1
|
Nguyen A, Naidoo KK, Ajouz L, Xu X, Zhao C, Robinson MR, Borchman D. Changes in Human Meibum Lipid Composition Related to the Presence and Severity of Meibomian Gland Dysfunction. J Ocul Pharmacol Ther 2024. [PMID: 39150383 DOI: 10.1089/jop.2024.0063] [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: 08/17/2024] Open
Abstract
Purpose: Changes in meibum composition and quantity in meibomian gland dysfunction (MGD) result in tear film instability and dry eye. This exploratory study aimed to identify changes in (O-acyl)-ω-hydroxy fatty acid (OAHFA) and hydrocarbon chain (HC) unsaturation levels in meibum related to the presence and severity of MGD. Methods: Meibum samples were collected from 3 cohorts of adults with no MGD, mild-to-moderate MGD, and severe MGD in a noninterventional clinical trial (NCT01979887). OAHFAs, cholesterol esters (CE), HC unsaturation, and HC length in the meibum samples were quantified with 1H-nuclear magnetic resonance spectroscopy using 2 methods of normalization. Results: Meibum samples from 62 subjects were analyzed: 21 non-MGD, 21 mild-to-moderate MGD, and 20 severe MGD. Meibum OAHFA and CE levels and HC unsaturation were reduced with increasing severity of MGD, with most pairwise comparisons significant (P < 0.05, t-tests), following the order non-MGD > mild-to-moderate MGD > severe MGD. Regardless of the resonances used for normalization, each pairwise comparison of OAHFA, CE, and HC unsaturation levels in MGD (combined severities) versus non-MGD samples was significant (P < 0.01, t-test). Analysis using various normalization equations showed reductions of 20%-22% for OAHFAs, 51%-57% for CE, and 36%-66% for HC unsaturation in MGD (combined severities) compared with non-MGD. HC length was not altered in MGD (combined severities) compared with non-MGD samples (t-test). Conclusions: Meibum OAHFA, CE, and HC unsaturation levels were reduced in MGD and were lowest in the severe MGD cohort. These findings may contribute to the understanding of the pathophysiology of MGD.
Collapse
Affiliation(s)
- Ashley Nguyen
- Allergan, an AbbVie company, Irvine, California, USA
| | - Kugen K Naidoo
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, USA
| | - Layla Ajouz
- Allergan, an AbbVie company, Irvine, California, USA
| | - Xiaoming Xu
- Allergan, an AbbVie company, Irvine, California, USA
| | - Cathy Zhao
- Allergan, an AbbVie company, Irvine, California, USA
| | | | - Douglas Borchman
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, USA
| |
Collapse
|
2
|
Shi MD, Sung KC, Huang JM, Chen CH, Wang YJ. Development of an Ex Vivo Porcine Eye Model for Exploring the Pathogenicity of Acanthamoeba. Microorganisms 2024; 12:1161. [PMID: 38930543 PMCID: PMC11206127 DOI: 10.3390/microorganisms12061161] [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: 05/22/2024] [Revised: 06/05/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024] Open
Abstract
Acanthamoeba, a widely distributed free-living amoeba found in various environments, is an opportunistic pathogen responsible for causing Acanthamoeba keratitis, a condition that may lead to blindness. However, identifying the pathogenicity of Acanthamoeba is challenging due to its complex life cycle, ability to adapt to different environments, variable virulence factors, and intricate interactions with the host immune system. Additionally, the development of an effective model for studying Acanthamoeba pathogenicity is limited, hindering a comprehensive understanding of the mechanisms underlying its virulence and host interactions. The aim of this study was to develop an ex vivo model for Acanthamoeba infection using porcine eyeballs and to evaluate the pathogenicity of the Acanthamoeba isolates. Based on slit lamp and biopsy analysis, the developed ex vivo model is capable of successfully infecting Acanthamoeba within 3 days. Histopathological staining revealed that clinical isolates of Acanthamoeba exhibited greater corneal stroma destruction and invasion in this model than environmental isolates. Our results highlight the importance of an ex vivo porcine eye model in elucidating the pathogenesis of Acanthamoeba infection and its potential implications for understanding and managing Acanthamoeba-related ocular diseases.
Collapse
Affiliation(s)
- Ming-Der Shi
- Department of Clinical Laboratory, Chest Hospital, Ministry of Health and Welfare, Tainan 717, Taiwan; (M.-D.S.); (K.-C.S.)
| | - Ko-Chiang Sung
- Department of Clinical Laboratory, Chest Hospital, Ministry of Health and Welfare, Tainan 717, Taiwan; (M.-D.S.); (K.-C.S.)
| | - Jian-Ming Huang
- School of Medicine, National Tsing Hua University, Hsinchu 300, Taiwan;
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Chun-Hsien Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan;
| | - Yu-Jen Wang
- Department of Parasitology, School of Medicine, China Medical University, Taichung 404, Taiwan
| |
Collapse
|
3
|
Stubb H, Viitaja T, Trevorah RM, Raitanen JE, Moilanen J, Svedström KJ, Ekholm FS. Another Brick in the Wall of Tear Film Insights Added Through the Total Synthesis and Biophysical Profiling of anteiso-Branched Wax and Cholesteryl Esters. JOURNAL OF NATURAL PRODUCTS 2024; 87:954-965. [PMID: 38547477 DOI: 10.1021/acs.jnatprod.3c01247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
The tear film lipid layer (TFLL) plays a vital part in maintenance of ocular health and represents a unique biological barrier comprising unusual and specialized lipid classes and species. The wax and cholesteryl esters (WEs and CEs) constitute roughly 80-90% of the TFLL. The majority of species in these lipid classes are branched and it is therefore surprising that the synthesis and properties of the second largest category of species, i.e., the anteiso-branched species, remain poorly characterized. In this study, we have developed a total synthesis route and completed a detailed NMR spectroscopic characterization of two common anteiso-branched species, namely: (22S)-22-methyltetracosanyl oleate and cholesteryl (22'S)-22'-methyltetracosanoate. In addition, we have studied their structural properties in the bulk state by wide-angle and small-angle X-ray scattering and their behavior at the aqueous interface using Langmuir monolayer techniques. A comparison to the properties displayed by iso-branched and straight-chain analogues indicate that branching patterns lead to distinct properties in the CE and WE lipid classes. Overall, this study complements the previous work in the field and adds another important brick in the tear film insights wall.
Collapse
Affiliation(s)
- Henrik Stubb
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Tuomo Viitaja
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
- Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, FI-00290 Helsinki, Finland
| | - Ryan M Trevorah
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Jan-Erik Raitanen
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Jukka Moilanen
- Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, FI-00290 Helsinki, Finland
| | - Kirsi J Svedström
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Filip S Ekholm
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| |
Collapse
|
4
|
Wood PL, Le A, Palazzolo DL. Comparative Lipidomics of Oral Commensal and Opportunistic Bacteria. Metabolites 2024; 14:240. [PMID: 38668368 PMCID: PMC11052126 DOI: 10.3390/metabo14040240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/15/2024] [Accepted: 04/19/2024] [Indexed: 04/28/2024] Open
Abstract
The oral cavity contains a vast array of microbes that contribute to the balance between oral health and disease. In addition, oral bacteria can gain access to the circulation and contribute to other diseases and chronic conditions. There are a limited number of publications available regarding the comparative lipidomics of oral bacteria and fungi involved in the construction of oral biofilms, hence our decision to study the lipidomics of representative oral bacteria and a fungus. We performed high-resolution mass spectrometric analyses (<2.0 ppm mass error) of the lipidomes from five Gram-positive commensal bacteria: Streptococcus oralis, Streptococcus intermedius, Streptococcus mitis, Streptococcus sanguinis, and Streptococcus gordonii; five Gram-positive opportunistic bacteria: Streptococcus mutans, Staphylococcus epidermis, Streptococcus acidominimus, Actinomyces viscosus, and Nanosynbacter lyticus; seven Gram-negative opportunistic bacteria: Porphyromonas gingivalis. Prevotella brevis, Proteus vulgaris, Fusobacterium nucleatum, Veillonella parvula, Treponema denticola, and Alkermansia muciniphila; and one fungus: Candida albicans. Our mass spectrometric analytical platform allowed for a detailed evaluation of the many structural modifications made by microbes for the three major lipid scaffolds: glycerol, sphingosine and fatty acyls of hydroxy fatty acids (FAHFAs).
Collapse
Affiliation(s)
- Paul L. Wood
- Metabolomics Unit, College of Veterinary Medicine, Lincoln Memorial University, 6965 Cumberland Gap Pkwy., Harrogate, TN 37752, USA
| | - Annie Le
- Clinical Training Program, DeBusk College of Osteopathic Medicine, Lincoln Memorial University, 6965 Cumberland Gap Pkwy., Harrogate, TN 37752, USA
| | - Dominic L. Palazzolo
- Department of Physiology, DeBusk College of Osteopathic Medicine, Lincoln Memorial University, 6965 Cumberland Gap Pkwy., Harrogate, TN 37752, USA;
| |
Collapse
|
5
|
Ponzini E. Tear biomarkers. Adv Clin Chem 2024; 120:69-115. [PMID: 38762243 DOI: 10.1016/bs.acc.2024.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2024]
Abstract
An extensive exploration of lacrimal fluid molecular biomarkers in understanding and diagnosing a spectrum of ocular and systemic diseases is presented. The chapter provides an overview of lacrimal fluid composition, elucidating the roles of proteins, lipids, metabolites, and nucleic acids within the tear film. Pooled versus single-tear analysis is discussed to underline the benefits and challenges associated with both approaches, offering insights into optimal strategies for tear sample analysis. Subsequently, an in-depth analysis of tear collection methods is presented, with a focus on Schirmer's test strips and microcapillary tubes methods. Alternative tear collection techniques are also explored, shedding light on their applicability and advantages. Variability factors, including age, sex, and diurnal fluctuations, are examined in the context of their impact on tear biomarker analysis. The main body of the chapter is dedicated to discussing specific biomarkers associated with ocular discomfort and a wide array of ocular diseases. From dry eye disease and thyroid-associated ophthalmopathy to keratoconus, age-related macular degeneration, diabetic retinopathy, and glaucoma, the intricate relationship between molecular biomarkers and these conditions is thoroughly dissected. Expanding beyond ocular pathologies, the chapter explores the applicability of tear biomarkers in diagnosing systemic diseases such as multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, Parkinson's disease, and cancer. This broader perspective underscores the potential of lacrimal fluid analysis in offering non-invasive diagnostic tools for conditions with far-reaching implications.
Collapse
Affiliation(s)
- Erika Ponzini
- Department of Materials Science, University of Milano Bicocca, Milan, Italy; COMiB Research Center, University of Milano Bicocca, Milan, Italy.
| |
Collapse
|
6
|
Trevorah RM, Viljanen M, Viitaja T, Stubb H, Sevón J, Konovalov O, Jankowski M, Fontaine P, Hemmerle A, Raitanen JE, Ekholm FS, Svedström KJ. New Insights into the Molecular Structure of Tear Film Lipids Revealed by Surface X-ray Scattering. J Phys Chem Lett 2024; 15:316-322. [PMID: 38170161 PMCID: PMC10788950 DOI: 10.1021/acs.jpclett.3c02958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/12/2023] [Accepted: 12/28/2023] [Indexed: 01/05/2024]
Abstract
The tear film lipid layer (TFLL) is a unique biological membrane that serves a pivotal role in the maintenance of ocular surface health. Reaching an overarching understanding of the functional principle of the TFLL has been hampered by a lack of insights into the structural and functional roles played by individual lipid classes. To bridge this knowledge gap, we herein focus on studying films formed by principal lipid classes by surface scattering methods. Through grazing incidence X-ray diffraction and X-ray reflectivity studies, we reveal quantitative data about the lattice distances, molecular tilt angles, and mono/multilayer thickness and density profiles for central TFLL lipid classes under close to simulated physiological conditions. In addition, we discuss the correlation of the results to those obtained previously with the natural lipid composition of meibum.
