the other hand, the in vitro coculture model responded with the release of inflammatory markers in a much more sensitive fashion than the conventional monoculture. At concentrations that were 10-100fold less than the toxic concentrations the apically exposed coculture showed a release of IL-6 and IL-8 to the basolateral side. This may mimic the early inflammatory events that take place in the pulmonary alveoli after aSNP inhalation. Furthermore, a number of apoptosis markers belonging to the intrinsic pathway were upregulated in the coculture following aSNP treatment. Analysis of the individual markers indicated that the cells suffered from DNA damage, hypoxia and ER-stress.

Conclusion: We present evidence that our in vitro coculture model of the alveolar-capillary barrier is clearly advantageous compared to conventional monocultures in evaluating the extent of damage caused by hazardous material encountering the principle biological barrier in the lower respiratory tract.

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The release of inflammatory mediators was measured after aSNP (Ludox TM-40: light grey, NexSil20: dark grey) exposure of monocultures of H441 and ISO-HAS-1 on 96 well plates (conventional monoculture). After 4 h incubation, aSNPs were removed and the cells were cultivated for further 20 h to detect sICAM-1, IL-6 and IL-8 release. Data are depicted as means ± S.D. of one representative experiment out of three independent experiments with n = 3 samples for each treatment. All independent experiments showed a comparable reaction following aSNP treatment. *P < 0.05, ** P < 0.01 and *** P < 0.001 compared to the untreated control
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Figure 3: The release of inflammatory mediators was measured after aSNP (Ludox TM-40: light grey, NexSil20: dark grey) exposure of monocultures of H441 and ISO-HAS-1 on 96 well plates (conventional monoculture). After 4 h incubation, aSNPs were removed and the cells were cultivated for further 20 h to detect sICAM-1, IL-6 and IL-8 release. Data are depicted as means ± S.D. of one representative experiment out of three independent experiments with n = 3 samples for each treatment. All independent experiments showed a comparable reaction following aSNP treatment. *P < 0.05, ** P < 0.01 and *** P < 0.001 compared to the untreated control

Mentions: The release of inflammatory mediators measured after aSNP exposure of conventional monocultures on 96 well plates is shown in figure 3 for H441 and ISO-HAS-1 cells. For H441 cells even a concentration of 60 μg/ml NexSil20 induced a maximum release of sICAM-1 (Figure 3A). Concentrations of 300-600 μg/ml of both aSNPs show a 2fold increase of sICAM-1 for both cell lines compared to untreated controls (Figure 3A). Both aSNPs induced a maximum IL-6 release at concentrations of 60 μg/ml for H441 (Ludox TM-40: 1.4fold, NexSil20: 2fold) and 300 μg/ml for ISO-HAS-1 (2fold increase compared to untreated control) (Figure 3B). For both cell lines IL-8 release was seen at similar aSNP concentrations as for IL-6 (Figure 3C).


Inflammatory and cytotoxic responses of an alveolar-capillary coculture model to silica nanoparticles: comparison with conventional monocultures.

Kasper J, Hermanns MI, Bantz C, Maskos M, Stauber R, Pohl C, Unger RE, Kirkpatrick JC - Part Fibre Toxicol (2011)

The release of inflammatory mediators was measured after aSNP (Ludox TM-40: light grey, NexSil20: dark grey) exposure of monocultures of H441 and ISO-HAS-1 on 96 well plates (conventional monoculture). After 4 h incubation, aSNPs were removed and the cells were cultivated for further 20 h to detect sICAM-1, IL-6 and IL-8 release. Data are depicted as means ± S.D. of one representative experiment out of three independent experiments with n = 3 samples for each treatment. All independent experiments showed a comparable reaction following aSNP treatment. *P < 0.05, ** P < 0.01 and *** P < 0.001 compared to the untreated control
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3040689&req=5

