Chitosan and Wnt/ß-catenin Signaling Pathways in Different Cancers.

It has been a while since the disease of cancer was discovered in 16th and 17th century but still, this disease is one of the most lethal diseases in the world, which is taking a great number of lives every year. Cancer statistics suggest that there are still a lot of improvements that we have to make in the field of cancer treatment in order to overcome this deadly disease. Currently, nanotechnology has provided some more effective methods in this field, which has gained a lot of attention. Novel drug delivery systems that work using nanoparticles might be the answer to many unsolved questions in treating cancer. Chitosan is a natural glucose polymer which has the potential to be utilized as a proper drug carrier due to its advantageous features. Chitosan-based delivery systems are able to affect cancerous cells in many pathways. Wnt signaling pathways, which are one of the most essential ingredients of cancer pathogenesis, can be the target of chitosan nanoformulations. In this paper, we discussed the specific impacts of chitosan and its nanoformulations on each component of the Wnt/catenin pathway. Our conclusions might give novel insights for designing more efficient therapeutic approaches for several kinds of cancer.

Novel heterocyclic chitosan derivatives and their derived nanoparticles: Catalytic and antibacterial properties.

The metal-assisted nitrone-nitrile cycloaddition reaction is apply to empower chitosan chemistry. The ultrasonic irradiation has proven to efficiently accelerate the cycloaddition affording new heterocyclic (1,2,4-oxadiazoline) chitosan derivatives and avoiding ultrasonic degradation of the chitosan macromolecules. By varying the nitrone nature, both water- and toluene-soluble chitosan derivatives were successfully synthesized. Relying on the ionic gelation approach nanoparticles of heterocyclic chitosan derivatives were prepared. Water-soluble chitosan derivative demonstrated a high antibacterial activity coupled with low toxicity. The toxicity of the synthesized heterocyclic chitosan derivatives and their based nanoparticles are comparable with those of the starting chitosan, while their antibacterial activity is superior. Toluene-soluble derivatives are shown to be efficient homogeneous catalysts towards monoglyceride synthesis via the epoxide ring opening. They efficiently catalyze selective conversion of fatty acids and glycidol into corresponding monoglycerides allowing one to simplify significantly the procedure for separating the reaction product from the catalyst for its recovery and reusage.

Targeting of temozolomide using magnetic nanobeads: an in vitro study

Temozolomide, a chemotherapeutic drug that is often administered for the treatment of brain cancer has severe side effects and a poor aqueous solubility. In order to decrease the detrimental effect of the drug over healthy cells, a novel drug delivery vehicle was developed where the therapeutic drug was encapsulated within the hydrophobic cavities of b-CD modified magnetite nanoparticles, which are embedded in chitosan nanobeads prepared by salt addition. In-vitro studies have shown that the magnetic properties of the novel delivery vehicle are adequate for targeted drug delivery applications under an external magnetic field. Additionally, an increase in the amount of chitosan was shown to exhibit a strong shielding effect over the magnetic properties of the delivery vehicle, which lead to deterioration of the amount of captured drug at the targeted area, suggesting a delicate balance between the amounts of constituents composing the drug delivery vehicle.

Effect of chitosan nanoparticles on the inhibition of Candida spp. biofilm on denture base surface.

OBJECTIVES: Chitosan nanoparticles (ChNPs) have antifungal effects, however there is a lack of information about the effects of ChNPs against Candida biofilm on denture base surface. This study investigated the ChNPs effect against C. albicans biofilm adhesion and formation, and against Candida spp. biofilm on heat-cured acrylic resin. DESIGN: The ChNPs were synthetized (3800 µg/mL) and characterized by infra-red spectrophotometry and transmission electron microscopy. The minimum inhibitory/fungicidal concentrations (MIC/MFC) against Candida spp. were determined. The time-kill assay and changes on C. albicans micromorphology were evaluated. The % inhibition of ChNPs on C. albicans biofilm formation and reduction were investigated using 1 min and 8 h exposure. Candida biofilm was developed on resin surfaces and ChNPs were applied every 8 h for 5 days. After, fungal cells were counted (CFU/mL) and the surface roughness (Ra) and vickers microhardness (HV) of resin were analysed. For all experiments, sodium hypochlorite (NaOCl) was used as control. Data were analyzed by ANOVA, Tukey and paired t-tests (α = 0.05). RESULTS: The MIC80% of ChNPs was 30.1 µg/mL. ChNPs at 4 MIC showed complete inhibition in the time-kill assays. Blastoconidia cells were predominant after ChNPs application. The % inhibition ChNPs on C. albicans was proportional to its concentration, regardless of the exposure time. ChNPs decreased the CFU/mL of Candida spp. and showed lower alteration of HV and Ra values of resin surface compared to NaOCl. CONCLUSIONS: The ChNPs inhibited C. albicans biofilm, reduced Candida biofilm on resin and caused small changes in roughness and hardness of acrylic resin surface.

