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Chen X, Lin N, Li JM, Liu H, Abu-Romman A, Yaman E, Bian F, de Paiva CS, Pflugfelder SC, Li DQ. Ectoine, from a Natural Bacteria Protectant to a New Treatment of Dry Eye Disease. Pharmaceutics 2024; 16:236. [PMID: 38399289 PMCID: PMC10892505 DOI: 10.3390/pharmaceutics16020236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/26/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
Ectoine, a novel natural osmoprotectant, protects bacteria living in extreme environments. This study aimed to explore the therapeutic effect of ectoine for dry eye disease. An experimental dry eye model was created in C57BL/6 mice exposed to desiccating stress (DS) with untreated mice as controls (UT). DS mice were dosed topically with 0.5-2.0% of ectoine or a vehicle control. Corneal epithelial defects were detected via corneal smoothness and Oregon Green dextran (OGD) fluorescent staining. Pro-inflammatory cytokines and chemokines were evaluated using RT-qPCR and immunofluorescent staining. Compared with UT mice, corneal epithelial defects were observed as corneal smoothness irregularities and strong punctate OGD fluorescent staining in DS mice with vehicle. Ectoine treatment protected DS mice from corneal damage in a concentration-dependent manner, and ectoine at 1.0 and 2.0% significantly restored the corneal smoothness and reduced OGD staining to near normal levels. Expression of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) and chemokines CCL3 and CXCL11 was significantly elevated in the corneas and conjunctivas of DS mice, whereas 1.0 and 2.0% ectoine suppressed these inflammatory mediators to near normal levels. Our findings demonstrate that ectoine can significantly reduce the hallmark pathologies associated with dry eye and may be a promising candidate for treating human disease.
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Affiliation(s)
- Xin Chen
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA; (X.C.); (N.L.); (J.-M.L.); (A.A.-R.); (E.Y.); (F.B.); (C.S.d.P.); (S.C.P.)
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Na Lin
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA; (X.C.); (N.L.); (J.-M.L.); (A.A.-R.); (E.Y.); (F.B.); (C.S.d.P.); (S.C.P.)
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Jin-Miao Li
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA; (X.C.); (N.L.); (J.-M.L.); (A.A.-R.); (E.Y.); (F.B.); (C.S.d.P.); (S.C.P.)
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou 510060, China
| | - Haixia Liu
- Allergan, an AbbVie Company, Irvine, CA 92612, USA;
| | - Anmar Abu-Romman
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA; (X.C.); (N.L.); (J.-M.L.); (A.A.-R.); (E.Y.); (F.B.); (C.S.d.P.); (S.C.P.)
| | - Ebru Yaman
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA; (X.C.); (N.L.); (J.-M.L.); (A.A.-R.); (E.Y.); (F.B.); (C.S.d.P.); (S.C.P.)
| | - Fang Bian
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA; (X.C.); (N.L.); (J.-M.L.); (A.A.-R.); (E.Y.); (F.B.); (C.S.d.P.); (S.C.P.)
| | - Cintia S. de Paiva
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA; (X.C.); (N.L.); (J.-M.L.); (A.A.-R.); (E.Y.); (F.B.); (C.S.d.P.); (S.C.P.)
| | - Stephen C. Pflugfelder
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA; (X.C.); (N.L.); (J.-M.L.); (A.A.-R.); (E.Y.); (F.B.); (C.S.d.P.); (S.C.P.)
| | - De-Quan Li
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA; (X.C.); (N.L.); (J.-M.L.); (A.A.-R.); (E.Y.); (F.B.); (C.S.d.P.); (S.C.P.)
