Biomedical subjects

James L Stahl

Publications and source records attributed to James L Stahl.

6 recordsLinked to original sources

PubMed2006

Allergic tears promote upregulation of eosinophil adhesion to conjunctival epithelial cells in an ex vivo model: inhibition with olopatadine treatment.

PURPOSE: The mechanism by which eosinophils adhere to the ocular surface during allergic inflammation is unknown. This study examined whether the incubation of human conjunctival epithelial cells (HCEs) with tears from allergic subjects promotes eosinophil adhesion, and it examined the effect of treatment with olopatadine on this process. METHODS: Allergic subjects (n = 6) and nonallergic subjects (n = 4) were treated in season for 1 week with olopatadine in one eye while the other eye remained untreated. Tears were collected from both eyes with the use of a microcapillary tube. HCEs were acquired by enzymatic digestion of cadaveric conjunctival tissues. Confluent cultures of HCEs were treated with diluted tears for 24 hours before incubation with peripheral blood eosinophils (purified with negative magnetic bead selection). Eosinophil adhesion was measured with an eosinophil peroxidase assay. RESULTS: Incubation of HCEs with tears from allergic subjects significantly upregulated eosinophil adhesion compared with eosinophil adhesion to untreated HCEs or with HCEs treated with nonallergic tears and untreated HCEs (P < 0.05). Eosinophil adhesion to HCEs treated with tears from olopatadine-treated allergic subjects was inhibited (P < 0.01) compared with tear-stimulated adhesion observed from untreated eyes. Percentage of inhibition was 43.3% +/- 13.9% (mean +/- SD). Blocking antibodies demonstrated that eosinophil adhesion to HCEs in vitro involved beta2 integrins on eosinophils but not intercellular adhesion molecule-1 on human HCEs. CONCLUSIONS: Tears collected from allergic subjects contain bioactivity capable of upregulating eosinophil adhesion to HCEs in vitro. Inhibition of this process by treatment of subjects with olopatadine suggests that some of the cellular targets of this drug may play a role in promoting eosinophil adhesion.

Adult↗

PubMed2005

Toll-like receptor 2 expression on human conjunctival epithelial cells: a pathway for Staphylococcus aureus involvement in chronic ocular proinflammatory responses.

BACKGROUND: Staphylococcus aureus colonization is common in atopic keratoconjunctivitis, potentially activating epithelial cells via toll-like receptor 2 (TLR-2) and the receptor for platelet-activating factor (PAFR). OBJECTIVES: To examine human conjunctival epithelial cells for the expression of TLR-2 in vitro and in vivo and to evaluate the role of TLR-2 in S aureus-mediated activation of these cells. METHODS: Conjunctival epithelial cells isolated from cadaveric tissues were stimulated with interferon gamma (IFN-gamma) or a commercial S aureus cell wall extract (Staphylococcus aureus-CWE) (with or without anti-TLR-2 blocking antibody or PAFR antagonist) and were analyzed for tumor necrosis factor alpha (TNF-alpha) and interleukin 8 (IL-8) release; surface expression of TLR-2, intercellular adhesion molecule-1, HLA, and CD14; and TLR-2 messenger RNA expression. Ocular surface cells collected via impression cytology were examined for TLR-2 expression via flow cytometry. RESULTS: Expression of TLR-2 was up-regulated on conjunctival epithelial cells by IFN-gamma and Staphylococcus aureus-CWE. Expression of TLR-2 messenger RNA was increased by IFN-gamma. Staphylococcus aureus-CWE up-regulated intercellular adhesion molecule 1, HLA, and CD14 expression and increased TNF-alpha and IL-8 release in a dose-dependent manner. Anti-TLR-2 significantly inhibited TNF-alpha release, whereas PAFR antagonist significantly inhibited IL-8 release. Toll-like receptor 2 was expressed on conjunctival epithelial cells from 4 of 5 patients with atopic keratoconjunctivitis, 3 of 5 with seasonal allergies, and 0 of 3 without allergies. CONCLUSIONS: Conjunctival epithelial cells express TLR-2 and may play an active role in the chronic ocular inflammatory response to S aureus through pathways that involve TLR-2 and PAFR.

Adolescent↗

PubMed2004

The promotion of eosinophil degranulation and adhesion to conjunctival epithelial cells by IgE-activated conjunctival mast cells.

BACKGROUND: Allergen-mediated mast cell activation is a key feature of ocular allergic diseases. Evidence of eosinophil-derived mediators in tears and conjunctival biopsy specimens has been associated with chronic ocular allergic inflammation. OBJECTIVE: To examine the role of conjunctival mast cell mediators in eosinophil adhesion to conjunctival epithelial cells and eosinophil degranulation. METHODS: Conjunctival cells were obtained by enzymatic digestion of cadaveric conjunctival tissues. Eosinophils were obtained from peripheral blood samples using negative magnetic bead selection. The effect of IgE-activated mast cell supernates on eosinophil degranulation and adherence to epithelial cells was compared with supernates obtained from mast cells pretreated with a degranulation inhibitor (olopatadine). Eosinophil adhesion was measured by eosinophil peroxidase assay, and eosinophil degranulation was measured by eosinophil-derived neurotoxin radioimmunoassay. RESULTS: IgE-activated conjunctival mast cell supernates stimulated adhesion of eosinophils to epithelial cells (20.4% +/- 6.3% vs 3.1% +/- 1.0%; P = .048). Degranulation was not required for this process (no effect of olopatadine). IgE-activated mast cell supernates stimulated eosinophil-derived neurotoxin release (108.89 +/- 8.27 ng/10(6) cells vs 79.45 +/- 5.21 ng/10(6) cells for controls, P = .02), which was significantly inhibited by pretreatment of mast cells with a degranulation inhibitor (79.22 +/- 4.33 ng/10(6) cells vs 61.09 +/- 5.39 ng/10(6) cells for olopatadine pretreated and untreated, respectively, P = .02). CONCLUSIONS: Mediators released from conjunctival mast cells promote eosinophil adhesion to conjunctival epithelial cells and eosinophil degranulation. Degranulation inhibition studies suggest that different mast cell mediators are involved in regulation of these events.

