Project description:Eosinophilic esophagitis (EoE) is a chronic inflammatory disorder characterized by upper gastrointestinal symptoms and the presence of high numbers of eosinophils in the esophagus. Although eosinophils in the esophagus have been found to be activated in subjects with EoE, detailed studies of intracellular signaling pathways involved in the mechanism of activation of eosinophils in EoE have heretofore been limited. The aim of the study was to assess whether any surface molecules or transcription factors are activated in peripheral eosinophils in subjects with EoE.Eosinophils and CD3+ lymphocytes were identified directly from 50 ?L of whole blood of EoE and control subjects. Using Hi-FACS, levels of surface activation markers, including CD66b, and intracellular phosphoepitopes, including phosphorylated forms of signal transducer and activator of transcription (phospho-STAT) 1 and 6, were measured within each cell subset.Levels of surface CD66b as well as levels of intracellular phospho-STAT1 and phospho-STAT6 in peripheral blood eosinophils were significantly higher for untreated subjects with EoE vs healthy controls (P < 0.05). Levels of phospho-STAT1 and phospho-STAT6 in peripheral blood eosinophils were lower in subjects with EoE on therapy versus untreated subjects with EoE (P < 0.05).Levels of phospho-STAT1 and phospho-STAT6, transcription factors involved in inflammatory processes, were both significantly higher in peripheral eosinophils from untreated (ie, newly diagnosed) subjects with EoE versus subjects with EoE on therapy, healthy controls. Blood-based measurements of CD66b and phospho-STAT levels in peripheral eosinophils may be beneficial for identifying EoE.
Project description:To review the understanding of the pathogenesis of eosinophilic esophagitis (EoE) and the role of the immune system in the disease process.Peer-reviewed articles on EoE from PubMed searching for "Eosinophilic Esophagitis and fibrosis" in the period of 1995 to 2013.Studies on the clinical and immunologic features, pathogenesis, and management of EoE.Recent work has revealed that thymic stromal lymphopoietin and basophil have an increased role in the pathogenesis of disease. Additional understanding on the role of fibrosis in EoE is emerging.The incidence of EoE is increasing like most atopic disease. Similar to other allergic diseases, EoE is treated with topical steroids and/or allergen avoidance.
Project description:Integrin ?IIb?3 is a highly abundant heterodimeric platelet receptor that can transmit information bidirectionally across the plasma membrane, and plays a critical role in hemostasis and thrombosis. Upon platelet activation, inside-out signaling pathways increase the affinity of ?IIb?3 for fibrinogen and other ligands. Ligand binding and integrin clustering subsequently stimulate outside-in signaling, which initiates and amplifies a range of cellular events driving essential platelet processes such as spreading, thrombus consolidation, and clot retraction. Integrin ?IIb?3 has served as an excellent model for the study of integrin biology, and it has become clear that integrin outside-in signaling is highly complex and involves a vast array of enzymes, signaling adaptors, and cytoskeletal components. In this review, we provide a concise but comprehensive overview of ?IIb?3 outside-in signaling, focusing on the key players involved, and how they cooperate to orchestrate this critical aspect of platelet biology. We also discuss gaps in the current understanding of ?IIb?3 outside-in signaling and highlight avenues for future investigation.
Project description:ObjectivesA minimally invasive biomarker to monitor disease activity is one of the greatest unmet clinical needs of the pediatric eosinophilic esophagitis (EoE) population. We aimed to determine whether circulating eosinophil progenitors (EoPs) could be used as a biomarker to identify pediatric patients with active EoE.MethodsIn a prospective observational study, peripheral blood samples, symptom history, and laboratory data were collected from pediatric patients undergoing endoscopy for evaluation of EoE on dietary therapy at Cincinnati Children's Hospital. Peripheral blood EoP level was determined by flow cytometry.ResultsThirty-four children with active (n = 16) and inactive (n = 18) EoE were included in the analysis. EoP levels in the peripheral blood were 3-fold higher in patients with active EoE than inactive EoE (P < 0.0025). Blood absolute eosinophil count did not distinguish between active and inactive EoE (P = 0.16). A cut-off EoP level ≥17 accurately detected active disease in 79% of patients with 94.4% specificity and 62.5% sensitivity (area under the curve 0.81; P < 0.0024). Antihistamine use lowered the threshold EoP level to detect active EoE.ConclusionsThis study suggests that blood EoP levels may be used as a biomarker to detect active EoE disease in patients undergoing food trials and potentially reduce the need for repeated endoscopies. Larger prospective studies are needed to investigate the effects of antihistamines and swallowed steroids on EoP mobilization into the peripheral blood and longitudinal studies to assess the performance of the assay in individual patients over time.