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Abusharha A, Pearce IE, Afsar T, Razak S. Evaluation of Therapeutic Capability of Emustil Drops against Tear Film Complications under Dry Environmental Conditions in Healthy Individuals. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:1298. [PMID: 37512109 PMCID: PMC10386218 DOI: 10.3390/medicina59071298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 06/23/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023]
Abstract
Background and Objectives: Dry eye disease (DED) is a multifactorial ailment of the tears and ocular surface. The purpose of this study was to assess the tear film physiology under controlled dry environmental conditions and compare the efficacy of oil-in-water emulsion drops on tear film parameters in protection and relief treatment modalities under low-humidity conditions. Emustil eye drops were used after exposure to a low-humidity environment in the relief method, whereas, in the protection method, the drops were applied before exposure to low humidity. Materials and Methods: 12 normal male subjects (mean age 34.0 ± 7.0 years) were exposed to ultra-dry environmental conditions. A number of tear film measurements were carried out under desiccating environmental conditions in a controlled environment chamber (CEC), where the chamber temperature sat at 21 °C with a relative humidity (RH) of 5%. Keeler's TearScope Plus and an HIRCAL grid were used to assess the tear break-up time and lipid layer thickness (LLT), and the evaporation rate was evaluated using a Servomed EP3 Evaporimeter. Results: LLT measurements showed that the dry environment affected LLT significantly (p = 0.031). The median grade of LLT dropped from grade 3 (50-70 nm) at 40% RH to grade 2 (13-50 nm) at 5% RH. A significant increase in LLT was seen after both modes of treatment, with a median LLT grade of 3 when the Emustil was used for both protection (p = 0.004) and relief (p = 0.016). The mean tear evaporation rate in normal environmental conditions (40%) was 40.46 ± 11.80 g/m2/h (0.11 µL/min) and increased sharply to 83.77 ± 20.37 g/m2/h (0.25 µL/min) after exposure to the dry environment. A minimal decrease in tear film evaporation rate was seen in relief; however, statistical tests showed that the decrease in tear film evaporation rate was not significant. Mean NITBUT dropped from 13.6 s at 40% RH to 6.6 s at 5% RH (p = 0.002). All NITBUT measurements at 5% RH (with or without the instillation of Emustil) were significantly lower than those at 40%. The instillation of Emustil at 5% RH resulted in a significant improvement in NITBUT for protection (p = 0.016) but this was not the case for relief (p = 0.0.56). Conclusions: A control environmental chamber (CEC) enables the analysis of tear film parameters comparable to those found in dry eye patients. This enables us to examine the capability of oil in emulsion drops to manage tear film disruption in healthy individuals. This study suggests that using Emustil oil-in-water emulsion before exposure to a dry environment should be advocated for people who work in dry environments.
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Affiliation(s)
- Ali Abusharha
- Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia
| | - Ian E Pearce
- Vision Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK
| | - Tayyaba Afsar
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia
| | - Suhail Razak
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia
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Rolando M, Merayo-Lloves J. Management Strategies for Evaporative Dry Eye Disease and Future Perspective. Curr Eye Res 2022; 47:813-823. [PMID: 35521685 DOI: 10.1080/02713683.2022.2039205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Dry eye disease (DED) is a common disorder that remains challenging from a clinical perspective. Unstable or deficient tear film is a major factor contributing to DED and the inability to resolve the loss of tear film homeostasis that accompanies DED can result in a vicious circle of inflammation and treatment-refractory disease. Recently recognized as a multifactorial disease, the main etiological subtypes of DED are aqueous-deficient and evaporative which exist on a continuum, although evaporative dry eye (EDE) is the more frequent classification. Although attaining greater recognition in recent years, there is currently no consensus and no clear recommendation on how to manage EDE. Clarity on the early diagnosis and treatment of EDE may facilitate the avoidance of progression to chronic inflammation, permanent damage to the ocular surface, and treatment-refractory disease. The purpose of this review was to identify current best practice for management of EDE in order to help clinicians in providing accurate diagnosis and optimized treatment. We summarize recent literature considering the role of the lipid layer on tear film stability, the importance of its composition and of its dynamic behavior, and the link between its malfunction and the insurgence and maintenance of tear film-related diseases. We have provided an assessment of the best management of lipid-deficient EDE based upon an understanding of disease pathophysiology, while indicating the flow of current treatments and possible future evolution of treatment approaches. Lipid containing eye drops may be considered as a step closer to natural tears from artificial aqueous tears because they more closely mimic the aqueous and lipid layers and may be used in combination with other management approaches. As a next step, we recommend working with a wider expert group to develop full guidelines to enable patient-centered management of EDE. Key pointsDry eye is a multifactorial disease of variable presentation with the tendency to become a chronic disease for which it is essential to identify and treat the main pathogenic mechanisms involved and tailor the treatment to the individual patient.Early intervention is needed to prevent the vicious cycle of DED and may require a multi-faceted management approach.EDE is not just a problem of MGD but can be the result of anything affecting blinking, mucin spreading, aqueous layer volume and content.Lipid-containing eye drops may provide significant relief of symptoms by improving the lipid layer and its spreading ability and, as such, are an appropriate component of the overall management of lipid-deficient EDE; natural lipid-containing eye drops should be the preferred treatment.
