Mexican researchers sought to evaluate the effects of E171 across a span of conditions in mice, including its influence on behavior, along with the effects on the colon and liver. The research, published in 2020 in the journal Food and Chemical Toxicology, showed that E171 promoted anxiety and induced adenomas, or noncancerous tumors, in the colon. They also found that E171 heightened goblet cells hypertrophy and hyperplasia, which is typically seen in asthma patients and triggered by smoking or external pollutants and toxins. They also noted mucins overexpression in the mice, which can be linked to cancer cell formation.
Recently, Yanagisawa et al. reported that the transdermal exposure (mimicking skin-barrier dysfunction or defect) of NC/Nga mice to TiO2 NPs (15, 50, or 100 nm), in combination with allergen, aggravated atopic dermatitis-like lesions through a T-helper type 2 (Th2) dominant immune response. The study also indicated that TiO2 NPs can play a role in the initiation and/or progression of skin diseases, since histamine was released, even in the absence of allergen.