Collapse
Affiliation(s)
- Ryan M. Trevorah
- Department
of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Mira Viljanen
- Department
of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Tuomo Viitaja
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
- Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, FI-00290 Helsinki, Finland
| | - Henrik Stubb
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Julia Sevón
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Oleg Konovalov
- The
European Synchrotron Radiation Facility - ESRF, 71 Avenue des Martyrs, CS 40220, Grenoble Cedex 9 38043, France
| | - Maciej Jankowski
- The
European Synchrotron Radiation Facility - ESRF, 71 Avenue des Martyrs, CS 40220, Grenoble Cedex 9 38043, France
| | - Philippe Fontaine
- Synchrotron
SOLEIL, L’Orme des Merisiers, Départementale 128, 91190 Saint-Aubin, France
| | - Arnaud Hemmerle
- Synchrotron
SOLEIL, L’Orme des Merisiers, Départementale 128, 91190 Saint-Aubin, France
| | - Jan-Erik Raitanen
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Filip S. Ekholm
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Kirsi J. Svedström
- Department
of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| |
Collapse
|
7
|
Kokkinakis J, Schuett BS, Millar TJ. Effects on the Human Tear Film of Applying Skin Lipids to the Ocular Surface. Cornea 2023; 42:1562-1571. [PMID: 37506368 DOI: 10.1097/ico.0000000000003345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 06/05/2023] [Indexed: 07/30/2023]
Abstract
PURPOSE The effect of skin lipids on the formation and stability of the human tear film was investigated. METHODS Skin swab substances (SSSs) were applied to the eyes of volunteers and studied using fluorescein or with TearView, which records infrared emissivity showing tear film integrity in real time. Results were compared with similar experiments using castor oil, freshly collected meibum, or acetic acid, which simulated the low pH of the skin. RESULTS Fluorescein and TearView results were comparable. TearView showed the natural unaltered tear film over the whole eye, instant changes to the tear film, and meibomian gland activity. Minimal amounts of SSS destroyed the integrity of the film and caused pain. Corneal epithelial damage could be detected. TearView showed that SSS stimulated meibomian gland secretion if applied directly to the posterior eyelid margin. Excess meibum had no effect on the tear film spread or integrity. Castor oil formed floating lenses on the tear film which were spread by a blink but then condensed back toward themselves. There was no pain or surface damage with these oils. CONCLUSIONS SSS contamination of the ocular surface disrupts the tear film, causes stinging, and fluorescein staining of the corneal epithelial cells after a blink. SSS stimulates meibomian gland activity. It is possible that various ocular conditions associated with dry eye, such as blepharitis and ocular rosacea, may compromise a meibomian lipid barrier of the eye lid margin. Skin lipids would then have access to the ocular surface and cause dry eye symptoms.
Collapse
Affiliation(s)
- Jim Kokkinakis
- School of Medicine, Western Sydney University, Sydney, NSW, Australia
- The Eye Practice, Sydney, NSW, Australia; and
| | | | | |
Collapse
|
8
|
Yazdani M. Tear film lipid layer and corneal oxygenation: a new function? Eye (Lond) 2023; 37:3534-3541. [PMID: 37138094 PMCID: PMC10686381 DOI: 10.1038/s41433-023-02557-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/22/2023] [Accepted: 04/20/2023] [Indexed: 05/05/2023] Open
Abstract
The classic model of tear film is composed of mucin layer, aqueous layer and the outermost tear film lipid layer (TFLL). The complex mixture of different classes of lipids, mainly secreted by meibomian glands, gives the TFLL unique physicochemical properties. Based on these properties, several functions of TFLL have been found and/or proposed such as the resistance to evaporation and facilitating the formation of a thin film. However, the role of TFLL in the oxygenation of the cornea, a transparent avascular tissue, has never been discussed in the literature. The continuous metabolic activity of the corneal surface and the replenishment of atmospheric gas creates an O2 gradient in the tear film. The molecules of O2 must therefore be transferred from the gas phase to the liquid phase through the TFLL. This process is a function of the diffusion and solubility of the lipid layer as well as interface transfer, which is influenced by alterations in the physical state and lipid composition. In the absence of research on TFLL, the present paper aims to bring the topic into the spotlight for the first time based on existing knowledge on O2 permeability of the lipid membranes and evaporation resistance of the lipid layers. The oxidative stress generated in perturbed lipid layers and the consequent adverse effects are also covered. The function of the TFLL proposed here intends to encourage future research in both basic and clinical sciences, e.g., opening new avenues for the diagnosis and treatment of ocular surface conditions.
Collapse
Affiliation(s)
- Mazyar Yazdani
- Department of Medical Biochemistry, Oslo University Hospital, Rikshospitalet, 0027, Oslo, Norway.
| |
Collapse
|
9
|
Dong S, Zhang N, Yi M, Zhang J, Di D, Deng J, Li L, Hu B. Slug-Flow Microextraction Mass Spectrometry for Enhanced Detection of Analytes in Human Tear Fluids using Noninvasive Microsampling and Nanoelectrospray Ionization via a Capillary. Anal Chem 2023; 95:16054-16058. [PMID: 37852267 DOI: 10.1021/acs.analchem.3c03683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
In vivo noninvasive sampling and sensitive analysis of human tear fluids at the microliter level is an important but challenging task in investigating eye health. In this work, capillary microsampling coupled with slug-flow microextraction mass spectrometry (SFME-MS) was developed for enhanced detection of analytes in human tear fluids. As low as 1.0 μL of human tear fluid could be directly sampled using a capillary, and extraction/spray solvent was then loaded into the capillary to perform slug-flow microextraction and direct nanoelectrospray ionization (nESI) of analytes. All analytical procedures, including tear microsampling, microextraction, and ionization of analytes, were performed using a capillary. Enhanced detection of therapeutic drugs and disease biomarkers in human tear fluids was successfully demonstrated. Acceptable analytical performances including sensitivity, reproducibility, and quantitation were obtained. It is found that the use of SFME could improve the nESI-MS detection of trace analytes over 100-fold that depends on the chemical properties of analytes. Overall, this study showed that SFME-nESI-MS is a highly effective method for enhanced detection of trace analytes in tear fluids and is expected to be a potentially powerful tool in significant biological and clinical applications.
Collapse
Affiliation(s)
- Songbin Dong
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangdong Provincial Key Laboratory of Speed Capability Research, Jinan University, Guangzhou 510632, China
| | - Ning Zhang
- Ophthalmology Department, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710064, China
| | - Man Yi
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangdong Provincial Key Laboratory of Speed Capability Research, Jinan University, Guangzhou 510632, China
| | - Jianfeng Zhang
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangdong Provincial Key Laboratory of Speed Capability Research, Jinan University, Guangzhou 510632, China
| | - Dandan Di
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangdong Provincial Key Laboratory of Speed Capability Research, Jinan University, Guangzhou 510632, China
| | - Jiewei Deng
- School of Biomedical and Pharmaceutical Sciences, Smart Medical Innovation Technology Center, Guangdong University of Technology, Guangzhou 510006, China
| | - Lei Li
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangdong Provincial Key Laboratory of Speed Capability Research, Jinan University, Guangzhou 510632, China
| | - Bin Hu
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangdong Provincial Key Laboratory of Speed Capability Research, Jinan University, Guangzhou 510632, China
| |
Collapse
|
10
|
Moreno I, Verma S, Gesteira TF, Coulson-Thomas VJ. Recent advances in age-related meibomian gland dysfunction (ARMGD). Ocul Surf 2023; 30:298-306. [PMID: 37979775 PMCID: PMC11092925 DOI: 10.1016/j.jtos.2023.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 11/02/2023] [Accepted: 11/13/2023] [Indexed: 11/20/2023]
Abstract
Meibomian glands (MGs), located within the tarsal plate of the eyelid, secrete meibum which is the lipid-rich secretion necessary for stabilizing the tear film and preventing tear evaporation. Changes in the quality and quantity of meibum produced causes MG dysfunction (MGD), the leading cause of evaporative dry eye disease (EDED). MGD is an underdiagnosed disease and it is estimated that, in the US, approximately 70 % of the population over 60 have MGD. Three forms of MGD occur based on their meibum secretion: hyposecretory, obstructive, and hypersecretory MGD. The pathophysiology of MGD remains poorly understood, however aging is the primary risk factor. With age, MGs undergo various age-related changes, including decreased acinar basal cell proliferation, hyperkeratinization, MG atrophy, and eventual MG drop-out, leading to age-related MGD (ARMGD). Additionally, studies have suggested that MGs can suffer inflammatory cell infiltration and changes innervation patterns with aging, which could also contribute towards ARMGD. This review focuses on how the aging process affects the MG, and more importantly, how age-related changes to the MG can lead to MG atrophy and MG drop-out, ultimately leading to ARMGD. This review also highlights the most recent developments in potential therapeutic interventions for ARMGD.
Collapse
Affiliation(s)
| | - Sudhir Verma
- College of Optometry, University of Houston, USA; Department of Zoology, Deen Dayal Upadhyaya College, University of Delhi, Delhi, India.
| | | | | |
Collapse
|
11
|
Xu X, Wilkerson A, Li G, Butovich IA, Zuo YY. Comparative Biophysical Study of Meibomian Lipids of Wild Type and Soat1-Null Mice: Implications to Meibomian Gland Dysfunction and Dry Eye Disease. Invest Ophthalmol Vis Sci 2023; 64:20. [PMID: 37585190 PMCID: PMC10434715 DOI: 10.1167/iovs.64.11.20] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/28/2023] [Indexed: 08/17/2023] Open
Abstract
Purpose The biophysical roles of Meibomian lipids (MLs) played in health and meibomian gland dysfunction (MGD) are still unclear. The purpose of this research is to establish the composition-structure-functional correlations of the ML film (MLF) using Soat1-null mice and comprehensive in vitro biophysical simulations. Methods MLs were extracted from tarsal plates of wild type (WT) and Soat1 knockout (KO) mice. The chemical composition of ML samples was characterized using liquid chromatography - mass spectrometry. Comprehensive biophysical studies of the MLFs, including their dynamic surface activity, interfacial rheology, evaporation resistance, and ultrastructure and topography, were performed with a novel experimental methodology called the constrained drop surfactometry. Results Soat1 inactivation caused multiple alternations in the ML profile. Compared to their WT siblings, the MLs of KO mice were completely devoid of cholesteryl esters (CEs) longer than C18 to C20, but contained 7 times more free cholesterol (Chl). Biophysical assays consistently suggested that the KO-MLF became stiffer than that of WT mice, revealed by reduced film compressibility, increased elastic modulus, and decreased loss tangent, thus causing more energy loss per blinking cycle of the MLF. Moreover, the KO mice showed thinning of their MLF, and reduced evaporation resistance. Conclusions These findings delineated the composition-structure-functional correlations of the MLF and suggested a potential biophysical function of long-chain CEs in optimizing the surface activity, interfacial rheology, and evaporation resistance of the MLF. This study may provide novel implications to pathophysiological and translational understanding of MGD and dry eye disease.