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Affiliation(s)
| | - Jesús Merayo-Lloves
- Instituto Universitario Fernández-Vega, Fundación de Investigación Oftalmológica & Universidad de Oviedo, Oviedo, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain
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Zhang R, Pandzic E, Park M, Wakefield D, Di Girolamo N. Inducing dry eye disease using a custom engineered desiccation system: Impact on the ocular surface including keratin-14-positive limbal epithelial stem cells. Ocul Surf 2021; 21:145-159. [PMID: 33930539 DOI: 10.1016/j.jtos.2021.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/14/2021] [Accepted: 04/18/2021] [Indexed: 12/20/2022]
Abstract
PURPOSE Dry eye disease (DED) is characterized by loss of tear film stability that becomes self-sustaining in a vicious cycle of pathophysiological events. Currently, desiccation stress (DS) is the dominant procedure for inducing DED in mice, however its' effect on limbal epithelial stem cells (LESCs) has been overlooked. This study aimed to establish a DS model via the use of a novel hardware to investigate the impact on the ocular surface including LESCs. METHODS A mouse transporter unit was customized to generate a dehumidified environment. C57BL/6J mice were exposed to mild DS and injected with scopolamine hydrobromide (SH) or remained untreated (UT) under standard vivarium conditions for 10 consecutive days (n = 28/group). Clinical assessments included phenol red tear-thread test, fluorescein staining and optical coherence tomography assessments. Histopathological and immunofluorescence was used to evaluate tissue architecture, goblet cell (GC) status, lacrimal gland (LG) inflammation and epithelial phenotype on the ocular surface. Whole flat-mounted corneas were immunostained for keratin-14 (K14), then imaged by confocal microscopy and analyzed computationally to investigate the effect of DS on LESCs. RESULTS Custom modifications made to the animal transporter unit resulted in dehumidified cage relative humidity (RH) of 43.5 ± 4.79% compared to the vivarium 53.9 ± 1.8% (p = 0.0243). Under these conditions, aqueous tear production in mice was suppressed whilst corneal permeability and corneal irregularity significantly increased. H&E staining indicated stressed corneal basal epithelial cells and increased desquamation. DS-exposed mice had reduced GC density (41.0 ± 5.10 GC/mm vs 46.9 ± 3.88 GC/mm, p = 0.0482) and LGs from these mice exhibited elevated CD4+ cell infiltration compared to controls. DS elicited K14+ epithelial cell displacement, as indicated by increased fluorescence signal at a distance of 50-100 μm radially inwards from the limbus [0.63 ± 0.053% (DS) vs 0.54 ± 0.060% (UT), p = 0.0317]. CONCLUSIONS Application of mild DS using customized hardware and SH injections generated features of DED in mice. Following DS, ocular surface epithelial cell health decreased and LESCs appeared stressed. This suggested that potential downstream effects of DS on corneal homeostasis are present, a phenomenon that is currently under-investigated. The method used to induce DED in this study enables the development of a chronic model which more closely resembles disease seen in the clinic.
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Affiliation(s)
- Richard Zhang
- Mechanisms of Disease and Translational Research, School of Medical Sciences, Faculty of Medicine, University of NSW, Sydney, NSW, 2052, Australia
| | - Elvis Pandzic
- Biomedical Imaging Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Mijeong Park
- Mechanisms of Disease and Translational Research, School of Medical Sciences, Faculty of Medicine, University of NSW, Sydney, NSW, 2052, Australia
| | - Denis Wakefield
- Mechanisms of Disease and Translational Research, School of Medical Sciences, Faculty of Medicine, University of NSW, Sydney, NSW, 2052, Australia
| | - Nick Di Girolamo
- Mechanisms of Disease and Translational Research, School of Medical Sciences, Faculty of Medicine, University of NSW, Sydney, NSW, 2052, Australia.
