Evaluation of Dicarbonyls Generated in a Simulated Indoor Air Environment Using an In Vitro Exposure System

Abstract

Over the last two decades, there has been increasing awareness regarding the potential impact of indoor air pollution on health. Exposure to volatile organic compounds (VOCs) or oxygenated organic compounds formed from indoor chemistry has been suggested to contribute to adverse health effects. These studies use an in vitro monitoring system called VitroCell, to assess chemicals found in the indoor air environment. The structurally similar dicarbonyls diacetyl, 4-oxopentanal (4-OPA), glyoxal, glutaraldehyde, and methyl glyoxal were selected for use in this system. The VitroCell module was used to determine whether these dicarbonyls were capable of inducing inflammatory cytokine expression by exposed pulmonary epithelial cells (A549). Increases in the relative fold change in messenger RNA expression of the inflammatory mediators, interleukin (IL)-6, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor alpha (TNF-alpha) were identified following exposure to diacetyl, 4-OPA, glyoxal, glutaraldehyde, and methyl glyoxal when compared to a clean air control. Consistent results were observed when the protein levels of these cytokines were analyzed. Exposure to 4-OPA significantly elevated IL-8, IL-6, GM-CSF, and TNF-alpha while glutaraldehyde caused significant elevations in IL-6, IL-8, and TNF-alpha. IL-6 and IL-8 were also significantly elevated after exposure to diacetyl, glyoxal, and methyl glyoxal. These studies suggest that exposure to structurally similar oxygenated reaction products may be contributing to some of the health effects associated with indoor environments and may provide an in vitro method for identification and characterization of these potential hazards.

Nano Aerosol Chamber forIn-VitroToxicity (NACIVT) studies

“…Cultex CG, Vitrocell, BAT) deposit particles from a continuous aerosol flow by diffusion and/or gravitational deposition onto cell cultures (Anderson et al, 2010;Aufderheide & Mohr, 1999;Muller et al, 2010;Phillips et al, 2005). Only few (e.g.…”

The Gillings Sampler – An electrostatic air sampler as an alternative method for aerosol in vitro exposure studies

“…Various ALI exposure systems have been developed both in-house and commercially (Table 1) [6, 9, 12-18]. Each of the exposure systems shown in Table 1 uses different mechanisms to deposit particles, which include diffusion, sedimentation, cloud settling, and electrostatic precipitation.…”

Toxicological analysis of limonene reaction products using an in vitro exposure system

“…Recent advances in the field include the development of air/cell interface exposure systems such as those produced by companies including Vitrocell ® Systems (Waldkirch, Germany) and Cultex Laboratories (Hannover, Germany). These exposure systems allow for direct exposure (flowing system) of the apical surface of the cell line or tissue with the aerosolized compound of interest, eliminating the potential for chemical/media interactions (Anderson et al, 2010; Persoz et al, 2010; Schmalz et al, 2011). While these systems are highly efficient and sensitive they are often expensive and most do not easily allow for dose response studies.…”

“…In vitro investigations into the specific health effects associated with exposure to secondary pollutants in the indoor environment are limited. One study conducted by Anderson et al (2010) demonstrated that exposure of A549 cells (Vitrocell ® for 4 h) to structurally similar terpene ozonolysis reaction products (dicarbonyl compounds) resulted in an increased pro-inflammatory response suggesting the potential for toxicity of secondary pollutants. The differences in exposure techniques and endpoints among the above mentioned studies emphasize the need for the standardization of this type of model.…”