Figure 3: The release of inflammatory mediators was measured after aSNP (Ludox TM-40: light grey, NexSil20: dark grey) exposure of monocultures of H441 and ISO-HAS-1 on 96 well plates (conventional monoculture). After 4 h incubation, aSNPs were removed and the cells were cultivated for further 20 h to detect sICAM-1, IL-6 and IL-8 release. Data are depicted as means ± S.D. of one representative experiment out of three independent experiments with n = 3 samples for each treatment. All independent experiments showed a comparable reaction following aSNP treatment. *P < 0.05, ** P < 0.01 and *** P < 0.001 compared to the untreated control
Mentions: The release of inflammatory mediators measured after aSNP exposure of conventional monocultures on 96 well plates is shown in figure 3 for H441 and ISO-HAS-1 cells. For H441 cells even a concentration of 60 μg/ml NexSil20 induced a maximum release of sICAM-1 (Figure 3A). Concentrations of 300-600 μg/ml of both aSNPs show a 2fold increase of sICAM-1 for both cell lines compared to untreated controls (Figure 3A). Both aSNPs induced a maximum IL-6 release at concentrations of 60 μg/ml for H441 (Ludox TM-40: 1.4fold, NexSil20: 2fold) and 300 μg/ml for ISO-HAS-1 (2fold increase compared to untreated control) (Figure 3B). For both cell lines IL-8 release was seen at similar aSNP concentrations as for IL-6 (Figure 3C).

Bottom Line: Attention should primarily be focussed on SNP effects on biological barriers.This may mimic the early inflammatory events that take place in the pulmonary alveoli after aSNP inhalation.Furthermore, a number of apoptosis markers belonging to the intrinsic pathway were upregulated in the coculture following aSNP treatment.

View Article: PubMed Central - HTML - PubMed

Affiliation: University Medical Centre, Institute of Pathology, Mainz, Germany.

ABSTRACT

Background: To date silica nanoparticles (SNPs) play an important role in modern technology and nanomedicine. SNPs are present in various materials (tyres, electrical and thermal insulation material, photovoltaic facilities). They are also used in products that are directly exposed to humans such as cosmetics or toothpaste. For that reason it is of great concern to evaluate the possible hazards of these engineered particles for human health. Attention should primarily be focussed on SNP effects on biological barriers. Accidentally released SNP could, for example, encounter the alveolar-capillary barrier by inhalation. In this study we examined the inflammatory and cytotoxic responses of monodisperse amorphous silica nanoparticles (aSNPs) of 30 nm in size on an in vitro coculture model mimicking the alveolar-capillary barrier and compared these to conventional monocultures.

Methods: Thus, the epithelial cell line, H441, and the endothelial cell line, ISO-HAS-1, were used in monoculture and in coculture on opposite sides of a filter membrane. Cytotoxicity was evaluated by the MTS assay, detection of membrane integrity (LDH release), and TER (Transepithelial Electrical Resistance) measurement. Additionally, parameters of inflammation (sICAM-1, IL-6 and IL-8 release) and apoptosis markers were investigated.

Results: Regarding toxic effects (viability, membrane integrity, TER) the coculture model was less sensitive to apical aSNP exposure than the conventional monocultures of the appropriate cells. On the other hand, the in vitro coculture model responded with the release of inflammatory markers in a much more sensitive fashion than the conventional monoculture. At concentrations that were 10-100fold less than the toxic concentrations the apically exposed coculture showed a release of IL-6 and IL-8 to the basolateral side. This may mimic the early inflammatory events that take place in the pulmonary alveoli after aSNP inhalation. Furthermore, a number of apoptosis markers belonging to the intrinsic pathway were upregulated in the coculture following aSNP treatment. Analysis of the individual markers indicated that the cells suffered from DNA damage, hypoxia and ER-stress.

Conclusion: We present evidence that our in vitro coculture model of the alveolar-capillary barrier is clearly advantageous compared to conventional monocultures in evaluating the extent of damage caused by hazardous material encountering the principle biological barrier in the lower respiratory tract.

Show MeSH
Related in: MedlinePlus