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Formulation Considerations for the Management of Dry Eye Disease. Pharmaceutics 2021; 13:pharmaceutics13020207. [PMID: 33546193 PMCID: PMC7913303 DOI: 10.3390/pharmaceutics13020207] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 01/27/2021] [Accepted: 01/29/2021] [Indexed: 11/25/2022] Open
Abstract
Dry eye disease (DED) is one of the most common ocular surface disorders characterised by a deficiency in quality and/or quantity of the tear fluid. Due to its multifactorial nature involving several inter-related underlying pathologies, it can rapidly accelerate to become a chronic refractory condition. Therefore, several therapeutic interventions are often simultaneously recommended to manage DED efficiently. Typically, artificial tear supplements are the first line of treatment, followed by topical application of medicated eyedrops. However, the bioavailability of topical eyedrops is generally low as the well-developed protective mechanisms of the eye ensure their rapid clearance from the precorneal space, thus limiting ocular penetration of the incorporated drug. Moreover, excipients commonly used in eyedrops can potentially exhibit ocular toxicity and further exacerbate the signs and symptoms of DED. Therefore, formulation development of topical eyedrops is rather challenging. This review highlights the challenges typically faced in eyedrop development, in particular, those intended for the management of DED. Firstly, various artificial tear supplements currently on the market, their mechanisms of action, as well as their application, are discussed. Furthermore, formulation strategies generally used to enhance ocular drug delivery, their advantages and limitations, as well as their application in commercially available DED eyedrops are described.
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Garrigue JS, Amrane M, Faure MO, Holopainen JM, Tong L. Relevance of Lipid-Based Products in the Management of Dry Eye Disease. J Ocul Pharmacol Ther 2017; 33:647-661. [PMID: 28956698 PMCID: PMC5655476 DOI: 10.1089/jop.2017.0052] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 08/15/2017] [Indexed: 12/23/2022] Open
Abstract
Components of the ocular surface synergistically contribute to maintaining and protecting a smooth refractive layer to facilitate the optimal transmission of light. At the air-water interface, the tear film lipid layer (TFLL), a mixture of lipids and proteins, plays a key role in tear surface tension and is important for the physiological hydration of the ocular surface and for ocular homeostasis. Alterations in tear fluid rheology, differences in lipid composition, or downregulation of specific tear proteins are found in most types of ocular surface disease, including dry eye disease (DED). Artificial tears have long been a first line of treatment in DED and aim to replace or supplement tears. More recently, lipid-containing eye drops have been developed to more closely mimic the combination of aqueous and lipid layers of the TFLL. Over the last 2 decades, our understanding of the nature and importance of lipids in the tear film in health and disease has increased substantially. The aim of this article is to provide a brief overview of our current understanding of tear film properties and review the effectiveness of lipid-based products in the treatment of DED. Liposome lid sprays, emulsion eye drops, and other lipid-containing formulations are discussed.
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Affiliation(s)
| | | | | | - Juha M. Holopainen
- Helsinki Eye Lab, Ophthalmology, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Louis Tong
- Singapore Eye Research Institute, Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Duke-NUS Medical School, Singapore
- Singapore National Eye Center, Singapore
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Xiao W, Sun L, Zhang N, Ye W. Adverse Effect Profile of Topical Ocular Administration of Fingolimod for Treatment of Dry Eye Disease. Basic Clin Pharmacol Toxicol 2016; 120:398-406. [PMID: 27888572 DOI: 10.1111/bcpt.12717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 11/02/2016] [Indexed: 12/01/2022]
Abstract
Fingolimod is a promising prodrug in attenuating multiple sclerosis and prolonging survival of organ allograft, with many other protective effects. Its mechanism of action is related to the internalization of sphingosine 1-phosphate receptors (S1PRs). Our previous study indicated that fingolimod eyedrops was efficacious in inhibiting ocular inflammation in a dry eye disease (DED) model of non-obese diabetic (NOD) mice. In the current study, we evaluated potential adverse effects of fingolimod eyedrops. Inbred 10-week-old BALB/c mice were randomly divided into four groups, fingolimod-treated groups at three different concentrations (0.01%, 0.1% and 0.5%) and a negative control group without intervention. Our results showed that in the 0.5% fingolimod group, adverse effects such as photophobia, catacleisis and corneal oedema were observed after 1 week of treatment. 1 month later, corneal opacity, oedema and neovascularization persisted till the mice were killed 2 months later. In contrast, there was no significant abnormality in the negative control group, and 0.01% and 0.1% fingolimod-treated groups. During a 2-month treatment period, we did not detect fingolimod, nor significant change in blood cells in peripheral blood, nor pathological changes in retina and systemic organs. Combined with our previous study and the current results, we recommend that an optimal range of safe and effective concentration of fingolimod as eyedrops is between 0.005% and 0.1%.