Collapse
Affiliation(s)
- Xiaojie Xu
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States
| | - Amber Wilkerson
- Department of Ophthalmology and Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Guangle Li
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States
| | - Igor A. Butovich
- Department of Ophthalmology and Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Yi Y. Zuo
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States
- Department of Pediatrics, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, United States
| |
Collapse
|
12
|
Nagar S, Ajouz L, Nichols KK, Kumar S, Zhao C, Naidoo KK, Robinson MR, Borchman D. Relationship Between Human Meibum Lipid Composition and the Severity of Meibomian Gland Dysfunction: A Spectroscopic Analysis. Invest Ophthalmol Vis Sci 2023; 64:22. [PMID: 37466951 PMCID: PMC10362926 DOI: 10.1167/iovs.64.10.22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023] Open
Abstract
Purpose Information on the relationship between meibum lipid composition and severity of meibomian gland dysfunction (MGD) is limited. The purpose of this study was to analyze the molecular components of meibum collected from individuals with no MGD, mild-to-moderate MGD, and severe MGD. Methods Adults with and without MGD were enrolled in a prospective, multicenter, exploratory clinical trial (ClinicalTrials.gov Identifier: NCT01979887). Molar ratios of cholesteryl ester to wax ester (RCE/WE) and aldehyde to wax ester (Rald/WE) in meibum samples were measured with 1H-NMR spectroscopy. Results were evaluated for participants grouped by MGD disease status and severity (non-MGD, mild-to-moderate MGD, and severe MGD), as defined by maximum meibum quality scores, Schirmer test results, and Subject Ocular Symptom Questionnaire responses. Results Sixty-nine meibum samples from 69 individuals were included in the analysis: 24 non-MGD, 24 mild-to-moderate MGD, and 21 severe MGD. Mean RCE/WE was 0.29 in non-MGD, 0.14 in mild-to-moderate MGD (P = 0.038 vs. non-MGD, 51% lower), and 0.07 in severe MGD (P = 0.16 vs. mild-to-moderate MGD, 52% lower; P = 0.002 vs. non-MGD, 76% lower). Mean Rald/WE was 0.00022 in non-MGD, 0.00083 in mild-to-moderate MGD (P = 0.07 vs. non-MGD, 277% higher), and 0.0024 in severe MGD (P = 0.003 vs. mild-to-moderate MGD, 190% higher; P < 0.001 vs. non-MGD, 992% higher). Conclusions RCE/WE was lowest and Rald/WE was highest in the severe MGD cohort, suggesting that these meibum constituent molar ratios may result from the pathophysiology associated with MGD and can impact ocular surface lipid and tear film homeostasis. These findings may potentially help identify targets for MGD treatment.
Collapse
Affiliation(s)
- Saumya Nagar
- Allergan, an AbbVie company, Irvine, CA, United States
| | - Layla Ajouz
- Allergan, an AbbVie company, Irvine, CA, United States
| | - Kelly K Nichols
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Sandeep Kumar
- Allergan, an AbbVie company, Irvine, CA, United States
| | - Cathy Zhao
- Allergan, an AbbVie company, Irvine, CA, United States
| | - Kugen K Naidoo
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY, United States
| | | | - Douglas Borchman
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY, United States
| |
Collapse
|
13
|
Verma S, Moreno IY, Trapp ME, Ramirez L, Gesteira TF, Coulson-Thomas VJ. Meibomian gland development: Where, when and how? Differentiation 2023; 132:41-50. [PMID: 37202278 PMCID: PMC11259229 DOI: 10.1016/j.diff.2023.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 04/10/2023] [Accepted: 04/30/2023] [Indexed: 05/20/2023]
Abstract
The Meibomian gland (MG) is an indispensable adnexal structure of eye that produces meibum, an important defensive component for maintaining ocular homeostasis. Normal development and maintenance of the MGs is required for ocular health since atrophic MGs and disturbances in composition and/or secretion of meibum result in major ocular pathologies, collectively termed as Meibomian gland dysfunction (MGD). Currently available therapies for MGD merely provide symptomatic relief and do not treat the underlying deficiency of the MGs. Hence, a thorough understanding of the timeline of MG development, maturation and aging is required for regenerative purposes along with signaling molecules & pathways controlling proper differentiation of MG lineage in mammalian eye. Understanding the factors that contribute to the development of MGs, developmental abnormalities of MGs, and changes in the quality & quantity of meibum with developing phases of MGs are essential for developing potential treatments for MGD. In this review, we compiled a timeline of events and the factors involved in the structural and functional development of MGs and the associated developmental defects of MGs during development, maturation and aging.
Collapse
Affiliation(s)
- Sudhir Verma
- College of Optometry, University of Houston, Houston, TX, USA; Department of Zoology, Deen Dayal Upadhyaya College, University of Delhi, New Delhi, India
| | - Isabel Y Moreno
- College of Optometry, University of Houston, Houston, TX, USA
| | - Morgan E Trapp
- College of Optometry, University of Houston, Houston, TX, USA
| | - Luis Ramirez
- College of Optometry, University of Houston, Houston, TX, USA
| | | | | |
Collapse
|
14
|
Amano S, Shimazaki J, Yokoi N, Hori Y, Arita R. Meibomian Gland Dysfunction Clinical Practice Guidelines. Jpn J Ophthalmol 2023; 67:448-539. [PMID: 37351738 DOI: 10.1007/s10384-023-00995-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 12/21/2022] [Indexed: 06/24/2023]
Affiliation(s)
- Shiro Amano
- Ochanomizu Inoue Eye Clinic, 4-3 Kandasurugadai, Chiyoda-ku, Tokyo, 101-0062, Japan.
| | - Jun Shimazaki
- Department of Ophthalmology, Tokyo Dental College Ichikawa General Hospital, Ichikawa, Japan
| | - Norihiko Yokoi
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yuichi Hori
- Department of Ophthalmology, Toho University Omori Medical Center, Tokyo, Japan
| | | |
Collapse
|
15
|
Ooi KG, Watson SL. Rosacea Meibomian Gland Dysfunction Posterior Blepharitis May Be a Marker for Earlier Associated Dyslipidaemia and Inflammation Detection and Treatment with Statins. Metabolites 2023; 13:811. [PMID: 37512518 PMCID: PMC10384312 DOI: 10.3390/metabo13070811] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 06/18/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
Posterior blepharitis and dry eye are common disorders with meibomian gland dysfunction (MGD), a principal driver of their pathophysiology. Meibomian gland dysfunction is increasingly prevalent in older populations with contributory hormonal imbalances. The abnormal meibum in MGD has been documented to have an excess of cholesterol with a resultant disruption of the lipid layer of the tear film. This leads to tear film instability due to the inadequate trapping of the aqueous portion of the tear film with resultant evaporative dry eye. Significant morbidity may follow MGD with ocular surface inflammation disrupting both social and work function. Rosacea is a common chronic inflammatory condition of the central face but can have ocular and systemic inflammatory associations. It is especially prevalent in North European populations and can have onset at any age, but commonly presents between thirty and fifty years of age. In ocular rosacea, MGD is a recognised manifestation as is dyslipidaemia. Ocular rosacea can predate cutaneous disease. As yet, there is no directly reported evidence of the efficacy of the early identification and treatment of ocular rosacea with associated dyslipidaemia and systemic inflammation. We posit that MGD in ocular rosacea sufferers may be a marker for dysregulated cholesterol synthesis and inflammation, and that statins maybe a potential therapy. This article introduces potential strategies to utilise ocular rosacea MGD as a possible marker for ophthalmologists, cardiologists, and primary healthcare physicians to treat rosacea-associated dyslipidaemia and systemic inflammation. This could aid in overall cardiovascular morbidity and mortality control for rosacea sufferers, potentially at an earlier age, while also addressing their tear film de-stabilisation through cholesterol lowering and inflammation reduction.
Collapse
Affiliation(s)
- Kenneth G Ooi
- Corneal Research Group, Discipline of Ophthalmology, Save Sight Institute, Sydney Eye Hospital Campus, Sydney, NSW 2000, Australia
- School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Stephanie L Watson
- Corneal Research Group, Discipline of Ophthalmology, Save Sight Institute, Sydney Eye Hospital Campus, Sydney, NSW 2000, Australia
| |
Collapse
|
16
|
Baksheeva VE, Tiulina VV, Iomdina EN, Petrov SY, Filippova OM, Kushnarevich NY, Suleiman EA, Eyraud R, Devred F, Serebryakova MV, Shebardina NG, Chistyakov DV, Senin II, Mitkevich VA, Tsvetkov PO, Zernii EY. Tear nanoDSF Denaturation Profile Is Predictive of Glaucoma. Int J Mol Sci 2023; 24:ijms24087132. [PMID: 37108298 PMCID: PMC10139145 DOI: 10.3390/ijms24087132] [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: 03/17/2023] [Revised: 04/07/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023] Open
Abstract
Primary open-angle glaucoma (POAG) is a frequent blindness-causing neurodegenerative disorder characterized by optic nerve and retinal ganglion cell damage most commonly due to a chronic increase in intraocular pressure. The preservation of visual function in patients critically depends on the timeliness of detection and treatment of the disease, which is challenging due to its asymptomatic course at early stages and lack of objective diagnostic approaches. Recent studies revealed that the pathophysiology of glaucoma includes complex metabolomic and proteomic alterations in the eye liquids, including tear fluid (TF). Although TF can be collected by a non-invasive procedure and may serve as a source of the appropriate biomarkers, its multi-omics analysis is technically sophisticated and unsuitable for clinical practice. In this study, we tested a novel concept of glaucoma diagnostics based on the rapid high-performance analysis of the TF proteome by differential scanning fluorimetry (nanoDSF). An examination of the thermal denaturation of TF proteins in a cohort of 311 ophthalmic patients revealed typical profiles, with two peaks exhibiting characteristic shifts in POAG. Clustering of the profiles according to peaks maxima allowed us to identify glaucoma in 70% of cases, while the employment of artificial intelligence (machine learning) algorithms reduced the amount of false-positive diagnoses to 13.5%. The POAG-associated alterations in the core TF proteins included an increase in the concentration of serum albumin, accompanied by a decrease in lysozyme C, lipocalin-1, and lactotransferrin contents. Unexpectedly, these changes were not the only factor affecting the observed denaturation profile shifts, which considerably depended on the presence of low-molecular-weight ligands of tear proteins, such as fatty acids and iron. Overall, we recognized the TF denaturation profile as a novel biomarker of glaucoma, which integrates proteomic, lipidomic, and metallomic alterations in tears, and monitoring of which could be adapted for rapid non-invasive screening of the disease in a clinical setting.
Collapse
Affiliation(s)
- Viktoriia E Baksheeva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 1-40 Leninskye Gory, 119992 Moscow, Russia
- Institut Neurophysiopathol, INP, Faculté des Sciences Médicales et Paramédicales, Aix Marseille Univ, CNRS, 13005 Marseille, France
| | - Veronika V Tiulina
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 1-40 Leninskye Gory, 119992 Moscow, Russia
| | - Elena N Iomdina
- Helmholtz National Medical Research Center of Eye Diseases, 105062 Moscow, Russia
| | - Sergey Yu Petrov
- Helmholtz National Medical Research Center of Eye Diseases, 105062 Moscow, Russia
| | - Olga M Filippova
- Helmholtz National Medical Research Center of Eye Diseases, 105062 Moscow, Russia
| | - Nina Yu Kushnarevich
- Helmholtz National Medical Research Center of Eye Diseases, 105062 Moscow, Russia
| | - Elena A Suleiman
- Helmholtz National Medical Research Center of Eye Diseases, 105062 Moscow, Russia
| | - Rémi Eyraud
- Université Jean Monnet Saint-Etienne, CNRS, Institut d Optique Graduate School, Laboratoire Hubert Curien UMR 5516, 42023 Saint-Etienne, France
| | - François Devred
- Institut Neurophysiopathol, INP, Faculté des Sciences Médicales et Paramédicales, Aix Marseille Univ, CNRS, 13005 Marseille, France
| | - Marina V Serebryakova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 1-40 Leninskye Gory, 119992 Moscow, Russia
| | - Natalia G Shebardina
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 1-40 Leninskye Gory, 119992 Moscow, Russia
| | - Dmitry V Chistyakov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 1-40 Leninskye Gory, 119992 Moscow, Russia
| | - Ivan I Senin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 1-40 Leninskye Gory, 119992 Moscow, Russia
| | - Vladimir A Mitkevich
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Philipp O Tsvetkov
- Institut Neurophysiopathol, INP, Faculté des Sciences Médicales et Paramédicales, Aix Marseille Univ, CNRS, 13005 Marseille, France
| | - Evgeni Yu Zernii
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 1-40 Leninskye Gory, 119992 Moscow, Russia
| |
Collapse
|
17
|
Classification of Tear Film Lipid Layer En Face Maps Obtained Using Optical Coherence Tomography and Their Correlation With Clinical Parameters. Cornea 2023; 42:490-497. [PMID: 36730374 PMCID: PMC9973450 DOI: 10.1097/ico.0000000000003172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/31/2022] [Indexed: 02/04/2023]
Abstract
PURPOSE The purpose of this study was to investigate the correlation between the pattern of optical coherence tomography (OCT) en face maps of the tear film lipid layer (TFLL) and lipid layer thickness (LLT), fluorescein breakup time (FBUT), and Schirmer I test values in healthy subjects. METHODS Measurements from four clinical data sets were retrospectively analyzed, and TFLL patterns were classified into 3 categories: homogeneous (HOM), wavy (WAV), or dotted (DOT) appearance. Linear mixed model analyses were performed. Intraclass correlation coefficients and index of qualitative variation were computed to investigate interrater and intrasubject variabilities. RESULTS For the LLT, a significant difference between HOM and DOT ( P < 0.001, β HOMvsDOT = -6.42 nm) and WAV and DOT ( P = 0.002, β WAVvsDOT = -4.04 nm) was found. Furthermore, the difference between WAV and DOT regarding FBUT ( P < 0.001, β WAVvsDOT = -3.065 seconds) was significant, while no significant differences between any of the classes with respect to the Schirmer I test values were found. An intraclass correlation coefficient of 89.0% reveals a good interrater reliability, and an index of qualitative variation of 60.0% shows, on average, a considerable variability in TFLL pattern class for repeated measurements over 1 hour. CONCLUSIONS A new classification method for OCT en face maps of the TFLL is presented. Significant differences between patterns were found with respect to LLT and FBUT. A dotted pattern on dark background appears to be the most stable type of TFLL. The analysis of OCT en face maps of the TFLL provides complimentary information to conventional imaging methods and might give new insights into the characteristics of the TFLL.
