Cytotoxicity and genotoxicity of chitooligosaccharides upon lymphocytes

Spray-dried pH-sensitive chitosan microparticles loaded with Mycobacterium bovis BCG intended for supporting treatment of Helicobacter pylori infection

Gram-negative spiral-shaped Helicobacter pylori (Hp) bacteria induce the development of different gastric disorders. The growing resistance of Hp to antibiotics prompts to search for new therapeutic formulations. A promising candidate is Mycobacterium bovis BCG (BCG) with immunomodulatory properties. Biodegradable mucoadhesive chitosan is a good carrier for delivering BCG mycobacteria to the gastric mucosal environment. This study aimed to show whether BCG bacilli are able to increase the phagocytic activity of Cavia porcellus-guinea pig macrophages derived from the bone marrow towards fluorescently labeled Escherichia coli. Furthermore, to encapsulate live BCG bacilli, in spray-dried chitosan microparticles (CHI-MPs), and assess the pH-dependent release of mycobacteria in pH conditions mimicking gastric (acidic) or gut (alkaline) milieu. Microparticles (MPs) were made of chitosan and coated with Pluronic F-127-(Plur) or N-Acetyl-D-Glucosamine-(GlcNAc) to increase the MPs resistance to low pH or to increase anti-Hp effect, respectively. Spray-drying method was used for microencapsulation of live BCG. The biosafety of tested CHI-MPs has been confirmed using cell models in vitro and the model of guinea pig in vivo. The CHI-MPs loaded with BCG released live mycobacteria at pH 3.0 (CHI-GlcNAc-MPs) or pH 8.0. (CHI-Plur-MPs). The CHI-MPs loaded with live BCG can be used for per os inoculation of Cavia porcellus to check the effectiveness of delivered mycobacteria in increasing anti-H. pylori host response.

Comparative Evaluation of the In Vitro Cytotoxicity of a Series of Chitosans and Chitooligosaccharides Water-Soluble at Physiological pH

Chitosans (CS) have been of great interest due to their properties and numerous applications. However, CS have poor solubility in neutral and basic media, which limits their use in these conditions. In contrast, chitooligosaccharides (COS) have better solubility in water and lower viscosity in aqueous solutions whilst maintaining interesting biological properties. CS and COS, unlike other sugars, are not single polymers with a defined structure but are groups of molecules with modifiable structural parameters, allowing the adaptation and optimization of their properties. The great versatility of CS and COS makes these molecules very attractive for different applications, such as cryopreservation. Here, we investigated the effect of the degree of polymerization (DP), degree of N-acetylation (DA) and concentration of a series of synthesized CS and COS, water-soluble at physiological pH, on their cytotoxicity in an L929 fibroblast cell culture. Our results demonstrated that CS and COS showed no sign of toxicity regarding cell viability at low concentrations (≤10 mg/mL), independently of their DP and DA, whereas a compromising effect on cell viability was observed at a high concentration (100 mg/mL).

Cytoprotective, antimutagenic/antirecombinogenic and antibacterial properties of Lallemantia iberica extracts

BACKGROUND

Plants have important chemical compounds to protect organisms from many mutagens but they may also have dangerous toxic substances that must be tested before use. Lallemantia iberica has been used by local people for treatment of some diseases but it was never tested for its cell protective and antimutagenic/antirecombinogenic properties. In this study, it was aimed to determine the cytoprotective, antimutagenic/antirecombinogenic, antibacterial, antioxidant and phenolic profile of L. iberica by MTS assay, micronucleus test/somatic mutation recombination test (SMART), disc diffusion method, ABTS/DPPH tests and liquid chromatography (LC), respectively.

