Determination ofin vivotoxicity andin vitrocytotoxicity of lipopolysaccharide isolated fromSalmonellaEnteritidis and its potential use for production of polyclonal antibody

Fruits of Hippophaë rhamnoides in human leukocytes and Caco-2 cell monolayer models—A question about their preventive role in lipopolysaccharide leakage and cytokine secretion in endotoxemia

Preparations from Hippophaë rhamnoides L. (sea buckthorn) have been traditionally used in the treatment of skin and digestive disorders, such as gastritis, gastric and duodenal ulcers, uterine erosions, as well as oral, rectal, and vaginal mucositis, in particular in the Himalayan and Eurasian regions. An influence of an aqueous extract from the fruits of H. rhamnoides (HR) on leakage of lipopolysaccharide (LPS) from Escherichia coli through gut epithelium developed from the human colorectal adenocarcinoma (Caco-2) monolayer in vitro and glucose transporter 2 (GLUT2) translocation were the principal objectives of the study. Additionally, the effect of HR on the production of pro- and anti-inflammatory cytokines (interleukins: IL-8, IL-1β, IL-10, IL-6; tumor necrosis factor: TNF-α) by the Caco-2 cell line, human neutrophils (PMN), and peripheral blood mononuclear cells (PBMC) was evaluated. The concentration of LPS on the apical and basolateral sides of the Caco-2 monolayer was evaluated with a Limulus Amebocyte Lysate (LAL) assay. GLUT2 translocation was evaluated using an immunostaining assay, whereas secretion of cytokines by cell cultures was established with an enzyme-linked immunosorbent (ELISA) assay. HR (500 μg/ml) significantly inhibited LPS leakage through epithelial monolayer in vitro in comparison with non-treated control. The treatment of Caco-2 cells with HR (50–100 μg/ml) showed GLUT2 expression similar to the non-treated control. HR decreased the secretion of most pro-inflammatory cytokines in all tested models. HR might prevent low-grade chronic inflammation caused by metabolic endotoxemia through the prevention of the absorption of LPS and decrease of chemotactic factors released by immune and epithelial cells, which support its use in metabolic disorders in traditional medicine.

A Novel Method of Endotoxins Removal from Chitosan Hydrogel as a Potential Bioink Component Obtained by CO2 Saturation

The article presents a new approach in the purification of chitosan (CS) hydrogel in order to remove a significant amount of endotoxins without changing its molecular weight and viscosity. Two variants of the method used to purify CS hydrogels from endotoxins were investigated using the PyroGene rFC Enzymatic Cascade assay kit. The effect of the CS purification method was assessed in terms of changes in the dynamic viscosity of its hydrogels, the molecular weight of the polymer, microbiological purity after refrigerated storage and cytotoxicity against L929 cells based on the ISO 10993-5:2009(E) standard. The proposed purification method 1 (M1) allows for the removal of significant amounts of endotoxins: 87.9–97.6% in relation to their initial concentration in the CS hydrogel without affecting the solution viscosity. Moreover, the final solutions were sterile and microbiologically stable during storage. The M1 purification method did not change the morphology of the L929 cells.

The Antimicrobial Effectiveness and Cytotoxicity of the Antibiotic-Loaded Chitosan: ECM Scaffolds

Background: The development of multifunctional wound dressings with the ability to control hemostasis, limit infection and promote rapid wound healing and constructive tissue remodeling has been a challenge for many years. In view of these challenges, a hybrid scaffold platform was developed that combined two different extracellular matrices (ECM): ECM from decellularized mammalian tissue and ECM (chitosan) from crustaceans. Both types of ECM have well established clinical benefits that support and promote wound healing and control hemostasis. This scaffold platform could also be augmented with antibiotics to provide bactericidal activity directly to the wound site. Methods: Four different scaffold formulations were developed containing chitosan supplemented with either 20% or 50% urinary bladder matrix (UBM) hydrogel or 1% (w/v) or 10% (w/v) UBM–ECM particulates. 100% chitosan scaffolds were used as controls. The scaffolds were augmented with either minocycline or rifampicin. Escherichia Coli and Staphylococcus Aureus were used to assesses antimicrobial efficacy and duration of activity, while neutral red uptake assays were performed to establish direct and indirect cytotoxicity. Results: Results showed that scaffold handling properties, scaffold integrity over time and the efficacy and release rate of loaded antibiotics could be modified by altering scaffold composition. Moreover, antibiotics were easily released from the scaffold and could remain effective for up to 24 h by modifying the scaffold composition. Variable results with cytotoxicity testing show that further work is required to optimize the scaffold formulations but these proof of principle experiments suggest that these scaffolds have potential as bioactive wound dressings.

