112 research outputs found
A human coâculture cell model incorporating microglia supports glioblastoma growth and migration, and confers resistance to cytotoxics
Despite the importance of the tumor microenvironment in regulating tumor progression, few in vitro models have been developed to understand the effects of nonâneoplastic cells and extracellular matrix (ECM) on drug resistance in glioblastoma (GBM) cells. Using CellTraceâlabeled human GBM and microglial (MG) cells, we established a 2D coâculture including various ratios of the two cell types. Viability, proliferation, migration, and drug response assays were carried out to assess the role of MG. A 3D model was then established using a hyaluronic acidâgelatin hydrogel to culture a mixture of GBM and MG and evaluate drug resistance. A contact coâculture of fluorescently labeled GBM and MG demonstrated that MG cells modestly promoted tumor cell proliferation (17%â30% increase) and greater migration of GBM cells (>1.5âfold increase). Notably, the presence of MG elicited drug resistance even when in a low ratio (10%â20%) relative to coâcultured tumor cells. The protective effect of MG on GBM was greater in the 3D model (>100% survival of GBM when challenged with cytotoxics). This new 3D human model demonstrated the influence of nonâneoplastic cells and matrix on chemoresistance of GBM cells to three agents with different mechanisms of action suggesting that such sophisticated in vitro approaches may facilitate improved preclinical testing
Oral immunogenicity in mice and sows of enterotoxigenic escherichia coli outer-membrane vesicles incorporated into zein-based nanoparticles
Enterotoxigenic Escherichia coli (ETEC) strains are a major cause of illness and death in neonatal and recently weaned pigs. The immune protection of the piglets derives from maternal colostrum, since this species does not receive maternal antibodies through the placenta. In the present study, outer membrane vesicles (OMVs) obtained from main ETEC strains involved in piglet infection (F4 and F18 serotypes), encapsulated into zein nanoparticles coated with GantrezŸŸ AN-mannosamine conjugate, were used to orally immunize mice and pregnant sows. Loaded nanoparticles were homogeneous and spherical in a shape, with a size of 220â280 nm. The diffusion of nanoparticles through porcine intestinal mucus barrier was assessed by a Multiple Particle Tracking technique, showing that these particles were able to diffuse efficiently (1.3% diffusion coefficient), validating their oral use. BALB/c mice were either orally immunized with free OMVs or encapsulated into nanoparticles (100 ”g OMVs/mouse). Results indicated that a single dose of loaded nanoparticles was able to elicit higher levels of serum specific IgG1, IgG2a and IgA, as well as intestinal IgA, with respect to the free antigens. In addition, nanoparticles induced an increase in levels of IL-2, IL-4 and IFN-Îł with respect to the administration of free OMVs. Orally immunized pregnant sows with the same formulation elicited colostrum-, serum- (IgG, IgA or IgM) and fecal- (IgA) specific antibodies and, what is most relevant, offspring suckling piglets presented specific IgG in serum. Further studies are needed to determine the infection protective capacity of this new oral subunit vaccin
Mannosylated nanoparticles for oral immunotherapy in a murine model of peanut allergy
Peanut allergy is one of the most prevalent and severe of food allergies with no available cure. The aim of this work was to evaluate the potential of an oral immunotherapy based on the use of a roasted peanut extract (PE) encapsulated in nanoparticles with immunoadjuvant properties. For this, a polymer conjugate formed by the covalent binding of mannosamine to the copolymer of methylvinyl ether and maleic anhydride was firstly synthetized and characterized. Then, the conjugate was used to prepare nanoparticles with an important capability to diffuse through the mucus layer and reach, in a large extent, the intestinal epithelium, including Peyerâs patches. Their immunotherapeutic potential was evaluated in a model of pre-sensitized CD1 mice to peanut. After completing therapy, mice underwent an intraperitoneal challenge with PE. Nanoparticle-treatment was associated with both less serious anaphylaxis symptoms and higher survival rates than control, confirming the protective effect of this formulation against the challenge
