Characterization of Siglec-8 Expression on Lavage Cells after Segmental Lung Allergen Challenge.

BACKGROUND: Siglec-8 is present at a high level on human blood eosinophils and low level on blood basophils. Engagement of Siglec-8 on blood eosinophils causes its internalization and results in death. Siglec-8 is a potential therapeutic target in eosinophilic asthma. OBJECTIVES: The aim of this study was to determine Siglec-8 levels on eosinophils and basophils recruited during lung inflammation. METHOD: We analyzed surface Siglec-8 by flow cytometry on cells obtained by bronchoalveolar lavage (BAL) 48 h after segmental lung allergen challenge of human subjects with mild allergic asthma and used confocal microscopy to compare Siglec-8 distribution on BAL and blood eosinophils. RESULTS: Like their blood counterparts, BAL eosinophils had high unimodal surface Siglec-8, while BAL basophils had lower but detectable surface Siglec-8. BAL macrophages, monocytes, neutrophils, and plasmacytoid dendritic cells did not express surface Siglec-8. Microscopy of freshly isolated blood eosinophils demonstrated homogeneous Siglec-8 distribution over the cell surface. Upon incubation with IL-5, Siglec-8 on the surface of eosinophils became localized in patches both at the nucleopod tip and at the opposite cell pole. BAL eosinophils also had a patchy Siglec-8 distribution. CONCLUSIONS: We conclude that 48 h after segmental allergen challenge, overall levels of Siglec-8 expression on airway eosinophils resemble those on blood eosinophils, but with a patchier distribution, a pattern consistent with activation. Thus, therapeutic targeting of Siglec-8 has the potential to impact blood as well as lung eosinophils, which may be associated with an improved outcome in eosinophilic lung diseases.

Characteristics and outcomes of interventions for pediatric laryngomalacia: A systematic review with meta-analysis.

OBJECTIVES: To analyze characteristics of children treated for laryngomalacia to determine predictive factors and provide an updated meta-analysis on outcomes. METHODS: A systematic review was conducted according to PRISMA guidelines from inception to May 2, 2023, using CINAHL, PubMed, and Scopus databases. Study screening, data extraction, quality rating, and risk of bias assessment were performed by 2 independent reviewers. Data were meta-analyzed using fixed-/random-effects model to derive continuous measures (mean), proportions (%), and mean difference (Δ) with 95% confidence interval (CI). RESULTS: 100 articles were identified with information on outcomes of pediatric patients with laryngomalacia (N = 18,317). The mean age was 10.6 months (range: 0 to 252, 95%CI: 9.6 to 11.6, p = 0.00) with a 1.4:1 male to female ratio. Many patients presented with stridor (87.9%, 95% CI: 69.8 to 98.4), and the most common comorbidity at time of diagnosis was gastroesophageal reflux disease (48.8%, 95%CI: 40.9 to 56.8). Based on the patient population included in our analysis, 86.1% received supraglottoplasty (95% CI: 78.7 to 92.1). A total of 73.6% (95% CI: 65.5 to 81.0) had reported complete resolution of symptoms. For patients with a concurrent diagnosis of sleep disordered breathing receiving supraglottoplasty, the apnea-hypopnea index improved with a mean difference of -10.0 (95%CI: 15.6 to -4.5) events per hour post-treatment. CONCLUSIONS: Laryngomalacia continues to be a common problem in the pediatric population. Supraglottoplasty remains an effective treatment option leading to symptomatic improvement in many cases. For those with concurrent sleep disordered breathing, supraglottoplasty lowers the apnea-hypopnea index.

Surgical sponge blood salvage spinning device design and testing.

One method to clear intraoperative blood from the surgical field is to remove blood with surgical sponges. Currently, absorbed blood cannot be retrieved effectively and is lost. A spinning device was created to salvage red blood cells from the sponges. With this device the sponges are gently washed with saline and the resultant bloody fluid can be delivered to a cell saver to prepare it for autologous blood transfusion. In this article, we demonstrate how a novel sponge extractor can be used to extract blood from sponges. Several tests were conducted with porcine blood to optimise viable blood salvage by varying spin speed, and spin time of the device. At spin speeds greater than 1000 RPM, the blood salvaged from the device was similar to blood volumes obtained by hand wringing sponges. Cell viability testing yielded no significant differences in haemolysis for device trials compared to gently hand wringing. Spin time testing showed no significant differences in the blood salvaged at times greater than one minute. Optimal parameters for the device were determined to be a one-minute spin time at 1500 RPM.

Control of cytokine-driven eosinophil migratory behavior by TGF-beta-induced protein (TGFBI) and periostin.

Periostin, which is induced by interleukin (IL)-13, is an extracellular matrix (ECM) protein that supports αMß2 integrin-mediated adhesion and migration of IL-5-stimulated eosinophils. Transforming growth factor (TGF)-ß-induced protein (TGFBI) is a widely expressed periostin paralog known to support monocyte adhesion. Our objective was to compare eosinophil adhesion and migration on TGFBI and periostin in the presence of IL-5-family cytokines. Eosinophil adhesion after 1 h and random motility over 20 h in the presence of various concentrations of IL-5, IL-3, or granulocyte macrophage-colony stimulating factor (GM-CSF) were quantified in wells coated with various concentrations of TGFBI or periostin. Results were compared to video microscopy of eosinophils. Cytokine-stimulated eosinophils adhered equivalently well to TGFBI or periostin in a coating concentration-dependent manner. Adhesion was blocked by anti-αMß2 and stimulated at the lowest concentration by GM-CSF. In the motility assay, periostin was more potent than TGFBI, the coating-concentration effect was bimodal, and IL-3 was the most potent cytokine. Video microscopy revealed that under the optimal coating condition of 5 µg/ml periostin, most eosinophils migrated persistently and were polarized and acorn-shaped with a ruffling forward edge and granules gathered together, in front of the nucleus. On 10 µg/ml periostin or TGFBI, more eosinophils adopted a flattened pancake morphology with dispersed granules and nuclear lobes, and slower migration. Conversion between acorn and pancake morphologies were observed. We conclude that TGFBI or periostin supports two modes of migration by IL-5 family cytokine-activated eosinophils. The rapid mode is favored by intermediate protein coatings and the slower by higher coating concentrations. We speculate that eosinophils move by haptotaxis up a gradient of adhesive ECM protein and then slow down to surveil the tissue.