Biodegraded magnetosomes with reduced size and heating power maintain a persistent activity against intracranial U87-Luc mouse GBM tumors

BACKGROUND

An important but rarely addressed question in nano-therapy is to know whether bio-degraded nanoparticles with reduced sizes and weakened heating power are able to maintain sufficient anti-tumor activity to fully eradicate a tumor, hence preventing tumor re-growth. To answer it, we studied magnetosomes, which are nanoparticles synthesized by magnetotactic bacteria with sufficiently large sizes (~ 30 nm on average) to enable a follow-up of nanoparticle sizes/heating power variations under two different altering conditions that do not prevent anti-tumor activity, i.e. in vitro cellular internalization and in vivo intra-tumor stay for more than 30 days.

RESULTS

When magnetosomes are internalized in U87-Luc cells by being incubated with these cells during 24 h in vitro, the dominant magnetosome sizes within the magnetosome size distribution (DMS) and specific absorption rate (SAR) strongly decrease from DMS ~ 40 nm and SAR ~ 1234 W/gFe before internalization to DMS ~ 11 nm and SAR ~ 57 W/gFe after internalization, a behavior that does not prevent internalized magnetosomes to efficiently destroy U87-Luc cell, i.e. the percentage of U87-Luc living cells incubated with magnetosomes decreases by 25% between before and after alternating magnetic field (AMF) application. When 2 µl of a suspension containing 40 µg of magnetosomes are administered to intracranial U87-Luc tumors of 2 mm3 and exposed (or not) to 15 magnetic sessions (MS), each one consisting in 30 min application of an AMF of 27 mT and 198 kHz, DMS and SAR decrease between before and after the 15 MS from ~ 40 nm and ~ 4 W/gFe down to ~ 29 nm and ~ 0 W/gFe. Although the magnetosome heating power is weakened in vivo, i.e. no measurable tumor temperature increase is observed after the sixth MS, anti-tumor activity remains persistent up to the 15th MS, resulting in full tumor disappearance among 50% of treated mice.

CONCLUSION

Here, we report sustained magnetosome anti-tumor activity under conditions of significant magnetosome size reduction and complete loss of magnetosome heating power.

Chemical and Immunological Characteristics of Aluminum-Based, Oil-Water Emulsion, and Bacterial-Origin Adjuvants

Adjuvants are a diverse family of substances whose main objective is to increase the strength, quality, and duration of the immune response caused by vaccines. The most commonly used adjuvants are aluminum-based, oil-water emulsion, and bacterial-origin adjuvants. In this paper, we will discuss how the election of adjuvants is important for the adjuvant-mediated induction of immunity for different types of vaccines. Aluminum-based adjuvants are the most commonly used, the safest, and have the best efficacy, due to the triggering of a strong humoral response, albeit generating a weak induction of cell-mediated immune response. Freund's adjuvant is the most widely used oil-water emulsion adjuvant in animal trials; it stimulates inflammation and causes aggregation and precipitation of soluble protein antigens that facilitate the uptake by antigen-presenting cells (APCs). Adjuvants of bacterial origin, such as flagellin, E. coli membranes, and monophosphoryl lipid A (MLA), are known to potentiate immune responses, but their safety and risks are the main concern of their clinical use. This minireview summarizes the mechanisms that classic and novel adjuvants produce to stimulate immune responses.

Comparison of pharmaceutical quality of eight generic ganciclovir injections in China and Cymevene

To assess the pharmaceutical quality of eight commercially available generic products of ganciclovir injection produced in China with original brand product (Cymevene, Roche, Switzerland). Tests were performed according to China Pharmacopoeia 2015 and Import Drug Registration Standard introduced by CFDA. Items including characteristics of the packing and reconstituted solution, pH, visible particles, content of active and related substances, sterility and bacterial endotoxin were all carried out based on the standard laboratory operating rules and requirements. Seven of all tested domestically produced generics of ganciclovir for injection failed to reach the in vitro quality requirements in comparison with the original brand product Cymevene. Three generics failed to meet the standards for pH of an aqueous solution. One out of eight generic products fell outside the specifications for API content. All generics showed impurities, whose levels were generally greater than observed in the brand product. One generic product was identified an endotoxin contamination. In addition, six generic products failed to reach the quality requirements of water content, which should be under 3%. Most tested ganciclovir products failed to meet the pharmaceutical quality standards for original brand product. Important items like pH, endotoxin contamination, content of API and impurities could cause clinical attention, as they directly affect the therapeutic efficacy and patient tolerance.