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Affiliation(s)
- Weibao Xiao
- Department of Ophthalmology, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Li Sun
- Department of Ophthalmology, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Nan Zhang
- Department of Ophthalmology, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Wen Ye
- Department of Ophthalmology, Huashan Hospital Affiliated to Fudan University, Shanghai, China
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Choi JH, Kim JH, Li Z, Oh HJ, Ahn KY, Yoon KC. Efficacy of the mineral oil and hyaluronic acid mixture eye drops in murine dry eye. KOREAN JOURNAL OF OPHTHALMOLOGY 2015; 29:131-7. [PMID: 25829831 PMCID: PMC4369516 DOI: 10.3341/kjo.2015.29.2.131] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 01/24/2014] [Indexed: 11/25/2022] Open
Abstract
Purpose To investigate the therapeutic effects of mineral oil (MO) and hyaluronic acid (HA) mixture eye drops on the tear film and ocular surface in a mouse model of experimental dry eye (EDE). Methods Eye drops consisting of 0.1% HA alone or mixed with 0.1%, 0.5%, or 5.0% MO were applied to desiccating stress-induced murine dry eyes. Tear volume, corneal irregularity score, tear film break-up time (TBUT), and corneal fluorescein staining scores were measured at 5 and 10 days after treatment. Ten days after treatment, goblet cells in the conjunctiva were counted after Periodic acid-Schiff staining. Results There was no significant difference in the tear volume between desiccating stress-induced groups. The corneal irregularity score was lower in the 0.5% MO group compared with the EDE and HA groups. The 0.5% and 5.0% MO groups showed a significant improvement in TBUT compared with the EDE group. Mice treated with 0.1% and 0.5% MO mixture eye drops showed a significant improvement in fluorescein staining scores compared with the EDE group and the HA group. The conjunctival goblet cell count was higher in the 0.5% MO group compared with the EDE group and HA group. Conclusions The MO and HA mixture eye drops had a beneficial effect on the tear films and ocular surface of murine dry eye. The application of 0.5% MO and 0.1% HA mixture eye drops could improve corneal irregularity, the corneal fluorescein staining score, and conjunctival goblet cell count compared with 0.1% HA eye drops in the treatment of EDE.
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Affiliation(s)
- Jung Han Choi
- Department of Ophthalmology and Research Institute of Medical Sciences, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea
| | - Jung Han Kim
- Department of Ophthalmology and Research Institute of Medical Sciences, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea. ; Kim's Eye Clinic of the 21st Century, Seoul, Korea
| | - Zhengri Li
- Department of Ophthalmology and Research Institute of Medical Sciences, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea
| | - Han Jin Oh
- Department of Ophthalmology and Research Institute of Medical Sciences, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea
| | - Kyu Youn Ahn
- Department of Anatomy, Chonnam National University Medical School, Gwangju, Korea
| | - Kyung Chul Yoon
- Department of Ophthalmology and Research Institute of Medical Sciences, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea
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Kossler AL, Wang J, Feuer W, Tse DT. Neurostimulation of the lacrimal nerve for enhanced tear production. Ophthalmic Plast Reconstr Surg 2015; 31:145-51. [PMID: 25126767 PMCID: PMC4329098 DOI: 10.1097/iop.0000000000000234] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To design a proof-of-concept study to assess the effect of lacrimal nerve stimulation (LNS) with an implantable pulse generator (IPG) to increase aqueous tear production. METHODS Experimental animal study design of 6 Dutch Belted rabbits. Ultra high-resolution optical coherence tomography (UHR-OCT) quantified tear production by measuring the baseline tear volume of each rabbit's OD and OS. A neurostimulator was implanted adjacent to the right lacrimal nerve. After 2 minutes of LNS (100 μs, 1.6 mA, 20 Hz, 5-8 V), the tear volumes were measured with UHR-OCT. The change in tear volume was quantified and compared with the nonstimulated OS. Three rabbits underwent chronic LNS (100 μs, 1.6 mA, 10 Hz, 2 V) and their lacrimal glands were harvested for histopathologic analysis. RESULTS The UHR-OCT imaging of the OD tear volume showed a 441% average increase in tear production after LNS as a percent of baseline. After stimulation, OD had statistically significant greater increase in tear volumes than OS (p = 0.028, Wilcoxon test). Poststimulation OD tear volumes were significantly greater compared with baseline (p = 0.028, Wilcoxon test). Histopathologic examination of the lacrimal glands showed no discernible tissue damage from chronic neurostimulation. In addition, there were no gross adverse effects on the general well-being of the animals due to chronic stimulation. CONCLUSIONS LNS with an IPG appears to increase aqueous tear production. Chronic LNS showed no histopathologic lacrimal gland damage. This study suggests that LNS is a promising new treatment strategy to increase aqueous tear production.
