Diana Zárate-Triviño

New insights into the bactericidal activity of chitosan-Ag bionanocomposite: the role of the electrical conductivity.

The relationship between electrical conductivity, structure and antibacterial properties of chitosan-silver nanoparticles (CS/AgnP) biocomposites has been analyzed. To test the films antimicrobial activity, Gram-positive and Gram-negative bacteria were studied. The interactions between silver nanoparticles with chitosan suggest the formation of silver ions which plays a major role in nanocomposites bactericidal potency. In CS/AgnP biocomposites, the bactericide effectiveness increases by increasing AgnP concentrations up to 3 wt%, which is close to the electrical percolation threshold of ca. 3 wt%. As the AgnP concentration increases above this threshold, the bactericidal potency is greatly diminished. The elucidated correlation between electrical conductivity and antibacterial activity could be useful in the design of other nanocomposites that involve polymeric-based matrices.

Synthesis and characterization of a hybrid (chitosan-g-glycidyl methacrylate)–xanthan hydrogel

This work reports the synthesis and characterization of a new material obtained by mixing the hybrid natural–synthetic chitosan-g-glycidyl methacrylate (CTS–g–GMA) biopolymer and xanthan gum (X). All materials were characterized by infrared spectroscopy (FTIR), X-ray diffraction, and thermal analysis (DSC and TGA) and the results were contrasted with those of the precursor materials. The swelling index of the hydrogels decreases when the GMA mass percentage increases. The X-ray diffraction patterns show that the hybrid hydrogels are amorphous in contrast to chitosan (CTS), which is semi-crystalline. FTIR analysis confirms the existence of physical interactions among constituents. Rheological properties, η, G′, and G″, were determined as a function of flow allowing one to conclude that (CTS–g–GMA)–X behaves as physical hydrogel. Additionally, we report viability of fibroblasts when cultured onto the synthesized hydrogels. This study shows that these hydrogels support cell viability and have potential for use in biomedical engineering applications.

In Vitro Evaluation of Colloidal Silver on Immune Function

Colloidal silver AgC is currently used by humans and it can be internalized through inhalation, injection, ingestion, and dermal contact. However, there is limited information about immunological activity; more investigations using colloidal silver are needed. In the present study, the effects of AgC 17.5 ng/mL on immunological parameters proliferation and immunophenotyping using human peripheral blood mononuclear cells PBMC and macrophages phagocytosis and cytotoxicity on leukemia and lymphoma cancer cell lines 1.75 to 17.5 ng/mL were investigated. AgC was observed to significantly p<0.05 decrease interleukin-2 IL-2 production and proliferation induced by phytohemagglutinin or concanavalin A in PBMC without affecting its cell viability but with cytotoxic effect on cancer cells. IL-2, IL-4, IL-6, IL-10, INF-γ, and IL-17A cytokines production and CD3+, CD3−CD19+, CD3+CD4+, CD3+CD8+, and CD16+CD56+ PBMC phenotypes were not affected by AgC. The present study demonstrates that colloidal silver is harmless and nontoxic to the immune system cells and its ability to interfere with the immune response by decreasing cell proliferation when stimulated with mitogens demonstrated the antilymphoproliferative potential of AgC.

Chitosan gold nanoparticles induce cell death in HeLa and MCF-7 cells through reactive oxygen species production

Background Nanotechnology has gained important interest, especially in the development of new therapies; the application of gold nanoparticles (AuNPs) in the treatment and detection of diseases is a growing trend in this field. As cancer represents a serious health problem around the world, AuNPs are studied as potential drugs or drug carriers for anticancer agents. Recent studies show that AuNPs stabilized with chitosan (CH) possess interesting biological activities, including potential antitumor effects that could be selective to cancer cells. Materials and methods In this study, we synthesized sodium citrate-AuNPs and CH-capped AuNPs of 3–10 nm, and analyzed their cytotoxicity in cervical (HeLa) and breast (MCF-7) cancer cells, and in peripheral blood mononuclear cells (PBMCs). Then, we evaluated the clonogenic potential, cell cycle, nuclear alterations, caspase dependence, and reactive oxygen species (ROS) production in HeLa and MCF-7 cells after chitosan gold nanoparticles (CH-AuNPs) exposure. Results Our data showed that CH-AuNPs are cytotoxic in a dose-dependent manner in the cancer cell lines tested, while they induce low cytotoxicity in PBMCs. Sodium citrate gold nanoparticles did not show cytotoxic effects. In both HeLa and MCF-7 cell lines, CH-AuNPs inhibit clonogenic potential without inducing cell cycle arrest or nuclear alterations. The cell death mechanism is specific for the type of cancer cell line tested, as it depends on caspase activation in HeLa cells, whereas it is caspase independent in MCF-7 cells. In all cases, ROS production is mandatory for cell death induction by CH-AuNPs, as ROS inhibition with N-acetyl cysteine inhibits cell death. Conclusion Our results show that CH-AuNPs are selective for HeLa and MCF-7 cancer cells, rather than normal PBMCs, and that ROS production seems to be a conserved feature of the cell death mechanism induced by CH-AuNPs. These results improve the knowledge of CH-AuNPs and open the way to the design of new pharmacological strategies using these agents against cancer.