Collapse
|
18
|
Metabolomics in Corneal Diseases: A Narrative Review from Clinical Aspects. Metabolites 2023; 13:metabo13030380. [PMID: 36984820 PMCID: PMC10055016 DOI: 10.3390/metabo13030380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/25/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023] Open
Abstract
Corneal pathologies may have subtle manifestations in the initial stages, delaying diagnosis and timely treatment. This can lead to irreversible visual loss. Metabolomics is a rapidly developing field that allows the study of metabolites in a system, providing a complementary tool in the early diagnosis and management of corneal diseases. Early identification of biomarkers is key to prevent disease progression. The advancement of nuclear magnetic resonance and mass spectrometry allows the identification of new biomarkers in the analysis of tear, cornea, and aqueous humor. Novel perspectives on disease mechanisms are identified, which provide vital information for potential targeted therapies in the future. Current treatments are analyzed at a molecular level to offer further information regarding their efficacy. In this article, we provide a comprehensive review of the metabolomic studies undertaken in the cornea and various pathologies such as dry eye disease, Sjogren’s syndrome, keratoconus, post-refractive surgery, contact lens wearers, and diabetic corneas. Lastly, we discuss the exciting future that metabolomics plays in cornea research.
Collapse
|
19
|
Viitaja T, Raitanen JE, Moilanen J, Paananen RO, Ekholm FS. Biophysical profiling of synthetic ultra-long tear film lipids. Colloids Surf B Biointerfaces 2023; 223:113145. [PMID: 36701899 DOI: 10.1016/j.colsurfb.2023.113145] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/04/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023]
Abstract
The tear film lipid layer (TFLL) is a unique biological membrane of importance to the maintenance of ocular surface health. The underlying factors at play, e.g. the ability to retard evaporation and offer protection from the environment, are all closely connected to the properties of individual lipid components and their interplay. The TFLL contains unique ultra-long polar lipid species such as O-acyl-ω-hydroxy fatty acids, type I-St diesters and type II diesters, which are considered important for its proper function. Herein, we have synthesized model compounds from these categories and studied their biophysical and surface rheological properties at the aqueous interface. Altogether, we provide insights on the distinct biophysical profiles of these lipid classes and discuss how their interplay may affect the structure and function of the TFLL.
Collapse
Affiliation(s)
- Tuomo Viitaja
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland; Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, FI-00290 Helsinki, Finland
| | - Jan-Erik Raitanen
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Jukka Moilanen
- Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, FI-00290 Helsinki, Finland
| | - Riku O Paananen
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland; Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, FI-00290 Helsinki, Finland.
| | - Filip S Ekholm
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland.
| |
Collapse
|
20
|
Keramatnejad M, DeWolf C. A biophysical study of tear film lipid layer model membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184102. [PMID: 36535341 DOI: 10.1016/j.bbamem.2022.184102] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/22/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
The tear film lipid layer (TFLL), the final layer of the human tear film is responsible for surface tension reduction while blinking, water evaporation retardation and maintaining the stability of the tear film. The study of the composition-structure-function relationship of TFLL is paramount, as a compromised structure of TFLL leads to the emergence of dry eye disease (DED) which is one the most prevalent ophthalmic surface diseases of the modern world, associated with chronic pain and reduced visual capability. In this model membrane study, a systematic approach is used to study the biophysical properties of TFLL model membranes as a function of composition. Three mixed-lipid model membranes are studied along with their individual components comprising cholesteryl oleate (CO), glyceryl trioleate (GT), L-α-phosphatidylcholine (egg PC) and a free fatty acid mixture. The models become progressively more complex from binary to quaternary mixtures, allowing the role of each individual lipid to be derived. Langmuir balance, Brewster Angle Microscopy (BAM) and Profile Analysis Tensiometer (PAT) are used to study the surface activity and compression-expansion cycles, morphology, and rheological behaviour of the model membranes, respectively. Evidence of multilayering is observed with inclusion of CO and a reversible collapse is associated with the GT phase transition. An initially more coherent film is observed due to the addition of polar PC. Notably, these individual behaviours are retained in the mixed films and suggest a possible role for each physiological component of TFLL.
Collapse
Affiliation(s)
- Mahshid Keramatnejad
- Department of Chemistry & Biochemistry, Centre for Nanoscience Research, Concordia University,7141 Sherbrooke Street west, H4B1R6 Montreal, Canada.
| | - Christine DeWolf
- Department of Chemistry & Biochemistry, Centre for Nanoscience Research, Concordia University,7141 Sherbrooke Street west, H4B1R6 Montreal, Canada.
| |
Collapse
|
21
|
Keramatnejad M, DeWolf C. Impact of Pollutant Ozone on the Biophysical Properties of Tear Film Lipid Layer Model Membranes. MEMBRANES 2023; 13:165. [PMID: 36837668 PMCID: PMC9964828 DOI: 10.3390/membranes13020165] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/17/2023] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
Ozone exposure from environmental smog has been implicated as a risk factor for developing dry eye disease (DED). The tear film lipid layer (TFLL), which is the outermost layer of the tear film and responsible for surface tension reduction while blinking, is in direct contact with the environment and serves as the first line of defense against external aggressors such as environmental pollution. The impact of exposure to ozone on the biophysical properties of three TFLL model membranes was investigated. These model membranes include a binary mixture of cholesteryl oleate (CO) and L-α-phosphatidylcholine (egg PC), a ternary mixture of CO, glyceryl trioleate (GT) and PC, as well as a quaternary mixture of CO, GT, a mixture of free fatty acids palmitic acid and stearic acid (FFAs) and PC. Biophysical impacts were evaluated as changes to the surface activity, respreadability, morphology and viscoelastic properties of the films. Expansion to higher molecular areas was observed in all the TFLL model membrane films which is attributable to the accommodation of the cleaved chains in the film. Significant morphological changes were observed, namely fluidization and the disruption of the phase transition behaviour of GT, and multilayer formation of CO. This fluidization reduces the hysteresis loops for the model membranes. On the other hand, the viscoelastic properties of the films exhibited differential impacts from ozone exposure as a function of composition. These findings are correlated to chemical changes to the lipids determined using ESI-MS.
Collapse
|
22
|
Xu X, Li G, Zuo YY. Effect of Model Tear Film Lipid Layer on Water Evaporation. Invest Ophthalmol Vis Sci 2023; 64:13. [PMID: 36656568 PMCID: PMC9872843 DOI: 10.1167/iovs.64.1.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Purpose A majority of in vitro models were incapable of reproducing the evaporation resistance of tear film lipid layer (TFLL) in vivo. The purpose of this research is to develop a novel in vitro model to study the effect of TFLL on water evaporation. Methods A ventilated, closed-chamber, droplet evaporimeter with a constant surface area has been invented to study the evaporation resistance of TFLL. This evaporimeter ensures a rigorous control of environmental conditions, including the temperature, relative humidity, airflow rate, surface area, and surface pressure, thus allowing for reproducible water evaporation measurements over a time period of only 5 minutes. The volumetric evaporation rate of this droplet evaporimeter is less than 2.7 µL/min, comparable to the basal tear production of healthy adults. Together with direct film imaging using atomic force microscopy (AFM), we have studied the effect of a model TFLL on water evaporation, as a function of the lipid composition and surface pressure. Results A model TFLL composed of 40% wax esters, 40% cholesteryl esters, and 20% polar lipids was capable of reducing the water evaporation rate by 11% at surface pressure 47 mN/m. AFM revealed that the model TFLL at high surface pressures consists of discrete droplets/aggregates of the nonpolar lipids residing atop a polar lipid monolayer with phase separation. Conclusions The TFLL may resist water evaporation with a combined mechanism by increasing film compactness of the polar lipid film at the air-water surface, and, to a lesser extent, by increasing film thickness of the nonpolar lipid film.
Collapse
Affiliation(s)
- Xiaojie Xu
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States
| | - Guangle Li
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States
| | - Yi Y. Zuo
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States,Department of Pediatrics, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, United States
| |
Collapse
|
23
|
Walker MK, Bailey LS, Basso KB, Redfern RR. Nonpolar Lipids Contribute to Midday Fogging During Scleral Lens Wear. Invest Ophthalmol Vis Sci 2023; 64:7. [PMID: 36630141 PMCID: PMC9840443 DOI: 10.1167/iovs.64.1.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Purpose To determine correlations between lipids in the fluid reservoir (FR) and the severity of midday fogging (MDF) in scleral lens (SL) wear. Methods SL neophytes were recruited to wear custom SL for 4 days, examined after 8 hours on days 1 and 4. Lens vault and MDF were quantified from anterior segment optical coherence tomography (AS-OCT), and the FR was collected and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Relative abundance of lipids was compared to MDF scores using nonparametric correlation testing (Spearman rank). Ocular surface and SL fitting characteristics (lens vault, fitting curves) were likewise compared to MDF. Results Thirteen participants (26 eyes, 69% female, 28 ± 9 years old) were included in this study. MDF severity after 8 hours of SL wear was 33 ± 29 units on day 1 and 28 ± 24 units on day 4 (r = .94; P < 0.01). Twelve samples were analyzed using LC-MS/MS, and a total of 170 distinct lipid species were detected. The lipid classes with greatest correlation to MDF were the wax esters (r = .73, P = 0.01), cholesteryl esters (r = .59; P = 0.049), and triacylglycerols (r = .64, P = 0.03). Polar lipids were observed abundantly in all samples. None of the measured ocular surface or fitting outcomes were correlated to MDF. Conclusions Nonpolar lipids were the greatest contributors to MDF among these normal participants. Polar lipids may be due to cellular debris, although they do not appear contributory to MDF.
