Genotoxicity evaluation of stearic acid grafted chitosan oligosaccharide nanomicelles

Oxidative stress and cyto-genotoxicity induced by poly-d-glucosamine in human blood cells in vitro

Poly-N-acetyl-d-glucosamine (CH; chitin) is the main component of the insect skeleton, fungal cell wall, and many crustaceans, including crab and shrimp. CH is the most abundant in nature after cellulose, and it has a complex and hardly soluble structure. Poly-d-glucosamine (CHO; chitosan) is a soluble derivative of CH produced by deacetylation used in many fields, including human health. This study carried out the cytotoxic, genotoxic, and oxidative effects of CHO on human whole blood (hWB) and lymphocytes (LYMs) in dose ranges 6.25-2000 μg/mL, in vitro. Total antioxidant capacity (TAC) and total oxidant status (TOS) analyzes were performed on plasma to appreciate oxidative stress. 3-(4,5-Dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays were applied to understand the cytotoxicity. Chromosomal aberration (CA) and micronucleus (MN) methods were practiced to evaluate genotoxicity. 6.25-150 μg/mL doses increased TAC and decreased TOS. A decreasing and increasing curve from 200 to 2000 μg/mL on TAC and TOS values were determined, respectively. 0-250 μg/mL doses did not provide any cytotoxic data. However, 500-2000 μg/mL doses showed increasing cytotoxicity and genotoxicity. The study results showed that CHO does not pose a toxic risk to human health at low doses but may pose a threat at high doses.

Phytotoxicity, cytotoxicity, and in vivo antifungal efficacy of chitosan nanobiocomposites on prokaryotic and eukaryotic cells

Chitosan (CS) nanosystems have potential applications for the control of microorganisms in the medical, environmental, and agrifood fields. In vivo and in vitro assays of CS nanosystems have experienced increased activity due to improved physicochemical properties, biological activity, and reactivity. Hence, it is important to determine whether their application involves toxicological risks. The aim of this study was to evaluate the mutagenic, cytotoxic, phytotoxic, and in vivo antifungal activity of chitosan-pyrrole-2-carboxylic acid nanobiocomposites (CS-PCA). The CS-PCA nanoparticles were synthesized by means of the nanoprecipitation technique with a size and ζ-potential of 502 ± 72 nm and + 54.7 ± 15.0 mV, respectively. According to the Ames test, no evidence of mutagenic activity was observed in Salmonella typhimurium strains. The cytotoxic assay showed that the incorporation of PCA into the CS matrix increased the toxic effect on ARPE-19 cells. However, fluorescence microscopy of ARPE-19 cells did not reveal morphostructural changes allusive to cell injury. CS-PCA exhibited strong phytotoxicity on lettuce seeds and the complete inhibition of seed development. The antifungal assay demonstrated that the CS-PCA delayed Aspergillus niger infection in tomato fruit until day 3; however, its use for the pre-treatment of seeds might exert adverse effects on plant development.

Brain-Targeted Delivery of Pre-miR-29b Using Lactoferrin-Stearic Acid-Modified-Chitosan/Polyethyleneimine Polyplexes

The efficacy of brain therapeutics is largely hampered by the presence of the blood–brain barrier (BBB), mainly due to the failure of most (bio) pharmaceuticals to cross it. Accordingly, this study aims to develop nanocarriers for targeted delivery of recombinant precursor microRNA (pre-miR-29b), foreseeing a decrease in the expression of the BACE1 protein, with potential implications in Alzheimer’s disease (AD) treatment. Stearic acid (SA) and lactoferrin (Lf) were successfully exploited as brain-targeting ligands to modify cationic polymers (chitosan (CS) or polyethyleneimine (PEI)), and its BBB penetration behavior was evaluated. The intracellular uptake of the dual-targeting drug delivery systems by neuronal cell models, as well as the gene silencing efficiency of recombinant pre-miR-29b, was analyzed in vitro. Labeled pre-miR-29b-CS/PEI-SA-Lf systems showed very strong fluorescence in the cytoplasm and nucleus of RBE4 cells, being verified the delivery of pre-miR-29b to neuronal cells after 1 h transfection. The experiment of transport across the BBB showed that CS-SA-Lf delivered 65% of recombinant pre-miR-29b in a period of 4 h, a significantly higher transport ratio than the 42% found for PEI-SA-Lf in the same time frame. Overall, a novel procedure for the dual targeting of DDS is disclosed, opening new perspectives in nanomedicines delivery, whereby a novel drug delivery system harvests the merits and properties of the different immobilized ligands.

