Siglec-8 in eosinophilic disorders: receptor expression and targeting using chimeric antibodies

Publication date: Available online 10 December 2018

Source: Journal of Allergy and Clinical Immunology

Author(s): Fanny Legrand, Yun Cao, Joshua Wechsler, Xiang Zhu, Nives Zimmermann, Shakuntala Rampertaap, Joseph Monsale, Kimberly Romito, Bradford A. Youngblood, Emily C. Brock, Michelle Makiya, Nenad Tomasevic, Christopher Bebbington, Irina Maric, Dean D. Metcalfe, Bruce S. Bochner, Amy D. Klion

Abstract

Background

Sialic acid–binding immunoglobulin-like lectin (Siglec)-8 is selectively expressed on eosinophils, mast cells and basophils, and, when engaged on eosinophils, can cause cell death.

Objective

To characterize surface and soluble Siglec-8 levels in normal (ND) and eosinophilic (EO) subjects and assess the efficacy of anti-Siglec-8 antibodies in inducing eosinophil cell death in vitro.

Methods

Eosinophil expression of Siglec-8 was assessed using flow cytometry and quantitative PCR. Serum soluble Siglec-8 levels were measured by ELISA. Induction of eosinophil death by IgG4 (c2E2 IgG4) and afucosylated IgG1 (c2E2 IgG1) anti-Siglec-8 antibodies was evaluated in vitro by flow cytometry and in vivo in humanized mice.

Results

Siglec-8 was consistently expressed on eosinophils from ND and EO and did not correlate with absolute eosinophil count (AEC) or disease activity. Soluble Siglec-8 levels were measurable in serum from most donors, unrelated to AEC or Siglec-8 surface expression. c2E2 IgG1 and c2E2 IgG4 were equally effective at inducing cell death (Annexin-V positivity) of purified eosinophils from ND and EO after overnight IL-5 priming. In contrast, killing of purified eosinophils without IL-5 was only seen in EO subjects, and NK-mediated eosinophil killing was seen only with c2E2 IgG1. Finally, treatment of humanized mice with anti-Siglec antibody led to robust depletion of IL-5-induced eosinophilia in vivo.

Conclusions

Siglec-8 is highly expressed on blood eosinophils from EO and ND and represents a potential therapeutic target for eosinophilic disorders. Enhanced killing of eosinophils in the presence of IL-5 may lead to increased efficacy in patients with IL-5-driven eosinophilia.

Graphical abstract

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Integrating the PILP-mineralization process into a restorative dental treatment

Publication date: Available online 10 December 2018

Source: Dental Materials

Author(s): Margot Bacino, Vishavjeet Girn, Hamid Nurrohman, Kuniko Saeki, Sally J Marshall, Laurie Gower, Ella Saeed, Ray Stewart, Thuan Le, Grayson W Marshall, Stefan Habelitz

Abstract

The addition of charged polymers, like poly-aspartic acid (pAsp), to mineralizing solutions allows for transport of calcium and phosphate ions into the lumen of collagen fibrils and subsequent crystallization of oriented apatite crystals by the so-called Polymer-Induced Liquid Precursor (PILP) mineralization process, leading to the functional recovery of artificial dentin lesions by intrafibrillar mineralization of collagen.

Objective

To evaluate the feasibility of applying the PILP method as part of a restorative treatment and test for effectiveness to functionally remineralize artificial lesions in dentin.

Materials and Methods

Two methods of providing pAsp to standardized artificial lesions during a restorative procedure were applied: (A) pAsp was mixed into commercial RMGI (resin modified glass ionomer) cement formulations and (B) pAsp was added at high concentration (25 mg/ml) in solution to rehydrate lesions before restoring with a RMGI cement. All specimens were immersed in simulated body fluid for two weeks to allow for remineralization and then analyzed for dehydration shrinkage, integrity of cement-dentin interface, degree of mineralization, and changes in the nanomechanical profile (E-modulus) across the lesion.

Results

After the remineralization treatment, lesion shrinkage was significantly reduced for all treatment groups compared to demineralized samples. Pores developed in RMGI when pAsp was added. A thin layer at the dentin-cement interface, rich in polymer formed possibly from a reaction between pAsp and the RMGI. When analyzed by SEM under vacuum, most lesions delaminated from the cement interface. EDS-analysis showed some but not full recovery of calcium and phosphorous levels for treatment groups that involved pAsp. Nanoindentations placed across the interface indicated improvement for RMGI containing 40% pAsp, and were significantly elevated when lesions were rehydrated with pAsp before being restored with RMGI. In particular the most demineralized outer zone recovered substantially in the elastic modulus, suggesting that functional remineralization has been initiated by pAsp delivery upon rehydration of air-dried demineralized dentin. In contrast, the effectiveness of the RMGI on functional remineralization of dentin was minimal when pAsp was absent.

Significance

Incorporation of pAsp into restorative treatments using RMGIs promises to be a feasible way to induce the PILP-mineralization process in a clinical setting and to repair the structure and properties of dentin damaged by the caries process.

