Assessing the Genotoxicity of Cellulose Nanomaterials in a Co-Culture of Human Lung Epithelial Cells and Monocyte-Derived Macrophages

Evaluation of the cyto- and genotoxicity of two types of cellulose nanomaterials using human intestinal cells and in vitro digestion simulation

Emerging cellulose nanomaterials (CNMs) may have commercial impacts in multiple sectors, being their application particularly explored in the food sector. Thus, their potential adverse effects in the gastrointestinal tract should be evaluated before marketing. This work aimed to assess the safety of two CNMs (CNF-TEMPO and CMF-ENZ) through the investigation of their cytotoxicity, genotoxicity (comet and micronucleus assays), and capacity to induce reactive oxygen species in human intestinal cells, and their mutagenic effect using the Hprt gene mutation assay. Each toxicity endpoint was analysed after cells exposure to a concentration-range of each CNM or to its digested product, obtained by the application of a standardized static in vitro digestion method. The results showed an absence of cytotoxic effects in intestinal cells, up to the highest concentration tested (200 µg/mL or 25 µg/mL, for non-digested and digested CNMs, respectively). Of note, the cytotoxicity of the digestion control limited the top concentration of digested samples (25 µg/mL) for subsequent assays. Application of a battery of in vitro assays showed that CNF-TEMPO and CMF-ENZ do not induce gene mutations or aneugenic/clastogenic effects. However, due to the observed DNA damage induction, a genotoxic potential cannot be excluded, even though in vitro digestion seems to attenuate the effect. The lowest digested CNF-TEMPO concentration induced chromosomal damage in Caco-2 cells, leading to an equivocal outcome. Ongoing research on epigenotoxic effects of these CNMs samples may strengthen the lines of evidence on their safety when ingested, paving the way for their innovative application in the food industry.

Micronuclei as genotoxicity endpoint applied in the co-culture of two mammalian cell lines

There has been a shift from traditional animal models towards alternative methods. While 2D cell culture has a decade long tradition, more advances methods like 3D cultures, organoids, and co-culture techniques, which better mimic in vivo conditions, are not yet well established in every research area. Genotoxicity assessment is an integral part of toxicological testing or regulatory approval of pharmaceuticals and chemicals. The micronucleus assay is now a standard method in this context. In this systematic literature review, we aim to describe the state of the art of the application of co-cultures of two mammalian cell lines for micronucleus assessment. We summarized the cell types used, methods for co-culture, disease models and agents, as well as the application of additional genotoxicity endpoints and viability tests. Airway system cells were the most frequent, followed by macrophage-like cells, liver cells, and various others. Co-culture techniques involve either direct physical contact or separation by porous membranes. Within a limited number of investigations using other genotoxicity assays like the comet and γH2AX assays in parallel, the micronucleus assay performed well. Overall, the micronucleus test demonstrating its suitability in disease models and for a more complex substance testing beyond simple 2D cultures, encouraging a more widespread use in co-culture systems in the future.

Safety of Innovative Nanotechnology Oral Formulations Loaded with Bioactive Menopause Molecules: Influence of Genotoxicity and Biochemical Parameters on a Menopausal Rat Model

In recent years, nanoparticles have gained significant importance due to their unique properties, such as pharmacological, electrical, optical, and magnetic abilities, contributing to the growth of the science and technology sector. Particular naturally derived biomolecules with beneficial effects on menopause disorder have been the subject of studies of pharmaceutical formulation to obtain alternative pharmaceutical forms with increased bioavailability and without side effects, as in nanostructured lipid carriers (NLCs) loaded with such active ingredients. In the present study, one stage of a broader project, we have performed pharmacotoxicology studies for six combinatory innovative nanocapsule pharmaceutical forms containing active natural biomolecules before considering them as oral formulas for (1) in vitro toxicity studies on culture cells and (2) in vivo preclinical studies on a surgically induced menopause model of Wistar female rats, and the influence of the NLCs on key biochemical parameters: lipid profile (TG, Chol, HDL), glycemic markers (Gli), bone markers (Pac, Palc, Ca, phosphorus), renal markers (Crea, urea, URAC), inflammation (TNF), oxidative stress (GSH, MDA), and estrogen-progesterone hormonal profile. The micronucleus test did not reveal the genotoxicity of the tested compounds; the menopause model showed no significant safety concerns for the six tested formulas evaluated using the blood biochemical parameters; and the results showed the potential hypoglycemic, hypolipidemic, hypouricemic, and antioxidant potential of one of the tested formulas containing nano diosgenin and glycyrrhizic acid.