Effects of Stearic Acid on Proliferation, Differentiation, Apoptosis, and Autophagy in Porcine Intestinal Epithelial Cells

BACKGROUND

Stearic acid (SA), a saturated long-chain fatty acid consisting of 18 carbon atoms, is widely found in feed ingredients, such as corn, soybeans, and wheat. However, the roles of SA in the renewal of intestinal epithelial cells remain unclear.

METHODS AND RESULTS

In the present study, we found that 0.01-0.1 mM SA promoted IPEC-J2 cell differentiation and did not affect IPEC-J2 cell viability. In addition, the results showed that the viability of IPEC-J2 cells was inhibited by SA in a time- and dose-dependent manner at high concentrations. Flow cytometry and western blot analysis suggested that SA induced apoptosis, autophagy and ER stress in cells. In addition, the amounts of triglyceride were significantly increased upon challenge with SA. Moreover, the decrease in the viability of cells induced by SA could be attenuated by 4-PBA, an inhibitor of ER stress.

CONCLUSION

In summary, SA accelerated IPEC-J2 cell differentiation at 0.01-0.1 mM. Furthermore, SA induced IPEC-J2 cell apoptosis and autophagy by causing ER stress.

Genotoxicity Assessment of Nanomaterials: Recommendations on Best Practices, Assays, and Methods

Nanomaterials (NMs) present unique challenges in safety evaluation. An international working group, the Genetic Toxicology Technical Committee of the International Life Sciences Institute's Health and Environmental Sciences Institute, has addressed issues related to the genotoxicity assessment of NMs. A critical review of published data has been followed by recommendations on methods alterations and best practices for the standard genotoxicity assays: bacterial reverse mutation (Ames); in vitro mammalian assays for mutations, chromosomal aberrations, micronucleus induction, or DNA strand breaks (comet); and in vivo assays for genetic damage (micronucleus, comet and transgenic mutation assays). The analysis found a great diversity of tests and systems used for in vitro assays; many did not meet criteria for a valid test, and/or did not use validated cells and methods in the Organization for Economic Co-operation and Development Test Guidelines, and so these results could not be interpreted. In vivo assays were less common but better performed. It was not possible to develop conclusions on test system agreement, NM activity, or mechanism of action. However, the limited responses observed for most NMs were consistent with indirect genotoxic effects, rather than direct interaction of NMs with DNA. We propose a revised genotoxicity test battery for NMs that includes in vitro mammalian cell mutagenicity and clastogenicity assessments; in vivo assessments would be added only if warranted by information on specific organ exposure or sequestration of NMs. The bacterial assays are generally uninformative for NMs due to limited particle uptake and possible lack of mechanistic relevance, and are thus omitted in our recommended test battery for NM assessment. Recommendations include NM characterization in the test medium, verification of uptake into target cells, and limited assay-specific methods alterations to avoid interference with uptake or endpoint analysis. These recommendations are summarized in a Roadmap guideline for testing.

