Toxicity of eosinophil cationic proteins for guinea pig tracheal epithelium in vitro.
ABSTRACT We tested the effects of four eosinophil granule cationic proteins: major basic protein (MBP), eosinophil cationic protein (ECP), eosinophil peroxidase (EPO), and eosinophil-derived neurotoxin (EDN), on guinea pig tracheal epithelium in vitro. Examination by inverted microscopy revealed that MBP, both the form stabilized by alkylation of sulfhydryl groups as well as the native form of the molecule, ECP, EPO by itself, as well as EPO + H2O2 + halide, but not EDN, cause dose-related damage to the tracheal epithelium. The lowest concentrations of MBP and ECP causing damage were 10 and 100 micrograms/ml, respectively. In contrast, EDN, although biochemically similar to ECP, did not damage the tracheal epithelium in concentrations of up to 200 micrograms/ml. MBP caused exfoliation, as well as bleb formation and ciliostasis. EPO in the presence of the H2O2-producing enzyme glucose oxidase (GO), Cl-, 0.11 M, and iodide caused ciliostasis, bleb formation, and exfoliation of epithelial cells at concentrations as low as 1 U/ml (3.9 micrograms/ml). EPO + GO in the presence of Cl-, 0.11 M, alone or with Cl- and l-, 10(-4) M, or Cl- and Br-, 5 x 10(-5) M, were all toxic to epithelium. Surprisingly, EPO by itself caused partial ciliostasis, bleb formation, and exfoliation of epithelial cells in a dose-related manner at concentrations as low as 10 to 30 U/ml (39 to 121 micrograms/ml). These results confirm prior observations showing the toxicity of MBP to tracheal epithelium and indicate that ECP and EPO alone, as well as EPO + GO + halide, cause damage. Thus, several eosinophil granule proteins are able to damage respiratory epithelium.
- SourceAvailable from: Glenn T Furuta[Show abstract] [Hide abstract]
ABSTRACT: Over the last decade, treatment plans for eosinophilic esophagitis included the use of elemental formula, elimination diets, systemic corticosteroids, and the gavage of aerosolized steroids. Except for one placebo-controlled blinded prospective study, most decision making has been based on retrospective or uncontrolled studies and clinical experience. In this article, three authors from diverse backgrounds combine their resources to propose treatment paths with justification based on their clinical experience and interpretation of the literature.Gastrointestinal Endoscopy Clinics of North America 02/2008; 18(1):195-217; xi. DOI:10.1016/j.giec.2007.09.003
- [Show abstract] [Hide abstract]
ABSTRACT: Chronic rhinosinusitis (CRS) is a chronic disease that affects 14.2% of the US adult population. Despite being widespread, little is known about the etiology of CRS. Treatment has been symptomatic and focused on relieving symptoms. Recent investigations into causes of CRS have revealed that most CRS patients have an eosinophilic infiltration of their nasal tissue (mucosa), regardless of atopy and elevated immunoglobulin E levels. Although fungi are ubiquitous and in the nasal mucus of both healthy people and patients, it is only in the patients that the eosinophils (part of the inflammatory response) are found. Fungi in the nasal mucus are harmless, yet in CRS patients these same fungi stimulate an inflammatory response, inducing the eosinophils to leave the blood vessels and enter the nasal and sinus tissue and ultimately enter the nasal airway mucus. In the nasal mucus these eosinophils attack the fungi and destroy the fungi by the release of a toxic substance called major basic protein (MBP) from the granules in the eosinophils. This degranulation and release of the toxic MBP not only destroys fungi, but also produces collateral damage injuring the nasal and sinus mucosal lining tissue. The injury to the mucosal lining makes the nasal and sinus mucosa susceptible to penetration and potential infection by bacteria. When this tissue inflammation and damage is persistent and prolonged we call it CRS. The diagnosis of CRS is based largely on symptomatic criteria, with anterior rhinoscopy or endoscopy, and, if there is any doubt about the diagnosis, computed tomography imaging is employed to confirm the presence of diseased sinus mucosa. Treatment of CRS, whether medical (intranasal corticosteroids, saline irrigations) or surgical, is aimed at decreasing inflammation and obstruction in the sinonasal passages. Antibiotics, although commonly used in CRS, should not be administered unless there is suspicion of an acute bacterial infection. The theory behind the fungal and eosinophilic etiology of CRS has led to use of an antifungal compound, intranasal Amphotericin B. In clinical studies, topical irrigation with Amphotericin B has been shown to be both a safe and effective treatment for CRS.Therapeutics and Clinical Risk Management 07/2007; 3(2):319-25. DOI:10.2147/tcrm.2007.3.2.319 · 1.34 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: The effects of platelet-activating factor (PAF) and IL-5 on intracellular pH were investigated in human eosinophils. Purified peripheral blood eosinophils were loaded with the ratiometric fluorescent pH indicator BCECF-AM ester. Stimulation of eosinophils with PAF produced time-dependent alkalinization of the cytoplasm from an initial pH of 7.1+/-0.04 to 7.5+/-0.05. A similar alkalinization response was produced by the calcium ionophore, ionomycin and by the calcium ATPase inhibitor, thapsigargin. These compounds as well as PAF produce significant increases in cytoplasmic calcium ([Ca2+]i). In contrast, IL-5 and the protein kinase C (PKC) activator phorbol myristate acetate (PMA) did not produce cytoplasmic alkalinization and had no effect on [Ca2+]i in eosinophils. PAF-stimulated alkalinization was not inhibited under conditions that blocked plasma membrane Na+-H+ exchange, proton channel or plasma membrane H+-ATPase activities. Measurements of intragranule pH with a cell permeant pH indicator (LysoSensor Yellow/Blue DND-160), which partitions into intracellular acidic compartments, revealed that PAF-stimulated cytosolic alkalinization correlated with intragranule acidification. These results suggest that the increase in [Ca2+]i after PAF stimulation activates a H+-ATPase present in the granule membranes, leading to enhanced granule acidification and cytoplasmic alkalinization. We propose that granule acidification is an important step in solubilization of major basic protein crystals, which are stored within the granule core, in preparation for degranulation and release of these proteins.Journal of Cell Science 12/2004; 117(Pt 24):5749-57. DOI:10.1242/jcs.01498 · 5.33 Impact Factor