Collapse
Affiliation(s)
- Maria K. Walker
- College of Optometry, The Ocular Surface Institute, University of Houston, Houston, Texas, United States
| | - Laura S. Bailey
- Department of Chemistry, University of Florida, Gainesville, Florida, United States
| | - Kari B. Basso
- Department of Chemistry, University of Florida, Gainesville, Florida, United States
| | - Rachel R. Redfern
- College of Optometry, The Ocular Surface Institute, University of Houston, Houston, Texas, United States
| |
Collapse
|
24
|
Xu X, Zuo YY. Nanomedicine for Ocular Drug Delivery. Nanomedicine (Lond) 2023. [DOI: 10.1007/978-981-16-8984-0_32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
|
25
|
Magny R, Regazzetti A, Kessal K, Christin O, Baudouin C, Roulland E, Brignole-Baudouin F, Laprévote O, Auzeil N. Identification of new Omega-3 very long chain poly-unsaturated fatty acids in meibomian gland secretions. Biochimie 2022; 203:3-10. [PMID: 35476941 DOI: 10.1016/j.biochi.2022.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 03/14/2022] [Accepted: 04/19/2022] [Indexed: 12/16/2022]
Abstract
Three new very long chain polyunsaturated fatty acids (VLC PUFA) belonging to the omega-3 family have been identified in meibum samples collected by Schirmer strips. These VLC PUFA, namely FA (32:3), FA (34:3) and FA (36:3), were detected in O-acyl-ω-hydroxy fatty acids using a molecular network approach, and as free fatty acids. Identification was supported by retention time prediction model, exact mass determination and isotopic patterns. Double bond location was determined using cross metathesis reaction associated to tandem mass spectrometry. In meibum, synthesis of these VLC PUFA is likely to be mediated by elongation of very long chain fatty acids 4 enzyme. The biological role of these newly VLC PUFA and their occurrence in other tissues and biological fluids remains to be elucidated.
Collapse
Affiliation(s)
- Romain Magny
- Sorbonne Université UM80, INSERM UMR 968, CNRS UMR 7210, Institut de la Vision, IHU ForeSight, 75012, Paris, France; Université Paris Cité, CNRS, CiTCoM, F-75006, Paris, France.
| | | | - Karima Kessal
- Sorbonne Université UM80, INSERM UMR 968, CNRS UMR 7210, Institut de la Vision, IHU ForeSight, 75012, Paris, France; CIC 1423, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, IHU ForeSight, 75012, Paris, France
| | - Orane Christin
- Université Paris Cité, CNRS, CiTCoM, F-75006, Paris, France
| | - Christophe Baudouin
- Sorbonne Université UM80, INSERM UMR 968, CNRS UMR 7210, Institut de la Vision, IHU ForeSight, 75012, Paris, France; CIC 1423, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, IHU ForeSight, 75012, Paris, France; Hôpital Ambroise Paré, AP-HP, Université Versailles St Quentin en Yvelines, Paris Saclay, 78180, Montigny-Le-Bretonneux, France
| | | | - Françoise Brignole-Baudouin
- Sorbonne Université UM80, INSERM UMR 968, CNRS UMR 7210, Institut de la Vision, IHU ForeSight, 75012, Paris, France; Université Paris Cité, CNRS, CiTCoM, F-75006, Paris, France; Laboratoire d'ophtalmobiologie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, IHU ForeSight, 75012, Paris, France
| | - Olivier Laprévote
- Université Paris Cité, CNRS, CiTCoM, F-75006, Paris, France; Hôpital Européen Georges Pompidou, AP-HP, Service de Biochimie, 75015, Paris, France
| | - Nicolas Auzeil
- Université Paris Cité, CNRS, CiTCoM, F-75006, Paris, France.
| |
Collapse
|
26
|
Daull P, Baudouin C, Liang H, Feraille L, Barabino S, Garrigue JS. Review of Preclinical Outcomes of a Topical Cationic Emulsion of Cyclosporine A for the Treatment of Ocular Surface Diseases. Ocul Immunol Inflamm 2022; 30:1945-1955. [PMID: 34348575 DOI: 10.1080/09273948.2021.1957124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Cyclosporine A (CsA) has been used as a topical treatment for various ocular surface diseases including dry eye disease (DED). Several CsA formulations are available as solutions or emulsions. PURPOSE This review describes the development and the preclinical testing of a cationic oil-in-water emulsion of CsA (CE-CsA) in terms of pharmacodynamics, pharmacokinetics, and ocular tolerance. Due to the cationic charge, CE electrostatically interacts with the negatively-charged ocular surface, improving its residence time. Compared to other CsA formulations, CE-CsA and CE itself were found to reduce the signs and symptoms of DED, by restoring tear film stability and properties, and inhibiting the expression and secretion of pro-inflammatory factors. No delay in wound healing nor ocular toxicity were observed using CE formulations. CONCLUSION these findings indicate that the type of vehicle can significantly affect the performance of eye drops and play an ancillary role in DED treatment. CE appears as a promising strategy to deliver drugs to the ocular surface while maintaining its homeostasis.
Collapse
Affiliation(s)
| | - Christophe Baudouin
- CHNO des Quinze-Vingts, IHU FOReSIGHT, INSERM-DGOS CIC 1423, Paris, France.,Sorbonne Universités, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Hong Liang
- CHNO des Quinze-Vingts, IHU FOReSIGHT, INSERM-DGOS CIC 1423, Paris, France.,Sorbonne Universités, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Stefano Barabino
- Ocular Surface and Dry Eye Center, Ospedale L. Sacco, University of Milan, Milan, Italy
| | | |
Collapse
|
27
|
Association of Serum Lipid Level with Meibum Biosynthesis and Meibomian Gland Dysfunction: A Review. J Clin Med 2022; 11:jcm11144010. [PMID: 35887773 PMCID: PMC9323051 DOI: 10.3390/jcm11144010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/27/2022] [Accepted: 07/05/2022] [Indexed: 11/16/2022] Open
Abstract
The primary role of meibomian glands (MGs) is to actively synthesize and secret lipids and proteins spread onto the tear film, and the glandular lipids promote tear stability, prevent evaporation, and reduce friction. Meibomian gland dysfunction (MGD) is the leading cause of dry eye disease and one of the most common ophthalmic problems worldwide. MGs are densely innervated and regulated by hormones and growth factors. However, since the polar and nonpolar lipids are produced through processes in MGs that are not completely understood, a relevant question has been raised: Would the altered systemic lipids metabolism affect the physiology and structure of MGs? This review introduces the recent update regarding the relationships between serum lipid and MGD in clinical and basic research while providing answers to this question. A causal relationship remains to be established; however, serum lipid level or dyslipidemia may be related to MGD directly or indirectly, or both. Further studies are warranted to establish the role of serum lipid level and meibocyte differentiation/maturation and lipid synthesis.
Collapse
|
28
|
Viitaja T, Raitanen JE, Hynynen A, Moilanen J, Svedström K, Paananen RO, Ekholm FS. On the importance of chain branching in tear film lipid layer wax and cholesteryl esters. Colloids Surf B Biointerfaces 2022; 214:112429. [PMID: 35278859 DOI: 10.1016/j.colsurfb.2022.112429] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 11/30/2022]
Abstract
The tear film lipid layer (TFLL) is important to the maintenance of ocular surface health. Surprisingly, information on the individual roles of the myriad of unique lipids found therein is limited. The most abundant lipid species are the wax esters (WE) and cholesteryl esters (CE), and, especially their branched analogs. The isolation of these lipid species from the TFLL has proved to be tedious, and as a result, insights on their biophysical profiles and role in the TFLL is currently lacking. Herein, we circumvent these issues by a total synthesis of the most abundant iso-methyl branched WEs and CEs found in the TFLL. Through a detailed characterization of the biophysical properties, by the use of Langmuir monolayer and wide-angle X-ray scattering techniques, we demonstrate that chain branching alters the behavior of these lipid species on multiple levels. Taken together, our results fill an important knowledge gap concerning the structure and function of the TFLL on the whole.
Collapse
Affiliation(s)
- Tuomo Viitaja
- Department of Chemistry, University of Helsinki, P.O. Box 55, Helsinki FI-00014, Finland; Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, Helsinki FI-00290, Finland
| | - Jan-Erik Raitanen
- Department of Chemistry, University of Helsinki, P.O. Box 55, Helsinki FI-00014, Finland
| | - Antti Hynynen
- Department of Chemistry, University of Helsinki, P.O. Box 55, Helsinki FI-00014, Finland
| | - Jukka Moilanen
- Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, Helsinki FI-00290, Finland
| | - Kirsi Svedström
- Department of Physics, University of Helsinki, P.O. Box 64, Helsinki FI-00014, Finland
| | - Riku O Paananen
- Department of Chemistry, University of Helsinki, P.O. Box 55, Helsinki FI-00014, Finland; Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, Helsinki FI-00290, Finland.
| | - Filip S Ekholm
- Department of Chemistry, University of Helsinki, P.O. Box 55, Helsinki FI-00014, Finland.
| |
Collapse
|
29
|
Asiedu K. Candidate Molecular Compounds as Potential Indicators for Meibomian Gland Dysfunction. Front Med (Lausanne) 2022; 9:873538. [PMID: 35685417 PMCID: PMC9170961 DOI: 10.3389/fmed.2022.873538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 04/08/2022] [Indexed: 11/16/2022] Open
Abstract
Meibomian gland dysfunction (MGD) is the leading cause of dry eye disease throughout the world. Studies have shown that several molecules in meibum, including but not limited to interleukins, amino acids, cadherins, eicosanoids, carbohydrates, and proteins, are altered in meibomian gland dysfunction compared with healthy normal controls. Some of these molecules such as antileukoproteinase, phospholipase A2, and lactoperoxidase also show differences in concentrations in tears between meibomian gland dysfunction and dry eye disease, further boosting hopes as candidate biomarkers. MGD is a complex condition, making it difficult to distinguish patients using single biomarkers. Therefore, multiple biomarkers forming a multiplex panel may be required. This review aims to describe molecules comprising lipids, proteins, and carbohydrates with the potential of serving various capacities as monitoring, predictive, diagnostic, and risk biomarkers for meibomian gland dysfunction.
Collapse
|
30
|
Biochemistry of human tear film: A review. Exp Eye Res 2022; 220:109101. [DOI: 10.1016/j.exer.2022.109101] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 04/18/2022] [Accepted: 04/26/2022] [Indexed: 12/13/2022]
|
31
|
Feng KM, Chung CH, Chen YH, Chien WC, Chien KH. Statin Use Is Associated With a Lower Risk of Blepharitis: A Population-Based Study. Front Med (Lausanne) 2022; 9:820119. [PMID: 35372440 PMCID: PMC8965040 DOI: 10.3389/fmed.2022.820119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
Background Blepharitis is a common eye disorder that may be overlooked by patients and clinical practitioners. The symptoms of blepharitis often manifest as irritation, a burning sensation, grittiness, and itchiness and may decrease visual acuity if not treated promptly. Meibomian gland dysfunction (MGD), a common cause of blepharitis, is believed to be associated with increased inflammatory marker levels that may disrupt the composition of lipids produced by the sebaceous glands in the eyelids and ultimately cause tear film instability. Methods This is a retrospective, population-based study using National Health Insurance Research Database (NHIRD) data from a 14-year period (2000–2015). Pearson chi-squared and Student's t-tests were used to assess the differences in categorical and continuous variables, respectively, between statin users and non-statin users. Univariate and multivariate Cox regression analyses were performed to calculate the hazard ratios (HRs) after adjusting for confounders. Kaplan-Meier analysis was used to assess the cumulative risk of blepharitis between the two cohorts. Results A total of 67,014 patients who used statins were enrolled as the study cohort, and 268,056 patients who did not use statins were enrolled as the comparison cohort. The incidence of blepharitis was 3.04% with statin treatment and 3.72% without statin treatment (p < 0.001). Patients who used statins had a lower risk of developing blepharitis [adjusted hazard ratio (aHR): 0.746, p < 0.001] than those who did not. In addition, diabetes mellitus (DM), hypertension, coronary heart disease (CHD), stroke, chalazion, rosacea, Sjogren syndrome, psoriasis and atopy were found to be possible risk factors for blepharitis. Conclusion Statin use can decrease the risk of developing blepharitis. However, further prospective studies are needed to evaluate statin treatment for various subtypes of blepharitis and to identify the associated mechanism.