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Biomimetic regulation of dentine remineralization by amino acid in vitro

Publication date: Available online 10 December 2018

Source: Dental Materials

Author(s): Yuanmei Zhang, Zhejun Wang, Tao Jiang, Yining Wang

Abstract

Objective

The aim of this study was to evaluate the effect of conditioning solutions containing DL-aspartic amino (Asp) on dentine remineralization induced by bioactive glass 45S5 (BAG) in a simulated oral environment.

Methods

Sixty dentine discs from human third molars were used. Dentine specimens were treated with ethylene diamine tetraacetic acid (EDTA) to create a partially demineralization model and randomly divided to 4 groups: Artificial saliva (AS) group, Asp group (pretreated with Asp and remineralized with distilled water), BAG group (pretreated with distilled water and remineralized by BAG), Asp-BAG group (pretreated with Asp and remineralized by BAG).

Each samples were measured at various time points, and at the end of the experiment, 6% citric acid challenge were taken. The remineralization characteristics were analyzed by using the spectroscopic data from attenuated total reflectance spectroscopy (ATR-IR) and Raman spectroscopy. The micro-morphology and structure were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Dentine permeability was measured before and after each treatment to evaluate the resistance of remineralized layer to acid and simulated oral environment.

Results

Both BAG and Asp-BAG groups significantly reduced dentine permeability and formed enamel-like apatite layers on dentine surface. For the mineralization of BAG, Asp showed inhibition effect. The 7-day mineral matrix area ratio in BAG group (12.54 ± 2.29) was lower than the value in the Asp-BAG group (17.77 ± 2.27) (p < 0.05) and the Raman intensity (RI%) in Asp-BAG Group (1.49 ± 0.26) was also significantly higher than that of BAG group (1.34 ± 0.14) (p < 0.05). According to permeability test, the apatite layer in BAG group and Asp-BAG group effectively occluded the dentinal tubules (p < 0.05) and had certain acidic resistance (p > 0.05). Furthermore, adsorbed acidic amino acid on hydroxyapatite (HAP) altered the crystal to increase into a larger size in diameter during crystal growth.

Significance

The study demonstrated that a superior remineralization efficacy of BAG with Asp pretreatment on dentine.

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Performance of Diffusion Kurtosis Imaging Versus Diffusion Tensor Imaging in Discriminating Between Benign Tissue, Low and High Gleason Grade Prostate Cancer

Publication date: Available online 11 December 2018

Source: Academic Radiology

Author(s): Maria Giovanna Di Trani, Marco Nezzo, Alessandra S. Caporale, Riccardo De Feo, Roberto Miano, Alessandro Mauriello, Pierluigi Bove, Guglielmo Manenti, Silvia Capuani

Rationale and Objectives

To investigate the performance of diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) in discriminating benign tissue, low- and high-grade prostate adenocarcinoma (PCa).

Materials and Methods

Forty-eight patients with biopsy-proven PCa of different Gleason grade (GG), who provided written informed consent, were enrolled. All subjects underwent 3T DWI examinations by using b values 0, 500, 1000, 1500, 2000, and 2500 s/mm² and six gradient directions. Mean diffusivity, fractional anisotropy (FA), apparent kurtosis (K), apparent kurtosis-derived diffusivity (D), and proxy fractional kurtosis anisotropy (KFA) maps were obtained. Regions of interest were selected in PCa, in the contralateral benign zone, and in the peritumoral area. Histogram analysis was performed by measuring mean, 10th, 25th, and 90th (p90) percentile of the whole-lesion volume. Kruskal–Wallis test with Bonferroni correction was used to assess significant differences between different regions of interest. The correlation between diffusion metrics and GG and between DKI and DTI parameters was evaluated with Pearson's test. ROC curve analysis was carried out to analyze the ability of histogram variables to differentiate low- and high-GG PCa.

Results

All metrics significantly discriminated PCa from benign and from peritumoral tissue (except for K, KFA_p90, and FA). K_p90 showed the highest correlation with GG and the best diagnostic ability (area under the curve = 0.84) in discriminating low- from high-risk PCa.

Conclusion

Compared to DTI, DKI provides complementary and additional information about prostate cancer tissue, resulting more sensitive to PCa-derived modifications and more accurate in discriminating low- and high-risk PCa.

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Calibrated Breast Density Measurements

Publication date: Available online 10 December 2018

Source: Academic Radiology

Author(s): Erin E. Fowler, Autumn Smallwood, Nadia Khan, Cassandra Miltich, Jennifer Drukteinis, Thomas A. Sellers, John Heine

Rationale and Objectives

Mammographic density is an important risk factor for breast cancer, but translation to the clinic requires assurance that prior work based on mammography is applicable to current technologies. The purpose of this work is to evaluate whether a calibration methodology developed previously produces breast density metrics predictive of breast cancer risk when applied to a case–control study.