An inhibitory action of chitosan nanoparticles against pathogenic bacteria and fungi and their potential applications as biocompatible antioxidants.

Chitosan is the second most abundant polymer obtained from the byproduct of seafood. Chitosan and its derivatives and chitosan loaded drugs are the recent area of interest against microbial pathogenesis. The cationic chitosan nanoparticles (ChNPs) interact with the anionic surfaces of the microbial cell membrane, which promotes antimicrobial activity. Although, ChNPs are potential against pathogenic microbes, selection of adaptable, suitable and cost effective synthesis method is much important. In the present study, ChNPs were synthesized adopting ionic gelation using sodium tripolyphosphate as a cross linking agent and characterized by FTIR, DLS, SEM and TEM analysis. ChNPs were investigated for antimicrobial activity against bacterial (Escherichia coli and Staphylococcus aureus) and fungal (Candida albicans) pathogens. ChNPs showed bactericidal activity at the lower minimum inhibitory concentration of about 40-80 µg mL-1. Interestingly, ChNPs exhibits biocompatible antioxidant property by inhibiting DPPH free radicals at 76% and also proven to be a potential candidate against the microbial pathogenesis with an inevitable applications in biomedicine.

Análisis comparativo de la regeneración ósea obtenida con quitosano y plasma rico en fibrina / Comparative analysis of the obtained bone regeneration with chitosan and plasma rich in fibrin

La regeneración ósea guiada (ROG) es un procedimiento que consiste en el incremento de la cantidad del hueso empleando materiales poliméricos biocompatibles como por ejemplo, el quitosano y el plasma rico en fibrina (PRF); los cuales se han valorado de manera individual con excelentes resultados. En este estudio, se propone analizar radiográficamente la regeneración ósea de ambos polímeros sobre alvéolos dentales postextracción. Se seleccionaron 5 pacientes con indicación de extracción de cordales inferiores bilaterales y a un alvéolo se aplicó quitosano y al otro PRF; se realizaron radiografías periapicales a los 15, 30, 60 y 120 días. Posteriormente, se analizaron las radiografías para observar el nivel de regeneración ósea y los resultados mostraron que ambos biomateriales regeneraron los tejidos, pero con la siguiente diferencia: la ROG con PRF ocurrió en menor tiempo mientras que la ROG con quitosano tuvo una mejor organización estructural. Se concluye que ambos biomateriales se pueden tomar como opciones de tratamientos en la regeneración ósea guiada de tejidos.

The bone regeneration it a procedure that consists in the formation of new bony tissues using biocompatible polymeric materials, among them the chitosan (natural biopolymer) and the rich fibrin plasma (PRF) this biomaterials have been studied and used to achieve the bony regeneration obtaining excellent results. The aim of this research was to design an experiment that allowing us to compare the regenerator effect of both polymers, after the extraction of dental pieces in human beings, using periapical radiography's. Five patients, with indication of extraction of the lower bilateral wisdom dental pieces were selected. Chitosan and PRF were applied on different dental sockets after surgery. To register the information, periapical Rx were taken and analyzed, the procedure were done monthly, for 120 days. The results for Rx showed that both biomaterials regenerated bony tissue. The PRF generated major quantity of tissue in minor time whereas the chitosan did it with better structural organization, so, it was possible to conclude that chitosan and PRF represents interesting options for the treatments where guided bony regeneration is required.

