Regulatory T cells contribute to the immunosuppressive phenotype of neutrophils in a mouse model of chronic lymphocytic leukemia.

BACKGROUND: Impaired neutrophil activity is an important issue in chronic lymphocytic leukemia (CLL), as it contributes to a dysfunctional immune response leading to life-threatening infections in patients. Some features typical of CLL neutrophils, e.g., the B-cell-supportive secretion profile, have already been described. However, most of these studies were performed on cells isolated from peripheral blood. It is still unclear which molecular factors and cell types are involved in shaping neutrophil function and phenotype in the CLL microenvironment. Since regulatory T cells (Treg) play an important role in CLL progression and influence the activity of neutrophils, we investigated the crosstalk between Treg and neutrophils in the spleen using a murine model of CLL. METHODS: In this work, we used an Eµ-TCL1 mouse model of human CLL. For our in vivo and ex vivo experiments, we inoculated wild-type mice with TCL1 leukemic cells isolated from Eµ-TCL1 transgenic mice and then monitored disease progression by detecting leukemic cells in peripheral blood. We analyzed both the phenotype and activity of neutrophils isolated from the spleens of TCL1 leukemia-bearing mice. To investigate the interrelation between Treg and neutrophils in the leukemia microenvironment, we performed experiments using TCL1-injected DEREG mice with Treg depletion or RAG2KO mice with adoptively transferred TCL1 cells alone or together with Treg. RESULTS: The obtained results underline the plasticity of the neutrophil phenotype, observed under the influence of leukemic cells alone and depending on the presence of Treg. In particular, Treg affect the expression of CD62L and IL-4 receptor in neutrophils, both of which are crucial for the function of these cells. Additionally, we show that Treg depletion and IL-10 neutralization induce changes in the leukemia microenvironment, partially restoring the "healthy" phenotype of neutrophils. CONCLUSIONS: Altogether, the results indicate that the crosstalk between Treg and neutrophils in CLL may play an important role in CLL progression by interfering with the immune response.

Time-resolved 3D imaging of two-phase fluid flow inside a steel fuel injector using synchrotron X-ray tomography.

The multiphase flow inside a diesel injection nozzle is imaged using synchrotron X-rays from the Advanced Photon Source at Argonne National Laboratory. Through acquisitions performed at several viewing angles and subsequent tomographic reconstruction, in-situ 3D visualization is achieved for the first time inside a steel injector at engine-like operating conditions. The morphology of the internal flow reveals strong flow separation and vapor-filled cavities (cavitation), the degree of which correlates with the nozzle's asymmetric inlet corner profile. Micron-scale surface features, which are artifacts of manufacturing, are shown to influence the morphology of the resulting liquid-gas interface. The data obtained at 0.1 ms time resolution exposes transient flow features and the flow development timescales are shown to be correlated with in-situ imaging of the fuel injector's hydraulically-actuated valve (needle). As more than 98.5% of the X-ray photon flux is attenuated within the steel injector body itself, we are posed with a unique challenge for imaging the flow within. Time-resolved imaging under these low-light conditions is achieved by exploiting both the refractive and absorptive properties of X-ray photons. The data-processing strategy converted these images with a signal-to-noise ratio of ~ 10 into a meaningful dataset for understanding internal flow and cavitation in a nozzle of diameter 200 µm enclosed within 1-2 millimeters of steel.

Drug distribution transients in solution and suspension-based pressurised metered dose inhaler sprays.

This paper presents in situ time-resolved drug mass fraction measurements in pressurised metered dose inhaler (PMDI) sprays, using a novel combination of synchrotron X-ray fluorescence and scattering. Equivalent suspension and solution formulations of ipratropium bromide in HFA-134a propellant were considered. Measurements were made both inside the expansion chamber behind the nozzle orifice, and in the first few millimeters of the spray where droplet and particle formation occur. We observed a consistent spike in drug mass fraction at the beginning of the spray when the first fluid exits the nozzle orifice. Approximately 20% of the total delivered dose exits the nozzle in the first 0.1 s of the spray. The drug mass fraction in the droplets immediately upon exiting the nozzle peaked at approximately 50% of the canister mass fraction, asymptoting to approximately 20% of the canister concentration. The effect is due to a change in the drug mass fraction inside the droplets, rather than changes in droplet size or distribution. The transient was found to originate inside the expansion chamber. We propose that this effect may be a major contributor to low delivery efficiency in PMDIs, and have important implications for oropharyngeal deposition and inhalation technique. This highlights the importance of expansion chamber and nozzle design on the structure of PMDI sprays, and indicates areas of focus that may lead to improvement in drug delivery outcomes.