Materials and Methods

A matched case control study (n = 319 pairs) was used to evaluate two calibrated measures of breast density. Two-dimensional mammograms were acquired from six Hologic mammography units: three conventional Selenia two-dimensional full-field digital mammography systems and three Dimensions digital breast tomosynthesis systems. We evaluated the capability of two calibrated breast density measures to quantify breast cancer risk: the mean (PG_m) and standard deviation (PG_sd) of the calibrated pixels. Matching variables included age, hormone replacement therapy usage/duration, screening history, and mammography unit. Calibrated measures were compared to the percentage of breast density (PD) determined with the operator-assisted Cumulus method. Conditional logistic regression was used to generate odds ratios (ORs) from continuous and quartile (Q) models with 95% confidence intervals. The area under the receiver operating characteristic curve (Az) was also used as a comparison metric. Both univariate models and models adjusted for body mass index and ethnicity were evaluated.

Results

In adjusted models, both PG_sd and PD were statistically significantly associated with breast cancer with similar Az of 0.61–0.62. The corresponding ORs and confidence intervals were also similar. For PG_sd, the OR was 1.34 (1.09, 1.66) for the continuous measure and 1.83 (1.11, 3.02), 2.19 (1.28, 3.73), and 2.20 (1.26, 3.85) for Q2–Q4. For PD, the OR was 1.43 (1.16, 1.76) for the continuous measure and 0.84 (0.52, 1.38), 1.96 (1.19, 3.23), and 2.27 (1.29, 4.00) for Q2–Q4. The results for PG_m were slightly attenuated and not statistically significant. The OR was 1.22 (0.99, 1.51) with Az = 0.60 for the continuous measure and 1.24 (0.78, 1.97), 0.98 (0.60, 1.61), and 1.26, (0.77, 2.07) for Q2–Q4 with Az = 0.60.

Conclusion

The calibrated PG_sd measure provided significant associations with breast cancer comparable to those given by PD. The calibrated PG_m performed slightly worse. These findings indicate that the calibration approach developed previously replicates under more general conditions.

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Influence of Inspiratory/Expiratory CT Registration on Quantitative Air Trapping

Publication date: Available online 10 December 2018

Source: Academic Radiology

Author(s): Oliver Weinheimer, Benjamin A. Hoff, Aleksa B. Fortuna, Antonio Fernández-Baldera, Philip Konietzke, Mark O. Wielpütz, Terry E. Robinson, Craig J. Galbán

Rationale and Objectives

The aim of this study was to assess variability in quantitative air trapping (QAT) measurements derived from spatially aligned expiration CT scans.

Materials and Methods

Sixty-four paired CT examinations, from 16 school-age cystic fibrosis subjects examined at four separate time intervals, were used in this study. For each pair, visually inspected lobe segmentation maps were generated and expiration CT data were registered to the inspiration CT frame. Measurements of QAT, the percentage of voxels on the expiration CT scan below a set threshold were calculated for each lobe and whole-lung from the registered expiration CT and compared to the true values from the unregistered data.

Results

A mathematical model, which simulates the effect of variable regions of lung deformation on QAT values calculated from aligned to those from unaligned data, showed the potential for large bias. Assessment of experimental QAT measurements using Bland-Altman plots corroborated the model simulations, demonstrating biases greater than 5% when QAT was approximately 40% of lung volume. These biases were removed when calculating QAT from aligned expiration CT data using the determinant of the Jacobian matrix. We found, by Dice coefficient analysis, good agreement between aligned expiration and inspiration segmentation maps for the whole-lung and all but one lobe (Dice coefficient > 0.9), with only the lingula generating a value below 0.9 (mean and standard deviation of 0.85 ± 0.06).

Conclusion

The subtle and predictable variability in corrected QAT observed in this study suggests that image registration is reliable in preserving the accuracy of the quantitative metrics.

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The strength of alpha and gamma oscillations predicts behavioral switch costs

Publication date: Available online 10 December 2018

Source: NeuroImage

Author(s): Amy L. Proskovec, Alex I. Wiesman, Tony W. Wilson

Abstract

Cognitive flexibility is often examined using task-switch paradigms, whereby individuals either switch between tasks or repeat the same task on successive trials. The behavioral costs of switching in terms of accuracy and reaction time are well-known, but the oscillatory dynamics underlying such costs are poorly understood. Herein, we examined 25 healthy adults who performed a task-switching paradigm during magnetoencephalography (MEG). All MEG data were transformed into the time-frequency domain and significant oscillatory responses were imaged separately per condition (i.e., switch, repeat) using a beamformer. To determine the impact of task switching on the neural dynamics, the resulting images were examined using paired-samples t-tests. Whole-brain correlations were also computed using the switch-related difference images (switch – repeat) and the switch-related behavioral data (i.e., switch costs). Our key results indicated stronger decreases in alpha and beta activity, and greater increases in gamma activity in nodes of the cingulo-opercular and fronto-parietal networks during switch relative to repeat trials. In addition, behavioral switch costs were positively correlated with switch-related differences in right frontal and inferior parietal alpha activity, and negatively correlated with switch effects in anterior cingulate and right temporoparietal gamma activity. In other words, participants who had a greater decrease in alpha or increase in gamma in these respective regions had smaller behavioral switch costs, which suggests that these oscillations are critical to supporting cognitive flexibility. In sum, we provide novel data linking switch effects and gamma oscillations, and employed a whole-brain approach to directly link switch-related oscillatory differences with switch-related performance differences.

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