Dr. Barney is an Associate Professor in the Department of Ophthalmology and Visual Sciences at the University of Wisconsin School of Medicine and Public Health. His clinical training is in all aspects of ocular immunology including uveitis and inflammatory disease of the anterior segment of the eye. His laboratory interests include the cellular signaling events on the ocular surface undergoing allergic reactions. He is a Principle Investigator on NIH funded research.
Use of Topical Insulin to Treat Refractory Neurotrophic Corneal Ulcers
Cornea. 2017 Nov;36(11):1426-1428. doi: 10.1097/ICO.0000000000001297.
PURPOSE: To report the clinical course of 6 patients with refractory neurotrophic corneal ulcers that were treated with topical insulin drops.
METHODS: Retrospective chart review of patients who had neurotrophic corneal ulcers or epithelial defects refractory to standard medical and surgical treatment. Insulin drops, prepared by mixing regular insulin in artificial tears with a polyethylene glycol and propylene glycol base at a concentration of 1 unit per milliliter, were prescribed 2 to 3 times daily.
RESULTS: Six patients, aged 2 to 73 years, developed neurotrophic corneal ulcers refractory to a range of medical and surgical treatments, including bandage contact lens, amniotic membrane grafting, and permanent tarsorrhaphy. Each patient was administered topical insulin drops with complete corneal reepithelialization within 7 to 25 days.
CONCLUSIONS: Topical insulin may be a simple and effective treatment for refractory neurotrophic corneal ulcers. Further study is required to determine the clinical efficacy and side effect profile of insulin drops.
Safety and efficacy of autologous serum eye drop for treatment of dry eyes in graft-versus-host disease
Cutan Ocul Toxicol. 2017 Jun;36(2):152-156. doi: 10.1080/15569527.2016.1209770. Epub 2016 Jul 22.
PURPOSE: To evaluate the treatment of autologous serum eye drops (ASED) on dry eyes in patients with graft-versus-host disease (GVHD).
METHODS: A retrospective chart review of 35 patients with a history of ocular GVHD following hematopoietic stem cell transplantation that used ASED to alleviate dry eye symptoms was performed. Patients were categorized into three different groups. If patients had available ophthalmic data before and after starting treatment was group 1 (n = 14), had available ophthalmic data after starting treatment in group 2 (n = 10) and had available ophthalmic data before treatment or did not have any data after starting treatment in group 3 (n = 11). Data were collected on patient's age, gender, primary diagnosis, visual acuity and fluorescein corneal staining were collected on individual eyes in order to evaluate the efficacy of the ASED on alleviating dry eye-related signs and symptoms.
RESULTS: No adverse ocular effect from the ASED was found in our series (except one fungal keratitis). All patients reported either improvement (55%) or stability (45%) in their ocular symptoms upon the use of ASED. In patients with available data before and after starting treatment, the corneal staining score improved by a median of 1 (p = 0.003) and the LogMAR visual acuity had a non-significant improvement.
CONCLUSION: In our study, ASED used by patients with ocular GVHD were both safe and effective. ASED should be considered in patients with GVHD who suffer from dry eyes.
Rheumatoid arthritis and the prevalence of diabetic retinopathy
Rheumatology (Oxford). 2015 Aug;54(8):1415-9. doi: 10.1093/rheumatology/kev012. Epub 2015 Mar 2.
OBJECTIVE: RA increases vascular disease and angiogenesis, yet a 1964 Lancet report paradoxically linked RA to lower diabetic retinopathy. Our objective was to examine RA as a risk factor for diabetic retinopathy compared with other vascular risk factors.
METHODS: This cohort study compared the prevalence of diabetic retinopathy in diabetes patients with and without RA in a 5% Medicare sample. We analysed the impact of RA on the prevalence of diabetic retinopathy using multivariate logistic regression calculating adjusted rate ratios (ARRs) controlling for sociodemographics, co-morbidity and health utilization. Sensitivity analysis examined eye exam rates.
RESULTS: Among 256 331 Medicare diabetes patients, 5572 (2%) had RA. Diabetic retinopathy was less prevalent in patients with RA compared with those without RA (13.7% vs 16.1%, P ≤ 0.01). Compared with patients without RA, the adjusted model demonstrated that patients with diabetes and RA were 28% less likely to have diabetic retinopathy and 4% more likely to receive an eye exam [ARR 0.72 (95% CI 0.67, 0.77), ARR 1.04 (95% CI 1.02, 1.06)].
CONCLUSION: Findings support the 1964 paradox observing decreased diabetic retinopathy in patients with RA. These findings pose new questions regarding whether RA physiology or treatments protect against diabetic retinopathy and how intraocular factors vary in contrast to adverse vascular changes elsewhere.
Poly(ethylene glycol) hydrogels with adaptable mechanical and degradation properties for use in biomedical applications
Macromol Biosci. 2014 May;14(5):687-98. doi: 10.1002/mabi.201300418. Epub 2014 Jan 25.
Requirements of hydrogels for drug delivery, wound dressings, and surgical implantation can be extensive, including suitable mechanical properties and tailorable degradation time frames. Herein, an adaptable PEG-based hydrogel, whose mechanical properties and degradation rate can be systematically adjusted to meet these criteria by altering simple variables such as the PEG molecular weight, is described. The performance of these hydrogels in three physical manipulations (pushing, pulling, and folding), representative of manipulations that they may undergo during typical biomedical use, is also assessed. While not all of these formulations can withstand these manipulations, a subset did, and it is intended to further optimize these formulations for specific clinical applications. Additionally, the outcomes of the physical manipulation tests indicate that simply having a high modulus does not correlate with biomedical applicability.