RESULTS

MTS assay results showed that both of the extracts supported the normal growth of healthy human lymphocytes and there was no significant difference between extracts. Although there was no significant increase in micronucleus concentration (‰) of the cultures treated with ethanol or methanol extracts, methanol extract caused slightly lower micronucleus concentration (12.64 ± 3.65‰) than the ethanol extract (24.46 ± 4.50‰). SMART results showed that ethanol and methanol extracts prevented harmful mitotic recombination. Lallemantia iberica also showed antibacterial activity against all of the strains tested, and the largest inhibition zones were observed with Pseudomonas aeruginosa (17.9 mm) and Enterobacter aerogenes (13.8 mm). Methanol extracts showed better antioxidant activities (ABTS IC₅₀ : 104.07 μg mL^-1 , DPPH IC₅₀ : 58.8 μg mL^-1 ) than ethanol extracts (ABTS IC₅₀ : 344.03 μg mL^-1 , DPPH IC₅₀ : 233.7 μg mL^-1 ). According to the LC results, the most abundant phenolic compounds were rutin hydrate (1796.4 ± 62.9 mg kg^-1 ) and p-coumaric acid (228.1 ± 7.60 mg kg^-1 ).

CONCLUSION

Lallemantia iberica extracts had cell-protective, antimutagenic/antirecombinogenic, antibacterial and strong antioxidant characteristics in relation to their rich phenolic content. © 2022 Society of Chemical Industry.

The Role of Chitosan Oligosaccharide in Metabolic Syndrome: A Review of Possible Mechanisms

Metabolic syndrome, a cluster of metabolic disorders including central obesity, insulin resistance, hyperglycemia, dyslipidemia, and hypertension, has become a major public health problem worldwide. It is of great significance to develop natural products to prevent and treat metabolic syndrome. Chitosan oligosaccharide (COS) is an oligomer of chitosan prepared by the deacetylation of chitin, which is the second most abundant polymer in nature. In recent years, COS has received widespread attention due to its various biological activities. The present review will summarize the evidence from both in vitro and in vivo studies of the beneficial effects of COS on obesity, dyslipidemia, diabetes mellitus, hyperglycemia, and hypertension, and focus attention on possible mechanisms of the prevention and treatment of metabolic syndrome by COS.

Chitosan oligosaccharide combined with running benefited the immune status of rats

Chitosan oligosaccharide (COS) degraded by chitosan, is an easily accessible and biocompatible natural molecule, which can facilitate the immune system. Running is one of the most effective forms of exercise. Persistence in running can effectively improve the body's resistance against pathogens. However, whether the combination of COS and running could benefit immune status still remains to be elucidated. We used Sprague-Dawley (SD) rats to explore the combinatory effect of COS and running. The organs and blood of the rats were collected after four weeks and the organ body mass index, biochemical and blood routine examination, cytokines, and T cells in the spleen and blood were detected and analyzed. In the group intragastric administration of COS only, the level of blood lactate dehydrogenase was increased, while the blood creatinine, red blood cells, lymphocytes, and serum TNF were decreased. Furthermore, COS combined with running promoted the development of spleen and lung, the level of lymphocytes, T cell and CD8⁺ T cell ratio in the blood, and serum TNF level. At the same time, the level of lactate dehydrogenase, serum IL-2, and T cell ratio in spleen were decreased. Therefore, our study indicated that COS combined with running could improve the immune status of rats.

Mitochondrial and lysosomal protective agents ameliorate cytotoxicity and oxidative stress induced by cyclophosphamide and methotrexate in human blood lymphocytes

Cyclophosphamide (CYP) and methotrexate (MTX) have been evaluated for their ability to induce toxicity in human peripheral blood lymphocytes (PBLs) and the protective role of mitochondrial and lysosomal stabilizing agents. The potential toxicity effects of CYP and MTX were measured in vitro by cellular parameters assays such as cellular viability, reactive oxygen species (ROS) formation, mitochondrial membrane permeability transition (mitochondrial membrane potential (MMP)) collapse, lysosomal membrane damage, intracellular reduced glutathione (GSH), extracellular oxidized glutathione (GSSG), and lipid peroxidation. Separately, human lymphocytes were treated with concentrations of 0.1, 0.2, 0.4, 0.8, and 1.6 ng/mL for CYP and 1, 2, 5, and 10 µg/mL for MTX for 6 h. Statistical evaluations showed that CYP and MTX significantly decreased the cell viability at the three highest concentrations when compared with both the negative and solvent controls. In addition, CYP and MTX were significantly induced ROS formation, MMP collapse, lysosomal membrane damage, lipid peroxidation, and GSH depletion compared with the controls. Mitochondrial and lysosomal protective agents like cyclosporine A and chloroquine, respectively, decreased cytotoxicity and oxidative stress induced by CYP and MTX. The present results indicate that CYP and MTX are toxic to human PBLs and their toxicity could be ameliorated by mitochondrial and lysosomal protective agents.