Humidified warmed CO2 treatment therapy strategies can save lives with mitigation and suppression of SARS-CoV-2 infection: an evidence review
The coronavirus disease (COVID-19) outbreak has presented enormous challenges for healthcare, societal, and economic systems worldwide. There is an urgent global need for a universal vaccine to cover all SARS-CoV-2 mutant strains to stop the current COVID-19 pandemic and the threat of an inevitable second wave of coronavirus. Carbon dioxide is safe and superior antimicrobial, which suggests it should be effective against coronaviruses and mutants thereof. Depending on the therapeutic regime, CO2 could also ameliorate other COVID-19 symptoms as it has also been reported to have antioxidant, anti-inflammation, anti-cytokine effects, and to stimulate the human immune system. Moreover, CO2 has beneficial effects on respiratory physiology, cardiovascular health, and human nervous systems. This article reviews the rationale of early treatment by inhaling safe doses of warmed humidified CO2 gas, either alone or as a carrier gas to deliver other inhaled drugs may help save lives by suppressing SARS-CoV-2 infections and excessive inflammatory responses. We suggest testing this somewhat counter-intuitive, but low tech and safe intervention for its suitability as a preventive measure and treatment against COVID-19. Overall, development and evaluation of this therapy now may provide a safe and economical tool for use not only during the current pandemic but also for any future outbreaks of respiratory diseases and related conditions
Evaluating the coefficient of thermal expansion of additive manufactured AlSi10Mg using microwave techniques
In this paper we have used laser powder bed fusion (PBF) to manufacture and characterize metal microwave components. Here we focus on a 2.5âŻGHz microwave cavity resonator, manufactured by PBF from the alloy AlSi10Mg. Of particular interest is its thermal expansion coefficient, especially since many microwave applications for PBF produced components will be in satellite systems where extreme ranges of temperature are experienced. We exploit the inherent resonant frequency dependence on cavity geometry, using a number of TM cavity modes, to determine the thermal expansion coefficient over the temperature range 6â450âŻK. Our results compare well with literature values and show that the material under test exhibits lower thermal expansion when compared with a bulk aluminium alloy alternative (6063)
Evaluating the coefficient of thermal expansion of additive manufactured AlSi10Mg using microwave techniques
In this paper we have used laser powder bed fusion (PBF) to manufacture and characterize metal microwave components. Here we focus on a 2.5âŻGHz microwave cavity resonator, manufactured by PBF from the alloy AlSi10Mg. Of particular interest is its thermal expansion coefficient, especially since many microwave applications for PBF produced components will be in satellite systems where extreme ranges of temperature are experienced. We exploit the inherent resonant frequency dependence on cavity geometry, using a number of TM cavity modes, to determine the thermal expansion coefficient over the temperature range 6â450âŻK. Our results compare well with literature values and show that the material under test exhibits lower thermal expansion when compared with a bulk aluminium alloy alternative (6063)
Evaluation of nanoparticles as oral vehicles for immunotherapy against experimental peanut allergy
The aim of this work was to evaluate the potential application of an original oral immunotherapy, based on the use of nanoparticles, against an experimentally induced peanut allergy. In this context, a roasted peanut extract, containing the main allergenic proteins, were encapsulated into poly(anhydride) nanoparticles. The resulting peanut-loaded nanoparticles (PE-NP) displayed a mean size of about 150 nm and a significantly lower surface hydrophobicity than empty nanoparticles (NP). This low hydrophobicity correlated well with a higher in vitro diffusion in pig intestinal mucus than NP and an important in vivo capability to reach the intestinal epithelium and Peyerâs patches.