Conjunctivitis: a systematic review of diagnosis and treatment
JAMA. 2013 Oct 23;310(16):1721-9. doi: 10.1001/jama.2013.280318.
IMPORTANCE: Conjunctivitis is a common problem.
OBJECTIVE: To examine the diagnosis, management, and treatment of conjunctivitis, including various antibiotics and alternatives to antibiotic use in infectious conjunctivitis and use of antihistamines and mast cell stabilizers in allergic conjunctivitis.
EVIDENCE REVIEW: A search of the literature published through March 2013, using PubMed, the ISI Web of Knowledge database, and the Cochrane Library was performed. Eligible articles were selected after review of titles, abstracts, and references.
FINDINGS: Viral conjunctivitis is the most common overall cause of infectious conjunctivitis and usually does not require treatment; the signs and symptoms at presentation are variable. Bacterial conjunctivitis is the second most common cause of infectious conjunctivitis, with most uncomplicated cases resolving in 1 to 2 weeks. Mattering and adherence of the eyelids on waking, lack of itching, and absence of a history of conjunctivitis are the strongest factors associated with bacterial conjunctivitis. Topical antibiotics decrease the duration of bacterial conjunctivitis and allow earlier return to school or work. Conjunctivitis secondary to sexually transmitted diseases such as chlamydia and gonorrhea requires systemic treatment in addition to topical antibiotic therapy. Allergic conjunctivitis is encountered in up to 40% of the population, but only a small proportion of these individuals seek medical help; itching is the most consistent sign in allergic conjunctivitis, and treatment consists of topical antihistamines and mast cell inhibitors.
CONCLUSIONS AND RELEVANCE: The majority of cases in bacterial conjunctivitis are self-limiting and no treatment is necessary in uncomplicated cases. However, conjunctivitis caused by gonorrhea or chlamydia and conjunctivitis in contact lens wearers should be treated with antibiotics. Treatment for viral conjunctivitis is supportive. Treatment with antihistamines and mast cell stabilizers alleviates the symptoms of allergic conjunctivitis.
Regulation of the receptor for TNFalpha, TNFR1, in human conjunctival epithelial cells
Invest Ophthalmol Vis Sci. 2008 Sep;49(9):3992-8. doi: 10.1167/iovs.08-1873. Epub 2008 May 16.
PURPOSE: Previous studies demonstrated that mast cell-derived TNFalpha stimulation is critical to the upregulation of intercellular adhesion molecule (ICAM)-1 on human conjunctival epithelial cells (HCECs), which is an important feature of ocular allergic inflammation. Shedding of TNFR1 by TNFalpha-converting enzyme (TACE) is a primary mechanism for the regulation of TNFalpha-mediated events. This process has not been examined in HCECs. In this study, the authors examined the regulation of TNFR1 expression and shedding by TACE on primary HCECs and the IOBA-NHC conjunctival epithelial cell line.
METHODS: Primary human conjunctival mast cells and epithelial cells were obtained from cadaveric conjunctival tissue. HCECs were incubated with and without activators (IgE-activated mast cell supernates, phorbol myristate acetate [PMA; to activate TACE], TNFalpha, and IFNgamma [to upregulate TNFR1]) for 24 hours. Pretreatment with the TACE inhibitor TAPI-2 was used to inhibit shedding of TNFR1. Supernates collected from the incubations were analyzed with ELISA for soluble TNFR1 (sTNFR1). With the use of flow cytometry, cells were harvested from these experiments for analysis of TNFR1 and ICAM-1 receptor expression.
RESULTS: IgE-activated conjunctival mast cell supernates upregulated the expression of TNFR1. TAPI-2 inhibited the PMA-induced release of sTNFR1 receptor and enhanced the surface expression of TNFR1 in HCECs in a dose-dependent manner. Upregulation of TNFR1 expression by priming with TAPI-2 and IFNgamma resulted in enhanced ICAM-1 expression in response to TNFalpha stimulation (significant change in the slope of the dose-response curve).
CONCLUSIONS: These results demonstrate that TACE promotes TNFR1 shedding in HCECs and that TNFR1 expression may be a more significant target than TNFalpha for intervention in ocular inflammation.
Allergic tears promote upregulation of eosinophil adhesion to conjunctival epithelial cells in an ex vivo model: inhibition with olopatadine treatment
Invest Ophthalmol Vis Sci. 2006 Aug;47(8):3423-9. doi: 10.1167/iovs.06-0088.
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.
Toll-like receptor 2 expression on human conjunctival epithelial cells: a pathway for Staphylococcus aureus involvement in chronic ocular proinflammatory responses
Ann Allergy Asthma Immunol. 2005 Apr;94(4):486-97. doi: 10.1016/S1081-1206(10)61120-9.
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.
Ocular allergic disease
Curr Opin Allergy Clin Immunol. 2004 Oct;4(5):455-9. doi: 10.1097/00130832-200410000-00020.
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.
The promotion of eosinophil degranulation and adhesion to conjunctival epithelial cells by IgE-activated conjunctival mast cells
Ann Allergy Asthma Immunol. 2004 Jan;92(1):65-72. doi: 10.1016/S1081-1206(10)61712-7.
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.
Differential and cooperative effects of TNFalpha, IL-1beta, and IFNgamma on human conjunctival epithelial cell receptor expression and chemokine release
Invest Ophthalmol Vis Sci. 2003 May;44(5):2010-5. doi: 10.1167/iovs.02-0721.
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.
Pathophysiology of ocular allergy: the roles of conjunctival mast cells and epithelial cells
Curr Allergy Asthma Rep. 2002 Jul;2(4):332-9. doi: 10.1007/s11882-002-0062-6.
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.