Assessment of toxicity and oxidative DNA damage of sodium hypochlorite, chitosan and propolis on fibroblast cells

The objective of this study was to evaluate and compare the cytotoxicity and genotoxicity on human fibroblast cell lines of sodium hypochlorite (NaOCl), chitosan and propolis as root canal irrigating solutions. Human fibroblast cells were exposed to chitosan, propolis and NaOCl for 4 and 24 h. Cell viability was assessed by 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide, and oxidative DNA damage was assessed by determination of 8-hydroxydeoxyguanosine (8-OHdG) level with an ELISA kit. The data of cell cytotoxicity were analysed statistically using a test of one-way analysis of variance at a significance level of p < 0.05. In the NaOCI group, the 8-OHdG level was higher than in the chitosan group, but there was no statistical difference when compared with the other groups (p < 0.05). It was determined that the irrigation solutions were cytotoxic, depending on the dose and time. NaOCl was the most toxic solution after both 4 and 24 h of exposure (p < 0.05). Chitosan and propolis may be alternatives to NaOCl for irrigation solutions, because they are both less toxic and produce less oxidative DNA damage.

Chitosan-Stearic Acid Based Polymeric Micelles for the Effective Delivery of Tamoxifen: Cytotoxic and Pharmacokinetic Evaluation

Chitosan is a widely employed polysaccharide with positive zeta-potential and better tissue/cell adhesion. Its hydrophilicity, high viscosity, and insolubility at physiological pH are major hurdles in proper utilization of this macromolecule. Therefore, it was conjugated with biocompatible stearic acid and the conjugate was employed to develop polymeric micelles for delivery of tamoxifen to breast cancer cells. The conjugate was characterized by FT-IR and NMR, and the nanocarrier was characterized for micromeritics, surface charge, drug loading, and morphological attributes. The efficacy was evaluated by in vitro MTT studies, safety by erythrocyte compatibility, and biodistribution by in vivo pharmacokinetic studies. Despite better drug loading and sustained drug release, cytotoxicity on MCF-7 breast cancer cells was substantially enhanced and the pharmacokinetic profile was significantly modified. The AUC was enhanced manifolds along with reduced clearance. The findings are unique and provide an alternative to the conventional lipid-based nanocarriers for better dose delivery, tissue adhesion, and desired pharmacokinetic modulation.

Synthesis and characterization of curcumin loaded polymer/lipid based nanoparticles and evaluation of their antitumor effects on MCF-7 cells

BACKGROUND

Hybrid materials are synthesized using hydrophilic polymer and lipids which ensure their long term systemic circulation through intravenous administration and enhance loading of hydrophobic drugs. The purpose of this study is to prepare, characterize and evaluate the in vitro efficacy of curcumin loaded poly-hydroxyethyl methacrylate/stearic acid nanoparticles in MCF-7.

METHODS

C-PSA-NPs, prepared using the emulsification-solvent evaporation method were characterized by dynamic laser scattering, SEM, AFM, FT-IR, X-ray diffraction, and TGA. The in vitro release behavior was observed in PBS pH7.4, the anticancer potential was analyzed by MTT assay, cell cycle and apoptosis studies were performed through flow cytometry. C-PSA-NPs drug localization and cancer cell morphological changes were analyzed in MCF-7 cell line.

RESULTS

C-PSA-NPs exhibited the mean particle size in the range of 184nm with no aggregation. The surface charge of the material was around -29.3mV. Thermal studies (TGA) and surface chemistry studies (FT-IR, XRD) showed the existence of drug curcumin in C-PSA-NPs. The MTT assay indicated higher anticancer properties and flow cytometry studies revealed that there were better apoptotic activity and maximum localization of C-PSA-NPs than curcumin.

CONCLUSIONS

Polymer lipid based drug delivery appeared as one of the advancements in drug delivery systems. Through the present study, a novel polymer lipid based nanocarrier delivery system loaded with curcumin was demonstrated as an effective and potential alternative method for tumor treatment in MCF-7 cell line.

GENERAL SIGNIFICANCE

C-PSA-NPs exhibited potent anticancer activity in MCF-7 cell line and it indicates that C-PSA-NPs are a suitable carrier for curcumin.