The immunotherapeutic capability of PE-NP was evaluated in a model of pre-sensitized CDI mice to peanut. After completing therapy of three doses of peanut extract, either free or encapsulated into nanoparticles, mice underwent an intraperitoneal challenge. Anaphylaxis was evaluated by means of assessment of symptom scores and mouse mast cell protease-1 levels (mMCPT-1). PE-NP treatment was associated with significant lower levels of mMCPT-1, and a significant survival rate after challenge, confirming the protective effect of this formulation against the challenge. In summary, this nanoparticle-based formulation might be a valuable strategy for peanut-specific immunotherapy
Investigating detrusor muscle concentrations of oxybutynin after intravesical delivery in an Ex Vivo porcine model
Intravesical oxybutynin is highly effective in the treatment of overactive bladder. Traditionally the mechanism of action was explained by antagonism of muscarinic receptors located in the detrusor, however evidence now suggests antimuscarinics may elicit their effect by modifying afferent pathways in the mucosal region. This study aimed to investigate the bladder wall distribution of oxybutynin in an ex vivo setting providing tissue - layer specific concentrations of drug achieved after intravesical delivery. Whole ex vivo porcine bladders were intravesically instilled with 0.167 mg mLâ1 oxybutynin solution. After 60 min, tissue samples were excised, serially sectioned parallel to the urothelial surface and extracted drug quantified. Drug distribution into the urothelium, lamina propria and detrusor was determined. Oxybutynin permeated into the bladder wall at a higher rate than other drugs previously investigated (apparent transurothelial Kp = 1.36 Ă 10â5 cm sâ1). After 60 min intravesical instillation, concentrations achieved in the urothelium (298.69 ÎŒg gâ1) and lamina propria (43.65 ÎŒg gâ1) but not the detrusor (0.93 ÎŒg gâ1) were greater than reported IC50 values for oxybutynin. This work adds to the increasing body of evidence suggesting antimuscarinics elicit their effects via mechanisms other than direct inhibition of detrusor contractio
Modulation of the fate of zein nanoparticles by their coating with a GantrezÂź AN-thiamine polymer conjugate
The aim of this work was to evaluate the mucus-permeating properties of nanocarriers using zein nanoparticles
(NPZ) coated with a GantrezÂź AN-thiamine conjugate (GT). NPZ were coated by incubation at different GT-tozein ratios: 2.5% coating with GT (GT-NPZ1), 5% (GT-NPZ2) and 10% (GT-NPZ3). During the process, the GT
conjugate formed a polymer layer around the surface of zein nanoparticles. For GT-NPZ2, the thickness of this
corona was estimated between 15 and 20 nm. These nanocarriers displayed a more negative zeta potential than
uncoated NPZ. The diffusivity of nanoparticles was evaluated in pig intestinal mucus by multiple particle
tracking analysis. GT-NPZ2 displayed a 28-fold higher diffusion coefficient within the mucus layer than NPZ
particles. These results align with in vivo biodistribution studies in which NPZ displayed a localisation restricted
to the mucus layer, whereas GT-NPZ2 were capable of reaching the intestinal epithelium. The gastro-intestinal
transit of mucoadhesive (NPZ) and mucus-permeating nanoparticles (GT-NPZ2) was also found to be different.
Thus, mucoadhesive nanoparticles displayed a significant accumulation in the stomach of animals, whereas
mucus-penetrating nanoparticles appeared to exit the stomach more rapidly to access the small intestine of
animal
A Cell-based Computational Modeling Approach for Developing Site-Directed Molecular Probes
Modeling the local absorption and retention patterns of membrane-permeant small molecules in a cellular context could facilitate development of site-directed chemical agents for bioimaging or therapeutic applications. Here, we present an integrative approach to this problem, combining in silico computational models, in vitro cell based assays and in vivo biodistribution studies. To target small molecule probes to the epithelial cells of the upper airways, a multiscale computational model of the lung was first used as a screening tool, in silico. Following virtual screening, cell monolayers differentiated on microfabricated pore arrays and multilayer cultures of primary human bronchial epithelial cells differentiated in an air-liquid interface were used to test the local absorption and intracellular retention patterns of selected probes, in vitro. Lastly, experiments involving visualization of bioimaging probe distribution in the lungs after local and systemic administration were used to test the relevance of computational models and cell-based assays, in vivo. The results of in vivo experiments were consistent with the results of in silico simulations, indicating that mitochondrial accumulation of membrane permeant, hydrophilic cations can be used to maximize local exposure and retention, specifically in the upper airways after intratracheal administration
- âŠ