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.

Influence of chitosan oligosaccharide on the gelling and wound healing properties of injectable hydrogels based on carboxymethyl chitosan/alginate polyelectrolyte complexes

In situ injectable hydrogels for wound healing based on carboxymethyl chitosan (CMCS) and alginate were developed in this work. The liquid mixture of CMCS and alginate solutions formed a gel by polyelectrolyte complexation after addition of d-glucono-δ-lactone (GDL), which slowly hydrolyzed and donated protons. When chitosan oligosaccharide (COS) was added into the mixture, a two-stage gelling process occurred. The primary gelling process was similar to that of the hydrogel without COS, while the secondary gelling process appeared about 20 min later, and much stronger hydrogels with storage modulus G' about 1 MPa, 10⁴ times higher, were obtained. COS also significantly influenced the microstructure of hydrogels as well as their biological activities. The hydrogels with 0.5% of COS significantly promoted proliferation of human umbilical cord mesenchymal stem cells (HUMSCs). These injectable hydrogels, especially when COS was added, remarkably accelerated the wound healing process in a mouse skin defect model. Microscopic wound analysis showed an increase of the thickness and integrity of epidermal tissue, increased formation of collagen fibers, and enhanced expression of vascular endothelial growth factor as compared to the control group.

Reactivation of wild-type and mutant p53 by tryptophanolderived oxazoloisoindolinone SLMP53-1, a novel anticancer small-molecule

Restoration of the p53 pathway, namely by reactivation of mutant (mut) p53, represents a valuable anticancer strategy. Herein, we report the identification of the enantiopure tryptophanol-derived oxazoloisoindolinone SLMP53-1 as a novel reactivator of wild-type (wt) and mut p53, using a yeast-based screening strategy. SLMP53-1 has a p53-dependent anti-proliferative activity in human wt and mut p53R280K-expressing tumor cells. Additionally, SLMP53-1 enhances p53 transcriptional activity and restores wt-like DNA binding ability to mut p53R280K. In wt/mut p53-expressing tumor cells, SLMP53-1 triggers p53 transcription-dependent and mitochondrial apoptotic pathways involving BAX, and wt/mut p53 mitochondrial translocation. SLMP53-1 inhibits the migration of wt/mut p53-expressing tumor cells, and it shows promising p53-dependent synergistic effects with conventional chemotherapeutics. In xenograft mice models, SLMP53-1 inhibits the growth of wt/mut p53-expressing tumors, but not of p53-null tumors, without apparent toxicity. Collectively, besides the potential use of SLMP53-1 as anticancer drug, the tryptophanol-derived oxazoloisoindolinone scaffold represents a promissing starting point for the development of effective p53-reactivating drugs.

Chitosan oligosaccharide: Biological activities and potential therapeutic applications

Chitosan oligosaccharide (COS) is an oligomer of β-(1➔4)-linked d-glucosamine. COS can be prepared from the deacetylation and hydrolysis of chitin, which is commonly found in the exoskeletons of arthropods and insects and the cell walls of fungi. COS is water soluble, non-cytotoxic, readily absorbed through the intestine and mainly excreted in the urine. Of particular importance, COS and its derivatives have been demonstrated to possess several biological activities including anti-inflammation, immunostimulation, anti-tumor, anti-obesity, anti-hypertension, anti-Alzheimer's disease, tissue regeneration promotion, drug and DNA delivery enhancement, anti-microbial, anti-oxidation and calcium-absorption enhancement. The mechanisms of actions of COS have been found to involve the modulation of several important pathways including the suppression of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPK) and the activation of AMP-activated protein kinase (AMPK). This review summarizes the current knowledge of the preparation methods, pharmacokinetic profiles, biological activities, potential therapeutic applications and safety profiles of COS and its derivatives. In addition, future research directions are discussed.