Collapse
Affiliation(s)
- Kathy Ming Feng
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Chi-Hsiang Chung
- Department of Medical Research, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.,School of Public Health, National Defense Medical Center, Taipei, Taiwan.,Taiwanese Injury Prevention and Safety Promotion Association, Taipei, Taiwan
| | - Yi-Hao Chen
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Wu-Chien Chien
- Department of Medical Research, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.,School of Public Health, National Defense Medical Center, Taipei, Taiwan.,Taiwanese Injury Prevention and Safety Promotion Association, Taipei, Taiwan.,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Ke-Hung Chien
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| |
Collapse
|
32
|
Valencia E, García M, Fernández-Vega B, Pereiro R, Lobo L, González-Iglesias H. Targeted Analysis of Tears Revealed Specific Altered Metal Homeostasis in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2022; 63:10. [PMID: 35426907 PMCID: PMC9034717 DOI: 10.1167/iovs.63.4.10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Purpose Specific altered metal homeostasis has been investigated in the tear film of age-related macular degeneration (AMD) patients considering that metal dyshomeostasis contributes to the production of free radicals, inflammation, and apoptosis and results in conformational changes of proteins. Methods A multitargeted approach based on spectrophotometry and mass spectrometry techniques has been implemented to the multiplexed quantitation of lactoferrin (LF), S100 calcium binding protein A6 (S100A6), metallothionein 1A (MT1A), complement factor H (CFH), clusterin (CLU), amyloid precursor protein (APP), Mg, P, Na, Fe, Cu, Zn, and Ca, in the tear film from 60 subjects, 31 patients diagnosed with the dry form of AMD, and 29 healthy individuals Results Significant up-regulations of MT1A (1.9-fold) and S100A6 (1.4-fold) and down-regulations of LF (0.7-fold), Fe (0.6-fold), Mg (0.7-fold), and Cu (0.7-fold) were observed in AMD patients, when compared to control subjects. Of all the studied variables, only APP showed negative correlation with age in the AMD group. Also, positive correlations were observed for the variables Mg and Na, Cu and Mg, and P and Mg in both the AMD and control groups, whereas positive correlations were exclusively determined in the AMD group for Cu and LF, Na and Ca, and Mg and Ca. The panel constituted of MT1A, Na, and Mg predicts AMD disease in 73% of cases. Conclusions The different levels of target metals and (metallo-)proteins in the tear film suggest altered metal homeostasis in AMD patients. These observed pathophysiological changes may be related with the anomalous protein aggregation in the macula.
Collapse
Affiliation(s)
- Eva Valencia
- Ophtalmological Research Foundation, University Institute Fernández-Vega, University of Oviedo, Oviedo, Spain.,Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Oviedo, Spain
| | - Montserrat García
- Ophtalmological Research Foundation, University Institute Fernández-Vega, University of Oviedo, Oviedo, Spain.,Ophthalmological Institute Fernández-Vega, Oviedo, Spain
| | - Beatriz Fernández-Vega
- Ophtalmological Research Foundation, University Institute Fernández-Vega, University of Oviedo, Oviedo, Spain.,Ophthalmological Institute Fernández-Vega, Oviedo, Spain
| | - Rosario Pereiro
- Ophtalmological Research Foundation, University Institute Fernández-Vega, University of Oviedo, Oviedo, Spain.,Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Oviedo, Spain
| | - Lara Lobo
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Oviedo, Spain
| | - Héctor González-Iglesias
- Ophtalmological Research Foundation, University Institute Fernández-Vega, University of Oviedo, Oviedo, Spain.,Ophthalmological Institute Fernández-Vega, Oviedo, Spain
| |
Collapse
|
33
|
Acera A, Abad B, Pereiro X, Rodríguez FD, Ruzafa N, Duran JA, Vecino E. Comparative study of the lipid profile of tears and plasma enriched in growth factors. Exp Eye Res 2022; 219:109061. [DOI: 10.1016/j.exer.2022.109061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/19/2022] [Accepted: 03/30/2022] [Indexed: 01/05/2023]
|
34
|
Widjaja-Adhi MAK, Chao K, Golczak M. Mouse models in studies on the etiology of evaporative dry eye disease. Exp Eye Res 2022; 219:109072. [DOI: 10.1016/j.exer.2022.109072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 03/28/2022] [Accepted: 04/05/2022] [Indexed: 11/26/2022]
|
35
|
Mudgil P. Antimicrobial Tear Lipids in the Ocular Surface Defense. Front Cell Infect Microbiol 2022; 12:866900. [PMID: 35433501 PMCID: PMC9008483 DOI: 10.3389/fcimb.2022.866900] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/07/2022] [Indexed: 12/05/2022] Open
Abstract
The concept of antimicrobial lipids as effectors of innate host defense is an emerging field. There is limited knowledge on the antimicrobial role of lipids in the ocular environment. Tears act as first line of defense to protect the ocular surface from infections. Antimicrobial effects of tear lipids have been demonstrated using meibomian lipids that are the source of majority of lipids in tears. This article describes the knowledge available on the antimicrobial role of tear lipids at the ocular surface and the antimicrobial potential of various lipid classes present in tears that can contribute to antimicrobial protection of the eye. Like other mucosal secretions, tears contain many proteins and lipids with known antimicrobial effects. The antimicrobial defense of tears is far stronger than can be demonstrated by the effects of individual compounds many of which are present in low concentrations but synergistic and additive interactions between them provide substantial antimicrobial protection to the ocular surface. It is inferred that antimicrobial lipids play important role in innate defense of tears, and cooperative interactions between various antimicrobial lipids and proteins in tears provide a potent host defense mechanism that is effective against a broad spectrum of pathogens and renders self-sterilizing properties to tears for keeping the microbial load low at the ocular surface.
Collapse
|
36
|
Jun I, Kim S, Kim H, Kim SW, Ji YW, Kim KP, Lee TG, Seo KY. Evaluation of Meibum Lipid Composition According to Tear Interferometric Patterns: RRH: Meibum Composition According to Interferometric Patterns. Am J Ophthalmol 2022; 240:37-50. [PMID: 35227696 DOI: 10.1016/j.ajo.2022.02.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 02/09/2022] [Indexed: 11/17/2022]
Abstract
PURPOSE To determine the relationship between tear film interferometric patterns and properties of lipid, including rheological properties. DESIGN Prospective, cross-sectional laboratory investigation. METHOD This study included 105 subjects (94 dry eye patients and 11 normal participants). The subjects were divided into 3 categories (group 1, normal; group 2, thin; and group 3, irregular) according to interferometric patterns. According to tear interferometric patterns, ultra-performance liquid chromatography (LC) quadrupole-linear ion trap/mass spectrometry (MS)-based analysis was used to investigate lipid profiling of meibum. Rheological properties were examined by using a Langmuir-Blodgett trough with saline solution. RESULTS Normal subjects showed Pearl-like patterns, and dry eye patients showed either irregular or thin patterns. Group 2 tended to be the evaporative type, and group 3 tended to be the aqueous-deficient type. Lipid profiling using LC-MS identified 280 lipid species of 25 lipid classes. In the meibum of the patient groups, the content of cholesteryl esters and nonpolar lipids was lower than that in the normal group. However, the content of polar lipids such as sphingolipids and phospholipids in the patient groups was higher than that in the normal group. Rheological properties showed that the lift-off areas were comparable among the 3 groups and the surface tension was the highest in group 1, followed by group 3 and group 2. CONCLUSIONS The findings of this study suggest that tear interferometric patterns are associated with lipid profiling of meibum and its rheological properties. These results may contribute toward the development of new treatment modalities.
Collapse
Affiliation(s)
- Ikhyun Jun
- From the Institute of Vision Research (I.J, Y.W.J, K.Y.S), Department of Ophthalmology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemungu, Seoul 03722, South Korea; Corneal Dystrophy Research Institute, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemungu, Seoul 03722, South Korea
| | - Sehui Kim
- Department of Chemical and Biomolecular Engineering, Yonsei University (S.K, T.G.L), 50 Yonsei-ro, Seodaemungu, Seoul 03722, South Korea
| | - Hyoseon Kim
- Department of Applied Chemistry, Institute of Natural Science, Global Center for Pharmaceutical Ingredient Materials, Kyung Hee University (H.K, K.P.K), Yongin, South Korea; Department of Biomedical Science and Technology, Kyung Hee Medical Science Research Institute, Kyung Hee University, Seoul (H.K, K.P.K), South Korea
| | - Sun Woong Kim
- Department of Ophthalmology, Wonju Severance Christian Hospital, 20 Ilsan-ro, Wonju 26426, South Korea
| | - Yong Woo Ji
- From the Institute of Vision Research (I.J, Y.W.J, K.Y.S), Department of Ophthalmology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemungu, Seoul 03722, South Korea
| | - Kwang Pyo Kim
- Department of Applied Chemistry, Institute of Natural Science, Global Center for Pharmaceutical Ingredient Materials, Kyung Hee University (H.K, K.P.K), Yongin, South Korea; Department of Biomedical Science and Technology, Kyung Hee Medical Science Research Institute, Kyung Hee University, Seoul (H.K, K.P.K), South Korea
| | - Tai Gyu Lee
- Department of Chemical and Biomolecular Engineering, Yonsei University (S.K, T.G.L), 50 Yonsei-ro, Seodaemungu, Seoul 03722, South Korea
| | - Kyoung Yul Seo
- From the Institute of Vision Research (I.J, Y.W.J, K.Y.S), Department of Ophthalmology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemungu, Seoul 03722, South Korea
| |
Collapse
|
37
|
Uptake and release of polyhexamethylene biguanide (PHMB) from hydrogel and silicone hydrogel contact lenses using a radiolabel methodology. Cont Lens Anterior Eye 2022; 45:101575. [DOI: 10.1016/j.clae.2022.101575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/11/2022] [Accepted: 01/26/2022] [Indexed: 11/19/2022]
|
38
|
Biophysical properties of tear film lipid layer II. Polymorphism of FAHFA. Biophys J 2022; 121:451-458. [PMID: 34968427 PMCID: PMC8822609 DOI: 10.1016/j.bpj.2021.12.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 12/04/2021] [Accepted: 12/22/2021] [Indexed: 02/03/2023] Open
Abstract
Fatty acid esters of hydroxy fatty acids (FAHFAs) are a newly discovered class of endogenous lipids that consist of two acyl chains connected through a single ester bond. Being a unique species of FAHFAs, (O-acyl)-ω-hydroxy fatty acids (OAHFAs) differ from other FAHFAs in that their hydroxy fatty acid backbones are ultralong and their hydroxy esterification is believed to be solely at the terminal (ω-) position. Only in recent years with technological advances in lipidomics have OAHFAs been identified as an important component of the tear film lipid layer (TFLL). It was found that OAHFAs account for approximately 4 mol% of the total lipids and 20 mol% of the polar lipids in the TFLL. However, their biophysical function and contribution to the TFLL is still poorly understood. Here we studied the molecular biophysical mechanisms of OAHFAs using palmitic-acid-9-hydroxy-stearic-acid (PAHSA) as a model. PAHSA and OAHFAs share key structural similarities that could result in comparable biophysical properties and molecular mechanisms. With combined biophysical experiments, atomic force microscopy observations, and all-atom molecular dynamics simulations, we found that the biophysical properties of a dynamic PAHSA monolayer under physiologically relevant conditions depend on a balance between kinetics and thermal relaxation. PAHSA molecules at the air-water surface demonstrate unique polymorphic behaviors, which can be explained by configurational transitions of the molecules under various lateral pressures. These findings could have novel implications in understanding biophysical functions that FAHFAs, in general, or OAHFAs, specifically, play in the TFLL.
