TiO₂ NPs Induce DNA Damage in Lymphocytes from Healthy Individuals and Patients with Respiratory Diseases—An Ex Vivo/In Vitro Study

Abstract

Little is known of the effects of nanoparticles in human systems, let alone in diseased individuals and nanotechnology has preceded nanotoxicology. Therefore, the effects of titanium dioxide (TiO2) nanoparticles in peripheral blood lymphocytes from patients with respiratory diseases [lung cancer, chronic obstructive pulmonary disease (COPD) and asthma] were compared with those in healthy Individuals, to determine differences in sensitivity to nanochemical insult. The Comet assay was performed according to recommended guidelines. The micronucleus assay and ras oncoprotein detection were conducted according to published standard methods. The results showed statistically significant concentration-dependent genotoxic effects of TiO2 NPs in both respiratory patient and control groups in the Comet assay. The TiO2 NPs caused DNA damage in a concentration dependent manner in both groups (respiratory and healthy controls) with the exception of the lowest TiO2 concentration (10 μg/ml) which did not induce significant damage in healthy controls (n.s). When OTM data were used to compare the whole patient group and the control group, the patient group had more DNA damage (p > 0.001) with the exception of 10 μg/ml of TiO2 that caused less significant damage to patient lymphocytes (p < 0.05). Similarly, there was an increase in the pattern of cytogenetic damage measured in the MN assay without statistical significance except when compared to the negative control of healthy individuals. Furthermore, when modulation of ras p21 expression was investigated, regardless of TiO2 treatment, only lung cancer and COPD patients expressed measurable ras p21 levels. Results were achieved in the absence of cytotoxicity.

Safety assessment of titanium dioxide (E171) as a food additive

“…Positive results in cultures of human peripheral lymphocytes were also reported in two studies with limited relevance (Turkez and Geyikoglu, 2007; Kang et al., 2008). Negative or equivocal results were described in four studies classified at high or limited relevance (NANOGENOTOX Project 2013 Documentation provided to EFSA No 7 and 8; Tavares et al., 2014; Andreoli et al., 2018; Osman et al., 2018)).…”

Genotoxicity and Immunotoxicity of Titanium Dioxide-Embedded Mesoporous Silica Nanoparticles (TiO2@MSN) in Primary Peripheral Human Blood Mononuclear Cells (PBMC)

“…In chronically exposed rodents, TiO 2 induces proinflammatory cytokines and fibrosis of the lung [45], and TiO 2 NPs appear to play a role in the onset and aggravation of allergies through a cyto-genotoxic mechanism [46]. Also, human lymphocytes, either from healthy individuals or with respiratory disease, are damaged by TiO 2 NPs at the DNA level [47]. Human studies, regarding professionally exposed worker to TiO 2 (nanoparticles), show oxidative damage of nucleic acids of Ti-containing exhaled breath condensate samples [48] and increased oxidative stress and overexpression of inflammatory and fibrogenic cytokines [49].…”