The potential role of free chitosan in bone trauma and bone cancer management

Bone defects caused by fractures or cancer-mediated destruction are debilitating. Chitosan is commonly used in scaffold matrices for bone healing, but rarely as a free drug. We demonstrate that free chitosan promotes osteoblast proliferation and osteogenesis in mesenchymal stem cells, increases osteopontin and collagen I expression, and reduces osteoclastogenesis. Chitosan inhibits invasion of endothelial cells, downregulating uPA/R, MT1-MMP, cdc42 and Rac1. Better healing of bone fractures with greater trabecular bone formation was observed in mice treated with chitosan. Chitosan induces apoptosis in osteotropic prostate and breast cancer cells via caspase-2 and -3 activation, and reduces their establishment in bone. Chitosan is pro-apoptotic in osteosarcoma cells, but not their normal counterpart, osteoblasts, or chondrosarcoma cells. Systemic delivery of chitosan does not perturb angiogenesis, bone volume or instinctive behaviour in pregnant mice, but decreases foetal length and changes pancreatic secretory acini. With certain controls in place, chitosan could be useful for bone trauma management.

Transcutaneous treatment with vetdrop(®) sustains the adjacent cartilage in a microfracturing joint defect model in sheep

The significance of the adjacent cartilage in cartilage defect healing is not yet completely understood. Furthermore, it is unknown if the adjacent cartilage can somehow be influenced into responding after cartilage damage. The present study was undertaken to investigate whether the adjacent cartilage can be better sustained after microfracturing in a cartilage defect model in the stifle joint of sheep using a transcutaneous treatment concept (Vetdrop^®).

Carprofen and chito-oligosaccharids were added either as single components or as a mixture to a vehicle suspension consisting of a herbal carrier oil in a water-in-oil phase. This mixture was administered onto the skin with the aid of a specific applicator during 6 weeks in 28 sheep, allocated into 6 different groups, that underwent microfracturing surgery either on the left or the right medial femoral condyle. Two groups served as control and were either treated intravenously or sham treated with oxygen only. Sheep were sacrificed and their medial condyle histologically evaluated qualitatively and semi-quantitatively according to 4 different scoring systems (Mankin, ICRS, Little and O’Driscoll).

The adjacent cartilage of animals of group 4 treated transcutaneously with vehicle, chito-oligosaccharids and carprofen had better histological scores compared to all the other groups (Mankin 3.3±0.8, ICRS 15.7±0.7, Little 9.0±1.4).

Complete defect filling was absent from the transcutaneous treatment groups.

The experiment suggests that the adjacent cartilage is susceptible to treatment and that the combination of vehicle, chitooligosaccharids and carprofen may sustain the adjacent cartilage during the recovery period.

Biocompatibility of chitosan carriers with application in drug delivery

Chitosan is one of the most used polysaccharides in the design of drug delivery strategies for administration of either biomacromolecules or low molecular weight drugs. For these purposes, it is frequently used as matrix forming material in both nano and micron-sized particles. In addition to its interesting physicochemical and biopharmaceutical properties, which include high mucoadhesion and a great capacity to produce drug delivery systems, ensuring the biocompatibility of the drug delivery vehicles is a highly relevant issue. Nevertheless, this subject is not addressed as frequently as desired and even though the application of chitosan carriers has been widely explored, the demonstration of systems biocompatibility is still in its infancy. In this review, addressing the biocompatibility of chitosan carriers with application in drug delivery is discussed and the methods used in vitro and in vivo, exploring the effect of different variables, are described. We further provide a discussion on the pros and cons of used methodologies, as well as on the difficulties arising from the absence of standardization of procedures.