Collapse
|
39
|
Xu X, Li G, Zuo YY. Biophysical properties of tear film lipid layer I. Surface tension and surface rheology. Biophys J 2022; 121:439-450. [PMID: 34958775 PMCID: PMC8822608 DOI: 10.1016/j.bpj.2021.12.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 12/04/2021] [Accepted: 12/22/2021] [Indexed: 02/03/2023] Open
Abstract
Tear film lipid layer (TFLL) is the outmost layer of the tear film. It plays a crucial role in stabilizing the tear film by reducing surface tension and retarding evaporation of the aqueous layer. Dysfunction of the TFLL leads to dysfunctional tear syndrome, with dry eye disease (DED) being the most prevalent eye disease, affecting 10%-30% of the world population. To date, except for treatments alleviating dry eye symptoms, effective therapeutic interventions in treating DED are still lacking. Therefore, there is an urgent need to understand the biophysical properties of the TFLL with the long-term goal to develop translational solutions in effectively managing DED. Here, we studied the composition-function correlations of an artificial TFLL, under physiologically relevant conditions, using a novel experimental methodology called constrained drop surfactometry. This artificial TFLL was composed of 40% behenyl oleate and 40% cholesteryl oleate, representing the most abundant wax ester and cholesteryl ester in the natural TFLL, respectively, and 15% phosphatidylcholine and 5% palmitic-acid-9-hydroxy-stearic-acid (PAHSA), which represent the two predominant polar lipid classes in the natural TFLL. Our study suggests that the major biophysical function of phospholipids in the TFLL is to reduce the surface tension, whereas the primary function of PAHSA is to optimize the rheological properties of the TFLL. These findings have novel implications in better understanding the physiological and biophysical functions of the TFLL and may offer new translational insight to the treatment of DED.
Collapse
Affiliation(s)
- Xiaojie Xu
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu
| | - Guangle Li
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu
| | - Yi Y. Zuo
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu,Department of Pediatrics, John A. Burns School of Medicine, University of Hawaii, Honolulu,Corresponding author
| |
Collapse
|
40
|
Eftimov P, Yokoi N, Georgiev GA. Surface Chemistry Study of the Interactions of Sesame Oil with Meibomian Films. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27020464. [PMID: 35056778 PMCID: PMC8777812 DOI: 10.3390/molecules27020464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 11/16/2022]
Abstract
A possible approach for the treatment of meibomian gland disease (MGD) can be the supplementation of meibomian gland secretion (MGS) with nonpolar lipids (NPL) rich plant oils. Sesame oil (SO), approximately equal in monounsaturated fat (oleic acid, 40% of total) and polyunsaturated fat (linoleic acid, 42% of total), has shown multiple health benefits due to its anti-inflammatory and antioxidant effects. Thus, the interactions between SO and MGS in surface layers deserve further study. Therefore, pseudobinary films were formed with controlled MGS/SO molar ratios (0%, 10%, 30%, 50%, and 100% SO) at the air/water surface of the Langmuir trough over phosphate buffered saline (pH 7.4) subphase. Surface pressure (π)-area (A) isotherms and Brewster angle microscopy observations showed nonideal interactions where SO aggregates with MGS and complements the NPL stratum of the meibomian layers. The analysis of stress relaxation transients with Kohlrausch–Williams–Watts equation revealed that the supplementation of fixed amount of MGS with excess lipids via SO altered the dilatational elasticity of the films as reflected by the increase of the exponent β. Thus, SO with its unique combination of high oxidative stability and abundance of long polyunsaturated acyl chains might be a useful supplement to MGS layers.
Collapse
Affiliation(s)
- Petar Eftimov
- Department of Cytology, Histology and Embryology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria;
| | - Norihiko Yokoi
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
| | - Georgi As. Georgiev
- Faculty of Physics, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria
- Correspondence: ; Tel.: +359-2-962-3157
| |
Collapse
|
41
|
Human meibum and tear film derived cholesteryl and wax esters in meibomian gland dysfunction and tear film structure. Ocul Surf 2022; 23:12-23. [PMID: 34774809 PMCID: PMC9875797 DOI: 10.1016/j.jtos.2021.10.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 02/07/2023]
Abstract
PURPOSE This study evaluated the presence and roles of cholesteryl esters (CEs) and wax esters (WEs) from human tear film and meibum in meibomian gland dysfunction (MGD). METHODS Out of 195 enrolled subjects, 164 and 179 subjects provided tear and meibum samples, respectively. Subjects were classified into normal, asymptomatic MGD, MGD, and mixed (MGD & aqueous deficient). The precorneal tear film (PCTF) thinning rate (evaporation) was measured using optical coherence tomography. Lipids extracted from tear and meibum samples were infused into a SCIEX 5600 TripleTOF mass spectrometer. CE and WE intensities quantified with Analyst 1.7 TF and LipidView 1.3 were compared across disease groups in MetaboAnalyst 5.0 and correlated with PCTF thinning rates. RESULTS The numbers of unique CEs and WEs identified in the samples were 125 and 86, respectively. Unsupervised Principal Component (PC) analysis and supervised Partial Least Square Discriminant analysis exhibited little separation among groups for both CEs and WEs in tears and meibum. Spearman's correlation analyses showed no association between either the first or second PC scores with PCTF thinning rates. CONCLUSION The abundances of human PCTF and meibum-derived CEs and WEs were independent of MGD disease status and PCTF thinning (evaporation). CEs and WEs alterations do not contribute to alterations in tear film dynamics in MGD, such as has been demonstrated by the (O-acyl) ω-hydroxy fatty acids (OAHFAs).
Collapse
|
42
|
Nanomedicine for Ocular Drug Delivery. Nanomedicine (Lond) 2022. [DOI: 10.1007/978-981-13-9374-7_32-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
|
43
|
Bai Y, Ngo W, Khanal S, Nichols JJ. Characterization of the thickness of the Tear Film Lipid Layer in Meibomian Gland Dysfunction using high resolution optical microscopy. Ocul Surf 2021; 24:34-39. [PMID: 34968765 DOI: 10.1016/j.jtos.2021.12.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 12/21/2021] [Accepted: 12/23/2021] [Indexed: 12/19/2022]
Abstract
PURPOSE To evaluate the thickness of the tear film lipid layer (TFLL) in meibomian gland dysfunction (MGD) using a high-resolution optical microscope. METHODS The Ocular Surface Disease Index (OSDI) and meibum grade score (MGS) were used to classify 190 subjects into four groups: normal (OSDI<13 and MGS<10), mixed (OSDI≥13 and MGS<10), asymptomatic MGD (OSDI<13 and MGS≥10), and MGD (OSDI≥13 and MGS≥10). The high-resolution optical microscope was used to capture TFLL images in vivo. The histograms of TFLL thickness were analyzed and curve-fitted using probability density functions (PDFs). RESULTS There were three obvious peaks in the distributions of TFLL across the groups. From the curve-fitting process, the main outcomes are displayed according to each Gaussian function with the position of peak (μ) and the summed percentage within the range of standard deviation (σ). The normal group had distribution as follows: 33.3 ± 0.005 nm, 26%; 53.9 ± 0.019 nm, 40%; 79.4 ± 0.064 nm, 12%. The mixed group had a distribution as follows: 33.8 ± 0.004 nm, 32%; 53.1 ± 0.115 nm, 21%; 71.7 ± 0.232 nm, 27%. The asymptomatic MGD group had a distribution as follows: 33.5 ± 0.004 nm, 20%; 49.2 ± 0.041 nm, 25%; 62.9 ± 0.063 nm, 47%. The MGD group had a distribution as follows: 34.3 ± 0.004 nm, 34%; 53.7 ± 0.022 nm, 28%; 74.9 ± 0.060 nm, 16%. CONCLUSIONS The MGD and mixed groups had the largest percentages of TFLL thicknesses fall within the thinnest modes (peak 34.3 and 33.8 nm, respectively). These data show that measures of central tendency (e.g., averages, medians) do not fully appreciate the variable distributions of TFLL across disease spectra.
Collapse
Affiliation(s)
- Yuqiang Bai
- Department of Optometry and Vision Science, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - William Ngo
- Centre for Ocular Research & Education, School of Optometry & Vision Science, University of Waterloo, Waterloo, Ontario, Canada; Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
| | - Safal Khanal
- Department of Optometry and Vision Science, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jason J Nichols
- Department of Optometry and Vision Science, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA.
| |
Collapse
|
44
|
Eftimov P, Ewurum A, Ankem A, Borchman D, Georgiev GA. Correlations between bulk and surface properties of meibomian lipids with alteration of wax-to-sterol esters content. Chem Phys Lipids 2021; 242:105163. [PMID: 34864017 DOI: 10.1016/j.chemphyslip.2021.105163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 11/03/2022]
Abstract
In a recent study (Ewurum et al., 2021), wax (WE) and sterol esters (CE) from human meibum secretions (MGS) were separated and reconstituted with controlled WE/CE ratios (0%, 20%, 30%, 40%, 50%, 75% and 100% CE weight fractions). It was found that the alterations in the CE content of WE/CE mixtures modified the hydrocarbon chain conformation and packing of the mixture. A major question that emerges is whether the spectroscopic packing parameters determined for bulk meibum translate to a change in the performance of meibomian layers at the air/water interface, as it is the surface film functionality that is crucial for the performance of MGS at the ocular surface. The study of human meibum films with Langmuir surface balance was performed to access the surface properties at blink-like deformations of the film area. Surface pressure (π)-area (A) isocycles and stress relaxations were used to assess the layer's reorganization during area cycling and dilatational elasticity, respectively. The morphology of the films was monitored by Brewster angle microscopy. It was found that the increased order and chain melting temperature of the bulk samples correlated with a raise in the maximum surface pressure attained at minimal surface area and in the transient dilatational modulus of the meibomian layers. Such correlations may allow for development of an improved understanding between the bulk and surface properties of human meibum and of other natural and synthetic tear lipid films.
Collapse
Affiliation(s)
- Petar Eftimov
- Department of Cytology, Histology and Embryology, Faculty of Biology, St. Kliment Ohridski University of Sofia, Bulgaria
| | - Anthony Ewurum
- Department of Chemistry, University of Louisville, Louisville, KY, USA
| | - Akhila Ankem
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY, USA
| | - Douglas Borchman
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY, USA
| | - Georgi As Georgiev
- iBB - Institute for Bioengineering and Biosciences, Interdisciplinary Complex, IST, University of Lisbon, 1649-004 Lisbon, Portugal.
| |
Collapse
|
45
|
Badian RA, Utheim TP, Chen X, Utheim ØA, Ræder S, Ystenæs AE, Aakre BM, Sundling V. Meibomian gland dysfunction is highly prevalent among first-time visitors at a Norwegian dry eye specialist clinic. Sci Rep 2021; 11:23412. [PMID: 34862425 PMCID: PMC8642422 DOI: 10.1038/s41598-021-02738-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 11/22/2021] [Indexed: 11/08/2022] Open
Abstract
To investigate the prevalence of meibomian gland dysfunction (MGD) in patients presenting with subjective dry eye-related symptoms at their first-time consultation in a Norwegian specialized ocular surface clinic. Additionally, to explore the accuracy of the ocular surface disease index score (OSDI) as an extensively applied tool to assess the severity of dry eye symptoms and MGD diagnosis. Patients with subjective dry eye-related complaints (n = 900) attending the clinic for the first time, from 2012 to 2016, were included in the study. At the baseline, patients completed the OSDI questionnaire. Subsequently, objective clinical tests, including fluorescein break-up time (FBUT), Schirmer-I test, ocular surface staining (OSS), and meibomian gland function assessment using gland expressibility and meibum quality were performed. The association between MGD and its severity in relation to symptom severity defined by OSDI-score was examined. MGD was found in 93.8% of the study group. MGD prevalence was not significantly different between groups based on age (p = 0.302) or sex (p = 0.079). There was a significant association between severity of MGD and dry eye-related symptoms (p = 0.014). OSS was significantly higher in patients with severe symptoms (p = 0.031). Sensitivity and specificity of positive symptom-score (OSDI ≥ 13) for disclosing MGD were 85.5% and 30.4%, respectively. MGD was highly prevalent, not associated with age and sex. OSDI ≥ 13 had high sensitivity and high positive predictive value (PPV), but low specificity and negative predictive value (NPV) for disclosing MGD. This underscores the importance of meibomian gland assessment in patients with dry eye-related symptoms.
