Presence of nanosilica (E551) in commercial food products: TNF-mediated oxidative stress and altered cell cycle progression in human lung fibroblast cells

Abstract

Silica (E551) is commonly used as an anti-caking agent in food products. The morphology and the dimension of the added silica particles are not, however, usually stated on the food product label. The food industry has adapted nanotechnology using engineered nanoparticles to improve the quality of their products. However, there has been increased debate regarding the health and safety concerns related to the use of engineered nanoparticles in consumer products. In this study, we investigated the morphology and dimensions of silica (E551) particles in food. The silica content of commercial food products was determined using inductively coupled plasma optical emission spectrometry. The result indicates that 2.74-14. 45 μg/g silica was found in commercial food products; however, the daily dietary intake in increase causes adverse effects on human health. E551 was isolated from food products and the morphology, particle size, crystalline nature, and purity of the silica particles were analyzed using XRD, FTIR, TEM, EDX and DLS. The results of these analyses confirmed the presence of spherical silica nanoparticles (of amorphous nature) in food, approximately 10-50 nm in size. The effects of E551 on human lung fibroblast cell viability, intracellular ROS levels, cell cycle phase, and the expression levels of metabolic stress-responsive genes (CAT, GSTA4, TNF, CYP1A, POR, SOD1, GSTM3, GPX1, and GSR1) were studied. The results suggest that E551 induces a dose-dependent cytotoxicity and changes in ROS levels and alters the gene expression and cell cycle. Treatment with a high concentration of E551 caused significant cytotoxic effects on WI-38 cells. These findings have implications for the use of these nanoparticles in the food industry.

Is nano safe in foods? Establishing the factors impacting the gastrointestinal fate and toxicity of organic and inorganic food-grade nanoparticles

“…80 Cell culture and animal feeding studies suggest that high levels of SiO 2 nanoparticles may cause adverse effects, such as cytotoxicity and generation of ROS. 80,81 A recent study suggested that SiO 2 nanoparticles accumulate in the liver at levels that could cause a health risk. 82 Another study showed that feeding of amorphous SiO 2 nanoparticles to mice for 10 weeks increased the level of ALT (alanine aminotransferase), suggesting a potential adverse effect on the liver.…”

“…15,33,49 As a result, many biochemical functions required to maintain cell viability, such as ATP production, DNA replication, and gene expression, may be adversely affected. 33 A number of studies have reported the ability of inorganic nanoparticles to increase the generation of ROS in cells and to produce cytotoxicity, including silicon dioxide nanoparticles, 81 ZnO nanoparticles, 36,126,127 and silver nanoparticles. 15 Some inorganic nanoparticles produce toxicity by generating ions (such as Ag + from silver nanoparticles or Zn 2+ from zinc oxide nanoparticles) that interact with the normal functioning cellular components (such as proteins, nucleic acids, or lipids) required to maintain biochemical processes.…”

Understanding toxicology: mechanisms and applications

“…It is as commonly used as E551, an anti-caking agent in food products, and considered Bsafe^for human/animal consumption. A study published in 2014 (Athinarayanan et al 2014) investigated its toxic effects on WI-38 (human lung normal fibroblast) cells in terms of cell viability, intracellular ROS levels, cell cycle phase, and the expression levels of metabolic stress-responsive genes. Overall, the results from this study showed that E551 induces a dose-dependent cytotoxicity and changes in ROS levels and alters the gene expression and cell cycle.…”

In vitro assays for hazard identification of nanoparticles

“…Coff ee creamers, instant soups and seasoning mixes are products that contain the highest amount of nano-sized SiO 2 (Dekkers et al 2011). Analysis of isolated SiO 2 samples from commercial food products showed the presence of SiO 2 NPs of about 10-50 nm in size (Athinarayanan et al 2014). Also, it was demonstrated that 33% of the food additive SiO 2 (E551) consisted of 10-to 200-nm spherical particles (Dekkers et al 2011).…”

“…Human lung normal fi broblast treated with high concentrations of isolated SiO 2 containing NPs (10-50 nm), showed cellular damage, mitochondrial membrane potential depletion, and ROS generation. Th e cell cycle distribution was altered and the expression of antioxidant enzymes and stress response proteins were modulated (Athinarayanan et al 2014). …”