A rat model to study maternal depression during pregnancy and postpartum periods, its comorbidity with cardiovascular diseases and neurodevelopmental impact in the offspring.

This study aimed to develop an animal model of human depression during pregnancy and lactation to examine the effect of maternal, perinatal depression on offspring development. Maternal depression during pregnancy affects up to 20% of women and is a risk factor for both the developmental and long-term health issues. It is often comorbid with the cardiovascular disease (CVD) that affects the uteroplacental circulation and impacts offspring development. More than half of the expecting mothers with depression use antidepressants that cross the placenta and may interfere with the neurodevelopmental programming. Thus, depressed pregnant mothers face a difficult choice whether "to use or not to use" antidepressant therapy, since both untreated depression and antenatal antidepressant exposure present increased risks of neurodevelopmental pathologies. The ongoing clinical debate presents inconclusive data, while the existing animal models of maternal depression do not include early gestational periods, and, do not monitor depressive-like behavior nor address the cardiovascular abnormalities. The presented model includes pregestational depressive behavior extending into pregnancy and lactation, periods that have not been previously examined. Rat dams exposed to pre-gestational chronic mild stress (CMS) developed a sustained decrease in self-grooming behavior, correlated with hormonal, behavioral, and cardiac changes persisting through the postpartum period. Preliminary data indicate neurodevelopmental delays, behavioral and cardiac abnormalities, and altered levels of both the brain and the heart markers in the offspring of stressed dams. Furthermore, the preliminary data predict that maternal pregnancy during the perinatal period is likely to impact the neurodevelopmental process in a sex-dependent manner. Thus the presented here model (PG-LAC CMS) fulfills both the face and the construct validity criteria for maternal stress-induced depression during pregnancy and postpartum that may facilitate further studies of the relative risks of untreated vs. antidepressant-treated maternal depression during pregnancy to the mother and her offspring.

Effect of dimethyl fumarate on heme oxygenase-1 expression in experimental allergic encephalomyelitis in rats.

Multiple sclerosis (MS) is an autoimmunological disease leading to neurodegeneration. The etiology of the disease remains unknown, which strongly impedes the development of effective therapy. Most MS treatments focus on modulating the activity of the immune system. Dimethyl fumarate (DMF) exerts a broad spectrum of action, such as modulating immune cell differentiation towards anti-inflammatory subtypes, influencing cytokine production, regulating immune cell migration into the central nervous system, and activating intracellular antioxidant mechanisms. It is well established that activation of the nuclear factor E2 (Nrf2)-dependent pathway, leading to expression of the second-phase antioxidant enzymes, is influenced by DMF. In our experiments we used female Lewis rats in an animal model of MS - experimental allergic encephalomyelitis (EAE). The rats were fed with dimethyl fumarate to test the expression of heme oxygenase-1 (HO-1), one of the second-phase antioxidant enzymes, at specific time points of the symptomatic phases of the disease: on the first day of the occurrence of clinical symptoms (10th day post immunization, DPI); at the peak of clinical symptoms (14th DPI); and at the end of the relapse (21st DPI). The results showed that HO-1 expression, at both the mRNA and protein level, is influenced by DMF administration only at the very beginning of the symptomatic phase of EAE, and not at the peak of clinical symptoms, nor at the end of the relapse. This indicates that the regulation of the Nrf2-dependent antioxidant pathway by DMF occurs at a certain time interval (early EAE/MS) and strongly underlines the importance of the earliest introduction of the therapy to the patient. .

Monolayers of poly(amido amine) dendrimers on mica - In situ streaming potential measurements.

The deposition of poly(amido amine) dendrimers on mica at various pHs was studied by the atomic force microscopy (AFM) and in situ streaming potential measurements. Bulk characteristics of dendrimers were acquired by using the dynamic light scattering (DLS) and the laser Doppler velocimetry (LDV). The hydrodynamic radius derived from DLS measurements was 5.2nm for the ionic strength of 10-2M and pH range 4-10. The electrophoretic mobility, the zeta potential and the number of electrokinetic charges per molecule were derived as a function of pH from the LDV measurements. It was revealed that the dendrimers are positively charged for pH up to 10. This promoted their deposition on negatively charged mica substrate whose kinetics was quantitatively evaluated by direct AFM imaging and streaming potential measurements interpreted in terms of the electrokinetic model. The desorption kinetics of dendrimers under flowing conditions from monolayers of various coverage was also studied. It was revealed that dendrimer deposition was partially reversible for pH above 5.8. The acid-base properties of the dendrimer monolayers deposited on mica were characterized.