Collapse
Affiliation(s)
- Reza A Badian
- National Centre for Optics, Vision and Eye Care, Department of Optometry, Radiography and Lighting Design, Faculty of Health and Social Sciences, University of South-Eastern Norway, Notodden, Norway.
| | - Tor Paaske Utheim
- National Centre for Optics, Vision and Eye Care, Department of Optometry, Radiography and Lighting Design, Faculty of Health and Social Sciences, University of South-Eastern Norway, Notodden, Norway
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway
- Department of Ophthalmology, Stavanger University Hospital, Stavanger, Norway
- The Norwegian Dry Eye Clinic, Oslo, Norway
- Department of Ophthalmology, Sørlandet Hospital Arendal, Arendal, Norway
- Department of Ophthalmology, Drammen Hospital, Drammen, Norway
| | - Xiangjun Chen
- National Centre for Optics, Vision and Eye Care, Department of Optometry, Radiography and Lighting Design, Faculty of Health and Social Sciences, University of South-Eastern Norway, Notodden, Norway
- The Norwegian Dry Eye Clinic, Oslo, Norway
- Department of Ophthalmology, Sørlandet Hospital Arendal, Arendal, Norway
- Department of Ophthalmology, Drammen Hospital, Drammen, Norway
| | - Øygunn Aass Utheim
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway
- The Norwegian Dry Eye Clinic, Oslo, Norway
| | - Sten Ræder
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- The Norwegian Dry Eye Clinic, Oslo, Norway
| | - Ann Elisabeth Ystenæs
- National Centre for Optics, Vision and Eye Care, Department of Optometry, Radiography and Lighting Design, Faculty of Health and Social Sciences, University of South-Eastern Norway, Notodden, Norway
| | - Bente Monica Aakre
- National Centre for Optics, Vision and Eye Care, Department of Optometry, Radiography and Lighting Design, Faculty of Health and Social Sciences, University of South-Eastern Norway, Notodden, Norway
| | - Vibeke Sundling
- National Centre for Optics, Vision and Eye Care, Department of Optometry, Radiography and Lighting Design, Faculty of Health and Social Sciences, University of South-Eastern Norway, Notodden, Norway
| |
Collapse
|
46
|
Sahu DK, Pradhan D, Biswasroy P, Kar B, Ghosh G, Rath G. Recent trends in nanocarrier based approach in the management of dry eye disease. J Drug Deliv Sci Technol 2021. [DOI: 10.1016/j.jddst.2021.102868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
47
|
Expression of Acyl-CoA wax-alcohol acyltransferase 2 (AWAT2) by human and rabbit meibomian glands and meibocytes. Ocul Surf 2021; 23:60-70. [PMID: 34838721 PMCID: PMC10393063 DOI: 10.1016/j.jtos.2021.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 11/18/2021] [Accepted: 11/20/2021] [Indexed: 11/22/2022]
Abstract
PURPOSE Previously, we showed that Acyl-CoA wax-alcohol acyltransferase 2 (AWAT2), an essential enzyme required for meibum wax ester synthesis, was not expressed by immortalized human meibomian gland epithelial cells (hMGEC) in culture. To begin to understand the mechanisms controlling AWAT2 expression, we have analyzed its expression in human and rabbit meibomian glands and cultured meibocytes. METHODS Rabbit meibocyte progenitor cells (rMPC) were first grown in Cnt-BM.1 basal medium (Cellntec) supplemented with rhEGF, FGF10, and ROCK inhibitor (Y-27632 dihydrochloride), and then passed at 70-80% confluency with Accutase. Differentiation of rMPC to meibocytes (rMC) was induced by removal of Y-27632 and addition of 1 mM calcium with and without PPARγ agonists. RNA from the tissue, primary, passaged rMPC and differentiated rMC were obtained for AWAT2 qPCR analysis. Proteins and cells were evaluated for western blotting and neutral lipid synthesis, respectively. For comparison, human meibomian glands were separated for RNA and protein analysis. hMGEC was cultured to collect RNA and protein. RESULTS Rabbit rMPCs were successfully grown, passaged, and differentiated, showing a significant increase in lipid droplet accumulation. AWAT2 RNA was highly expressed in tissue but showed a -16.9 log2 fold decrease in primary and passaged rMPCs and was not induced by differentiation to rMC. By comparison, human meibomian glands showed high expression of AWAT2, and hMGEC expressed non-detectable levels of AWAT2 transcripts or protein. CONCLUSIONS AWAT2 expression is lost in cultured rMPC and rMC suggesting that cells in culture do not undergo complete meibocyte differentiation and require yet to be identified culture conditions.
Collapse
|
48
|
Gao Y, Qi Y, Huang Y, Li X, Zhou L, Zhao S. Lipidomics Analysis of the Tears in the Patients Receiving LASIK, FS-LASIK, or SBK Surgery. Front Med (Lausanne) 2021; 8:731462. [PMID: 34778293 PMCID: PMC8579130 DOI: 10.3389/fmed.2021.731462] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 09/24/2021] [Indexed: 01/17/2023] Open
Abstract
Purpose: Tear film lipid layer (TFLL) plays a vital role in maintaining the tear film stability and, thus, the lipid composition of the tears could greatly affect the physiological function and biophysical integrity of the tear film. The objective of this study is to assess the tear lipid composition of the patients receiving laser-assisted in situ keratomileusis (LASIK), femtosecond LASIK (FS-LASIK), or sub-Bowman's keratomileusis (SBK) surgery preoperatively and postoperatively. Methods: Tear samples were collected from the left eye of the patient who receiving LASIK (n = 10), FS-LASIK (n = 10), or SBK (n = 10) surgery in week 0, week 1, week 4, and week 52. A rapid direct injection shotgun lipidomics workflow, MS/MSALL (<2 min/sample), was applied to examine the tear lipidome. Results: In week 52, the SBK group demonstrated a similar lipidome profile compared to week 0, while the FS-LASIK and LASIK groups shifted away from week 0. Two lipids, ganglioside (GD3) 27:4 and triacylglycerol (TAG) 59:3, were found to be associated with the lipidome changes preoperatively and postoperatively. No statistical significance was found in the overall lipid classes from the FS-LASIK group. The LASIK group showed significant alteration in the phospholipid and sphingolipid over time, while the SBK group demonstrated a significant difference in the (O-acyl)-ω-hydroxy fatty acid (OAHFA) and phospholipid. Conclusion: LASIK showed the greatest impact on the tear lipidome changes over time, while SBK demonstrated minimal impact among the three types of refractive surgeries after 1 year.
Collapse
Affiliation(s)
- Yan Gao
- Ocular Proteomics Platform, Singapore Eye Research Institute, Singapore, Singapore
| | - Yuanyuan Qi
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Yue Huang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Xiaorong Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Lei Zhou
- Ocular Proteomics Platform, Singapore Eye Research Institute, Singapore, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Ophthalmology and Visual Sciences Academia Clinical Program, Duke-National University of Singapore Medical School, Singapore, Singapore
| | - Shaozhen Zhao
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| |
Collapse
|
49
|
Suzuki T, Kitazawa K, Cho Y, Yoshida M, Okumura T, Sato A, Kinoshita S. Alteration in meibum lipid composition and subjective symptoms due to aging and meibomian gland dysfunction. Ocul Surf 2021; 26:310-317. [PMID: 34666148 DOI: 10.1016/j.jtos.2021.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/06/2021] [Accepted: 10/15/2021] [Indexed: 12/14/2022]
Abstract
PURPOSE To investigate the alteration in lipid composition of meibum, objective clinical signs, and subjective symptoms associated with aging and meibomian gland (MG) dysfunction (MGD). METHODS In 10 MGD patients [4 males/6 females, mean age: 65.6 ± 7.9 years (range: 50-79 years)] and 24 healthy volunteer subjects [young subjects: 6 males/6 females, mean age: 25.7 ± 3.8 years (range: 20-35 years), elderly subjects: 6 males/6 females, mean age: 58.4 ± 7.5 years (range: 50-79 years)], three objective clinical signs were evaluated: MG orifice obstruction, meibum score, and tear film lipid layer interference pattern. Subjective symptoms were analyzed via a 15-item questionnaire. After careful collection of meibum samples, comprehensive lipid analysis was performed via liquid chromatography-mass spectrometry. Data was analyzed via JMP® ver. 13 (SAS Institute, Inc., Cary, NC) statistical analysis software. RESULTS In the MGD patients and elderly subjects, there was a significant decrease in non-polar lipids such as cholesterol esters (ChEs), while a significant increase in polar lipids [cholesterol (Ch), (O-acyl)-ω-hydroxy fatty acid (OAHFA), and free fatty acid (FA)] in total lipids (Tukey-Kramer test: p < 0.05). Triglyceride was significantly increased only in MGD patients (p < 0.05). Symptom scores representative of vision quality (i.e., blurred vision/haziness) were significantly negatively-correlated with the ratio of the non-polar lipid ChE, while significantly positively correlated with the polar lipids Ch, OAHFA, and FA (Spearman's rank correlation coefficient: p < 0.05). CONCLUSIONS Our findings revealed that both MGD and aging affect the composition ratio of major meibum lipids, resulting in the appearance of subjective symptoms.
Collapse
Affiliation(s)
- Tomo Suzuki
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan; Department of Ophthalmology, Kyoto City Hospital Organization, Kyoto, Japan.
| | - Koji Kitazawa
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yuko Cho
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan; Department of Ophthalmology, Kyoto City Hospital Organization, Kyoto, Japan
| | - Masataka Yoshida
- Research and Development Headquarters, Lion Corporation, Tokyo, Japan
| | - Takashi Okumura
- Research and Development Headquarters, Lion Corporation, Tokyo, Japan
| | - Atsushi Sato
- Research and Development Headquarters, Lion Corporation, Tokyo, Japan
| | - Shigeru Kinoshita
- Department of Frontier Medical Science and Technology for Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| |
Collapse
|
50
|
Mussi N, Haque W, Robertson DM. The Association Between Risk Factors for Metabolic Syndrome and Meibomian Gland Disease in a Dry Eye Cohort. Clin Ophthalmol 2021; 15:3821-3832. [PMID: 34539177 PMCID: PMC8445099 DOI: 10.2147/opth.s322461] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 07/22/2021] [Indexed: 01/02/2023] Open
Abstract
Purpose Risk factors for metabolic syndrome include abdominal obesity, insulin resistance, hypertension, high triglycerides and/or low high-density lipoprotein cholesterol, and hyperglycemia. Risk factors for metabolic syndrome have been associated with dry eye disease; however, their association with meibomian gland disease (MGD), a subtype of dry eye, is unclear. In the present study, we investigated risk factors for metabolic syndrome in a dry eye cohort with and without MGD. Methods This retrospective case-control study evaluated electronic medical records at a major urban outpatient medical center to identify patients with a known diagnosis of dry eye disease with and without MGD. Males and females were matched for age, smoking status, race, ethnicity, and body mass index (BMI). Patient demographics, anthropometric measurements, medical history, clinical findings, and serologies were analyzed. A diagnosis of MGD was based on clinical signs noted in the medical record. Results MGD was not associated with BMI, smoking, type 2 diabetes mellitus, hypertension or hyperlipidemia in this dry eye cohort. MGD was associated with male sex and increasing age. While increasing age was weakly correlated with decreased low density lipoprotein cholesterol and non-high density lipoprotein cholesterol, serum lipid levels were not associated with MGD. Conclusion Importantly, we found that risk factors for metabolic syndrome are not specifically associated with an increase in MGD when compared to non-MGD dry eye subjects. While risk factors for metabolic syndrome are associated with dry eye disease, they likely reflect a chronic systemic state of low-grade inflammation that negatively impacts the function of both lacrimal and meibomian glands.
Collapse
Affiliation(s)
- Natalia Mussi
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Waqas Haque
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Danielle M Robertson
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| |
Collapse
|