Adolescent↗

PubMed2004

Ocular allergic disease.

PURPOSE OF REVIEW: This review will focus on recent advances in our understanding of the pathogenesis of allergic eye diseases. Common findings in acute allergic conjunctivitis (seasonal and perennial) and chronic allergic conjunctivitis (vernal keratoconjunctivitis, atopic keratoconjunctivitis, and giant papillary conjunctivitis) include evidence of mast cell activation and eosinophil attraction and activation. Cytokine levels found in tears, conjunctival impression cytology and biopsy specimens, and serum have been evaluated as markers of disease, and as targets of therapeutic intervention. RECENT FINDINGS: Human conjunctival epithelial cells respond to tumor necrosis factor alpha, interleukin-1 beta, and interferon-gamma individually and in combination. Intracellular adhesion molecule-1 expression is upregulated by interleukin-1 beta and tumor necrosis factor alpha. Conjunctival epithelial cells release interleukin-8 in response to interleukin-1 beta and tumor necrosis factor alpha but not interferon-gamma. Supernatants from activated mast cells cause increased adhesion of eosinophils to conjunctival epithelium. Tear levels of tumor necrosis factor alpha were elevated in vernal keratoconjunctivitis patients compared with normal controls. T cell lines from chronic allergic eye disease patients showed inconsistent production of cytokines in atopic and vernal keratoconjunctivitis and low levels in giant papillary conjunctivitis. Vernal keratoconjunctivitis patients have differing levels of eosinophil cationic protein in their serum if they were serum specific immunoglobulin E positive compared to serum specific immunoglobulin E negative patients. SUMMARY: Recent findings continue to expand our basic knowledge of mechanisms and differences between seasonal and perennial allergic conjunctivitis and atopic and vernal keratoconjunctivitis. Understanding the complex interactions and cross talk between cells, cytokines and other mediators is relevant for new therapeutic approaches directed at specific disease entities.

Conjunctivitis, Allergic↗

PubMed2003

Differential and cooperative effects of TNFalpha, IL-1beta, and IFNgamma on human conjunctival epithelial cell receptor expression and chemokine release.

PURPOSE: To gain better understanding of conjunctival epithelial cell responses to proinflammatory cytokines, the individual and combined effects of TNFalpha, IL-1beta, and IFNgamma on chemokine release (IL-8, regulated on activation normal T-cell expressed and secreted [RANTES]) and surface receptor expression (intercellular adhesion molecule [ICAM]-1, and HLA-DR, -DP, and -DQ) were examined. METHODS: Conjunctival epithelial cells were isolated from cadaveric conjunctival tissues and cultured in 24-well plates until almost confluent. Recombinant cytokines (0.005-50 ng/mL) were added, alone or in various combinations, 24 hours before harvesting of supernates for ELISAs and cells for flow cytometry. RESULTS: TNFalpha, IL-1beta, and IFNgamma had distinctive individual and combined effects on the parameters tested. Although TNFalpha and IL-1beta had similar and synergistic effects on increasing expression of ICAM-1, IL-1beta was a more potent upregulator of the release of IL-8 than was TNFalpha. Upregulation of IL-8 was additive when IL-1beta was combined with TNFalpha. Neither TNFalpha nor IL-1beta increased expression of HLA. In contrast, IFNgamma was a potent upregulator of both surface receptors (ICAM-1 and HLA) but IFNgamma alone had no effect on mediator release (IL-8 and RANTES). Release of RANTES required two cytokine signals, with IFNgamma and TNFalpha being the most potent combination. CONCLUSIONS: Knowledge of the differential and combined effects of proinflammatory cytokines on conjunctival epithelial cells allows better understanding of ocular inflammation.

Cell Separation↗

PubMed2002

Pathophysiology of ocular allergy: the roles of conjunctival mast cells and epithelial cells.

Allergic eye disease is associated with IgE-mediated conjunctival inflammation leading to signs of immediate hypersensitivity, including redness, itching, and tearing. Pathologic studies using conjunctival mast cells demonstrate that these cells, when sensitized with IgE antibody and exposed to environmental allergens, release mediators involved with allergic inflammation. The type, release kinetics, and concentration of these mediators in the conjunctiva have not been completely characterized. The ability to isolate and purify mast cells and epithelial cells from human conjunctival tissue has permitted the study of mediator release and cell-to-cell signaling in this tissue. Our laboratory has developed in vitro and in vivo models to better understand how inflammatory cells are recruited to and infiltrate conjunctival tissues. These models demonstrate that mast-cell activation may supply sufficient cytokine signaling to initiate and direct the well-orchestrated trafficking of eosinophils to the ocular surface, facilitate their adhesion, and cause release of potent mediators of ocular inflammation.

Conjunctiva↗