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Affiliation(s)
| | - Jianhua Wang
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine
| | - William Feuer
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine
| | - David T. Tse
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine
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Kam WR, Sullivan DA. Neurotransmitter influence on human meibomian gland epithelial cells. Invest Ophthalmol Vis Sci 2011; 52:8543-8. [PMID: 21969302 DOI: 10.1167/iovs.11-8113] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE A striking characteristic of the human meibomian gland is its rich sensory, sympathetic, and parasympathetic innervation, yet the functional relevance of these nerve fibers remains unknown. Acting on the hypothesis that neurotransmitters are released in the vicinity of the gland, act on glandular receptors, and influence the production, secretion, and/or delivery of meibomian gland secretions to the ocular surface, the goal in this study was to begin to determine whether neurotransmitters influence the meibomian gland. METHODS Immortalized human meibomian gland epithelial (SLHMG) cells were examined for the presence of vasoactive intestinal peptide (VIP) and muscarinic acetylcholine (mACh) receptor transcripts and proteins. Cells were also exposed to VIP, carbachol, forskolin, and/or 3-isobutyl-1-methylxanthine (IBMX) to determine whether these agents, alone or in combination, modulate the adenylyl cyclase pathway, the accumulation of intracellular free calcium ([Ca2+]i), or cell proliferation. RESULTS Results demonstrate that SLHMG cells transcribe and translate VIP and mACh receptors; VIP, with either IBMX or forskolin, activates the adenylyl cyclase pathway, and the effect of VIP and forskolin together is synergistic; both VIP and carbachol increase intracellular [Ca2+] in SLHMG cells; and VIP with forskolin stimulates SLHMG cell proliferation. CONCLUSIONS This study shows that parasympathetic neurotransmitters and their agonists influence the function of human meibomian gland epithelial cells. It remains to be determined whether this action alters the production, secretion, and/or delivery of meibum to the ocular surface.
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Affiliation(s)
- Wendy R Kam
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts 02114, USA
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Wei Y, Epstein SP, Fukuoka S, Birmingham NP, Li XM, Asbell PA. sPLA2-IIa amplifies ocular surface inflammation in the experimental dry eye (DE) BALB/c mouse model. Invest Ophthalmol Vis Sci 2011; 52:4780-8. [PMID: 21519031 DOI: 10.1167/iovs.10-6350] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE sPLA2-IIa is a biomarker for many inflammatory diseases in humans and is found at high levels in human tears. However, its role in ocular surface inflammation remains unclear. An experimentally induced BALB/c mouse dry eye (DE) model was used to elucidate the role of sPLA2-IIa in ocular surface inflammation. METHODS BALB/c mice were subcutaneously injected with scopolamine and placed in a daytime air-drying device for 5 to 10 days. Control mice received no treatment. DE status was evaluated with tear production with a phenol-red thread method. Tear inflammatory cytokines were quantified by multiplex immunoassays. Ocular surface inflammation and sPLA2-IIa expression were examined by immune-staining and quantitative (q)RT(2)-PCR. Conjunctiva (CNJ) of the mice was cultured for prostaglandin E2 production induced by sPLA2-IIa with various amount of sPLA2-IIa inhibitor, S-3319. RESULTS Treated mice produced fewer tears and heavier corneal (CN) fluorescein staining than the untreated controls (P < 0.001). They also revealed lower goblet cell density (P < 0.001) with greater inflammatory cell infiltration within the conjunctiva, and higher concentration of tear inflammatory cytokines than the controls. Moreover, treated mice showed heavier sPLA2-IIa immune staining than the controls in the CNJ epithelium, but not in the CN epithelium or the lacrimal gland. Treated mice exhibited upregulated sPLA2-IIa and cytokine gene transcription. Furthermore, CNJ cultures treated with sPLA2-IIa inhibitor showed significantly reduced sPLA2-IIa-induced inflammation. CONCLUSIONS This is the first report regarding sPLA2-IIa in the regulation of ocular surface inflammation. The findings may therefore lead to new therapeutic strategies for ocular surface inflammation, such as DE disease.
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Affiliation(s)
- Yi Wei
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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