Immunotherapy for the treatment of canine transmissible venereal tumor based in dendritic cells pulsed with tumoral exosomes

Abstract Context: Exosomes secreted by tumor cells are a good source of cellular components that stimulate the immune response, such as alarmins (mRNA, tetraspanins (CD9, CD63, CD81), heat-shock proteins, major histocompatibility complex class I molecules) and tumor-associated antigens. These properties permit to pulsed dendritic cells in the immunotherapy for many cancers types. The aim of this study was to demonstrate the use of exosomes derived from canine transmissible venereal tumor (CTVT) as an antigen to pulsed dendritic cells and its administration in dogs with CTVT as treatment against this disease. Material and methods: From primary culture of CTVT cells the exosomes were isolated and characterized by scanning electron microscopy assay, dot blot and protein quantification. The monocytes of each patient were differentiated to dendritic cells (DC) and pulsed with CTVT exosomes (CTVTE). Phagocytosis, tumor size, populations of lymphocytes and IFN-c levels were evaluated. Results: The CTVTE showed a size around 90 nm. CD81, CD63, CD9 and Hsp70 were expressed. Monocytes showed an expression of 85.71% for CD14+, 12.3% for CD80+, 0.1% for CD83+ and 0.8% for DLA-II. In DC 5.1% for CD14+, 86.7% for CD80+, 90.1% for CD83+ and 92.6% for DLA-II and a phagocytosis of 63% was obtained by FITC Dextran test. No side effects were observed in the experimental groups with our therapy. Tumor regression was of 100% at the seventh week, as well as an increase in the level of IFN-γ (142 pg/ml), and CD4+ (28%) and CD8+ (34%) cell percentage. Discusion and conclusion: These results have shown that DC pulsed with tumor exosomes induce regression of the TVT in dogs.

Increase of the antitumour efficacy of the biocompound IMMUNEPOTENT CRP by enzymatic treatment

ABSTRACT IMMUNEPOTENT CRP is a dialyzable leukocyte extract obtained from bovine spleen with immunomodulatory and antitumour properties; therefore, when administrated as an adjuvant therapy for cancer patients, it has increased their survival and quality of life. The bioavailability of any orally administered compound can be reduced due to gastrointestinal enzymes. In this study, we evaluated if IMMUNEPOTENT CRP is resistant to the treatment with different enzymes (proteases, nucleases, polysaccharide-degrading enzymes or lipase), using as parameters for biological activity measurement its in vitro antitumour and antioxidant properties and in vivo the antitumour effect of IMMUNEPOTENT CRP treated with proteinase K. In conclusion, we consider necessary to include the antioxidant and cytotoxic activity on the MCF-7 cancer cell line as parameters for the quantitative determination of biological activity or potency tests for batch release. Additionally, the results showed that different enzymatic treatments do not affect the antitumour and antioxidant activities of IMMUNEPOTENT CRP in vitro, suggesting that this product can be administered orally without any loss of biological activity. Furthermore, IMMUNEPOTENT CRP treatment with proteinase K increases the antitumour activity in vivo.

Clinical trial evaluating the effectiveness of biocompound IMMUNEPOTENT CRP in the third-molar extraction

ABSTRACT A controlled, parallel, randomized and comparative trial was carried out to evaluate the anti-inflammatory efficacy of IMMUNEPOTENT CRP versus ibuprofen in patients after third-molar surgery over seven days. The anti-inflammatory efficacy of IMMUNEPOTENT CRP was evaluated using the method of Amin and Laskin, and the analysis of cytokine production (IL-2, IL-4, IL-6, IL-10, TNF-α, INF-γ) in saliva was done by flow cytometry. The swelling process after surgery was significant (p < 0.05) and the treatments with IMMUNEPOTENT CRP or ibuprofen controlled this process properly; no difference between the groups was found (p < 0.05). Both treatments were shown to modulate the cytokine production. These results demonstrate the anti-inflammatory activity of the natural compound IMMUNEPOTENT CRP and suggest it could be used in clinical dental practice.