Project description:Integrins are transmembrane receptors that play important roles as modulators of cell behaviour through their adhesion properties and the initiation of signaling cascades. The ?IIb integrin subunit (CD41) is one of the first cell surface markers indicative of hematopoietic commitment. ?IIb pairs exclusively with ?3 to form the ?IIb?3 integrin. ?3 (CD61) also pairs with ?v (CD51) to form the ?v?3 integrin. The expression and putative role of these integrins during mouse hematopoietic development is as yet unknown. We show here that hematopoietic stem cells (HSCs) differentially express ?IIb?3 and ?v?3 integrins throughout development. Whereas the first HSCs generated in the aorta at mid-gestation express both integrins, HSCs from the placenta only express ?v?3, and most fetal liver HSCs do not express either integrin. By using ?IIb deficient embryos, we show that ?IIb is not only a reliable HSC marker but it also plays an important and specific function in maintaining the HSC activity in the mouse embryonic aorta.
Project description:Eosinophilic esophagitis is an emerging disease that is distinguished from gastroesophageal reflux disease by the expression of a unique esophageal transcriptome and the interplay of early life environmental factors with distinct genetic susceptibility elements at 5q22 (TSLP) and 2p23 (CAPN14). Rare genetic syndromes have uncovered the contribution of barrier disruption, mediated in part by defective desmosomes and dysregulated transforming growth factor beta production and signaling, to eosinophilic esophagitis pathophysiology. Experimental modeling has defined a cooperative role of activated eosinophils, mast cells, and the cytokines IL-5 and IL-13, mediated by allergic sensitization to multiple foods. Understanding these processes is opening the way to better treatment based on disrupting allergic inflammatory and type 2 cytokine-mediated responses, including anti-cytokine therapeutics and dietary therapy.
Project description:ImportanceEosinophilic esophagitis (EoE) is a chronic immune-mediated inflammatory disease of the esophagus that affects an estimated 34.4/100 000 people in Europe and North America. EoE affects both children and adults, and causes dysphagia, food impaction of the esophagus, and esophageal strictures.ObservationsEoE is defined by symptoms of esophageal dysfunction, such as vomiting, dysphagia, or feeding difficulties, in a patient with an esophageal biopsy demonstrating at least 15 eosinophils per high-power field in the absence of other conditions associated with esophageal eosinophilia such as gastroesophageal reflux disease or achalasia. Genetic factors and environmental factors, such as exposure to antibiotics early in life, are associated with EoE. Current therapies include proton pump inhibitors; topical steroid preparations, such as fluticasone and budesonide; dietary therapy with amino acid formula or empirical food elimination; and endoscopic dilation. In a systematic review of observational studies that included 1051 patients with EoE, proton pump inhibitor therapy was associated with a histologic response, defined as less than 15 eosinophils per high-power field on endoscopic biopsy, in 41.7% of patients, while placebo was associated with a 13.3% response rate. In a systematic review of 8 randomized trials of 437 patients with EoE, topical corticosteroid treatment was associated with histologic remission in 64.9% of patients compared with 13.3% for placebo. Patients with esophageal narrowing may require dilation. Objective assessment of therapeutic response typically requires endoscopy with biopsy.Conclusions and relevanceEoE has a prevalence of approximately 34.4/100 000 worldwide. Treatments consist of proton pump inhibitors, topical steroids, elemental diet, and empirical food elimination, with esophageal dilation reserved for patients with symptomatic esophageal narrowing.
Project description:BackgroundPatients with COVID-19 are at increased risk of thrombosis, which is associated with altered platelet function and coagulopathy, contributing to excess mortality.ObjectivesTo characterize the mechanism of altered platelet function in COVID-19 patients.MethodsThe platelet proteome, platelet functional responses, and platelet-neutrophil aggregates were compared between patients hospitalized with COVID-19 and healthy control subjects using tandem mass tag proteomic analysis, Western blotting, and flow cytometry.ResultsCOVID-19 patients showed a different profile of platelet protein expression (858 altered of the 5773 quantified). Levels of COVID-19 plasma markers were enhanced in the platelets of COVID-19 patients. Gene ontology pathway analysis demonstrated that the levels of granule secretory proteins were raised, whereas those of platelet activation proteins, such as the thrombopoietin receptor and protein kinase Cα, were lowered. Basally, platelets of COVID-19 patients showed enhanced phosphatidylserine exposure, with unaltered integrin αIIbβ3 activation and P-selectin expression. Agonist-stimulated integrin αIIbβ3 activation and phosphatidylserine exposure, but not P-selectin expression, were decreased in COVID-19 patients. COVID-19 patients had high levels of platelet-neutrophil aggregates, even under basal conditions, compared to controls. This association was disrupted by blocking P-selectin, demonstrating that platelet P-selectin is critical for the interaction.ConclusionsOverall, our data suggest the presence of 2 platelet populations in patients with COVID-19: one of circulating platelets with an altered proteome and reduced functional responses and another of P-selectin-expressing neutrophil-associated platelets. Platelet-driven thromboinflammation may therefore be one of the key factors enhancing the risk of thrombosis in COVID-19 patients.