The effect of tissue inhibitors on the antibacterial activity of chitosan nanoparticles and photodynamic therapy.

INTRODUCTION: Newer antibacterial alternatives such as chitosan nanoparticles (CSnps) and photodynamic therapy (PDT) have been investigated to achieve effective root canal disinfection. The current study aims to assess the effect of various tissue inhibitors such as dentin, dentin matrix, pulp tissue, bacterial lipopolysaccharides (LPSs), and bovine serum albumin (BSA) on the antibacterial activity of CSnps and PDT. METHODS: The antibacterial effect of CSnps and PDT using photosensitizers, rose bengal (RB), and methylene blue (MB) were tested on planktonic Enterococcus faecalis American Type Culture Collection 29212 with or without pretreatment using different tissue inhibitors for an hour. Bacterial survival was assessed after 1, 8, and 24 hours of incubation with CSnps and after PDT using RB and MB. RESULTS: Pulp and BSA inhibited the antibacterial effect of CSnps significantly (P < .05). The antibacterial effect of CSnps was not affected by dentin, dentin matrix, or LPSs. The antibacterial activity of PDT using MB and RB was inhibited in a decreasing order by dentin matrix, BSA, pulp, dentin, and LPSs (P < .05). The effect of tissue inhibitors was higher in the case of PDT with RB. Depending on the antibacterial mechanism of CSnps and PDT, different inhibitory patterns were observed with different tissue inhibitors. CONCLUSIONS: The tissue inhibitors existing within the root canal affected the antibacterial activity of CSnps and PDT at varying degrees. Further research is required to enhance their antimicrobial efficacy in an endodontic environment.

Activation of stress-responsive mitogen-activated protein kinase pathways in hybrid poplar (Populus trichocarpa x Populus deltoides).

Plant mitogen-activated protein kinase (MAPK) cascades are important amplifying modules that can rapidly transduce stress signals into various appropriate intracellular responses. Several extracellular regulated kinase (ERK)-type MAPKs involved in plant defense signaling have been identified in herbaceous species, but no MAPK cascade has yet been characterized in a tree species. We examined the signal transduction events that lead to activation of defense mechanisms in poplar, a major forest species of economic and ecological importance which is becoming the model tree system for studying stress and adaptation responses. We show that, in poplar cell suspensions and leaf tissue, chitosan, a non-host-specific elicitor, and ozone, a strong oxidant and atmospheric pollutant, induce rapid and transient activation of at least two myelin basic protein (MBP) kinases with apparent molecular masses of 44 and 47 kD. The chitosan- and ozone-activated kinases have characteristics of MAPKs-they preferentially phosphorylate MBP, require tyrosine and threonine phosphorylation to be activated and are specifically recognized by anti-ERK and anti-pERK antibodies. Moreover, activation of these poplar MAPKs by chitosan or ozone is dependent on the production of reactive oxygen species; the influx of calcium ions via membrane channels; the activation of an upstream, membrane-localized component; and a cognate MAPK kinase (MAPKK). These data suggest that biotic and abiotic challenges activate MAPKs in poplar, as in herbaceous species, which then function as a convergence point for pathogen defense and oxidant stress signaling cascades.

Potential role of nuclear factor-kappaB in the induction of nitric oxide and tumor necrosis factor-alpha by oligochitosan in macrophages.

Oligochitosan, having an average molecular weight of 1000 Da and a degree of N-acetylation below 15%, can be obtained by either chemical or enzymic hydrolysis of chitosan. The present investigation demonstrated that oligochitosan can significantly increase the activity of inducible nitric oxide synthase (iNOS) and induce the synthesis of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) in macrophages. Moreover, nuclear factor-kappaB (NF-kappaB) protein levels in nuclear extract are increased in response to oligochitosan. Blocking NF-kappaB with specific inhibitor results in decreased levels of NO and TNF-alpha. These results indicate that NF-kappaB plays a potential role in the induction of NO and TNF-alpha by oligochitosan in macrophages.