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Gary AA, Prislovsky A, Tovar A, Locatelli E, Felix ER, Stephenson D, Chalfant CE, Lai J, Kim C, Mandal N, Galor A. Lipids from ocular meibum and tears may serve as biomarkers for depression and post-traumatic stress disorder. Clin Exp Ophthalmol 2024; 52:516-527. [PMID: 38146655 PMCID: PMC11199378 DOI: 10.1111/ceo.14343] [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: 08/18/2023] [Revised: 11/14/2023] [Accepted: 12/01/2023] [Indexed: 12/27/2023]
Abstract
BACKGROUND There is a need to develop biomarkers for diagnosis and prediction of treatment responses in depression and post-traumatic stress disorder (PTSD). METHODS Cross-sectional study examining correlations between tear inflammatory proteins, meibum and tear sphingolipids, and symptoms of depression and PTSD-associated anxiety. Ninety individuals filled depression (Patient Health Questionnaire 9, PHQ-9) and PTSD-associated anxiety (PTSD Checklist-Military Version, PCL-M) questionnaires. In 40 patients, a multiplex assay system was used to quantify 23 inflammatory proteins in tears. In a separate group of 50 individuals, liquid chromatography-mass spectrometry was performed on meibum and tears to quantify 34 species of sphingolipids, encompassing ceramides, monohexosyl ceramides and sphingomyelins. RESULTS The mean age of the population was 59.4 ± 11.0 years; 89.0% self-identified as male, 34.4% as White, 64.4% as Black, and 16.7% as Hispanic. The mean PHQ-9 score was 11.1 ± 7.6, and the mean PCL-M score was 44.3 ± 19.1. Symptoms of depression and PTSD-associated anxiety were highly correlated (ρ =0.75, p < 0.001). Both PHQ9 and PCL-M scores negatively correlated with multiple sphingolipid species in meibum and tears. In multivariable models, meibum Monohexosyl Ceramide 26:0 (pmol), tear Ceramide 16:0 (mol%), meibum Monohexosyl Ceramide 16:0 (mol%), and tear Ceramide 26:1 (mol%) remained associated with depression and meibum Monohexosyl Ceramide 16:0 (mol%), meibum Monohexosyl Ceramide 26:0 (pmol), tear Sphingomyelin 20:0 (mol%), and tear Sphingosine-1-Phosphate (mol%) remained associated with PTSD-associated anxiety. CONCLUSIONS Certain meibum and tear sphingolipid species were related to mental health indices. These interactions present opportunities for innovative diagnostic and therapeutic approaches for mental health disorders.
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Affiliation(s)
- Ashlyn A. Gary
- Miller School of Medicine, University of Miami, Miami, FL, USA
| | | | - Arianna Tovar
- Surgical Services, Miami Veterans Affairs Medical Center, Miami, FL, USA
| | - Elyana Locatelli
- Surgical Services, Miami Veterans Affairs Medical Center, Miami, FL, USA
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
| | - Elizabeth R. Felix
- Research Service, Miami Veterans Affairs Medical Center, Miami, FL, USA
- Department of Physical Medicine & Rehabilitation, University of Miami, Miami, FL, USA
| | - Daniel Stephenson
- Departments of Medicine and Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Charles E. Chalfant
- Departments of Medicine and Cell Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - James Lai
- Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Colin Kim
- Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Nawajes Mandal
- Memphis VA Medical Center, Memphis, TN, USA
- Depts. of Ophthalmology, Anatomy and Neurobiology and Pharmaceutical Sciences, University of Tennessee Health Sciences Center, Hamilton Eye Institute, Memphis, TN, USA
| | - Anat Galor
- Surgical Services, Miami Veterans Affairs Medical Center, Miami, FL, USA
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
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Garcia-Queiruga J, Pena-Verdeal H, Sabucedo-Villamarin B, Paz-Tarrio M, Guitian-Fernandez E, Garcia-Resua C, Yebra-Pimentel E, Giraldez MJ. Meibum Lipidomic Analysis in Evaporative Dry Eye Subjects. Int J Mol Sci 2024; 25:4782. [PMID: 38731998 PMCID: PMC11083861 DOI: 10.3390/ijms25094782] [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: 03/26/2024] [Revised: 04/23/2024] [Accepted: 04/25/2024] [Indexed: 05/13/2024] Open
Abstract
Meibomian Glands (MG) are sebaceous glands responsible for the production of meibum, the main component of the Tear Film Lipid Layer (TFLL). The TFLL facilitates the spread of the tear film over the ocular surface, provides stability and reduces tear evaporation. Alterations in meibum composition lead to different ocular alterations like Meibomian Gland Dysfunction (MGD) and subsequent Evaporative Dry Eye (EDE). The aim of the present study was to investigate the composition and abundance of meibum lipids and their relationship with eyelid margin abnormalities, lipid layer patterns and MG status. The study utilizes a lipidomic approach to identify and quantify lipids in meibum samples using an Elute UHPLC system. This system considered all four dimensions (mass/charge, retention time, ion mobility and intensity) to provide the accurate identification of lipid species. Samples were categorized as healthy or low/no signs of alteration (group 1) or severe signs of alteration or EDE/MGD (group 2). The current investigation found differences in Variable Importance in Projection lipid abundance between both groups for the MGD signs studied. Changes in meibum composition occur and are related to higher scores in eyelid margin hyperaemia, eyelid margin irregularity, MG orifice plugging, MG loss and lipid layer pattern.
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Affiliation(s)
- Jacobo Garcia-Queiruga
- GI-2092 Optometry, Departamento de Física Aplicada, Facultad de Óptica y Optometría, Universidade de Santiago de Compostela, Campus Vida s/n, 15701 Santiago de Compostela, Spain; (J.G.-Q.); (H.P.-V.); (B.S.-V.); (C.G.-R.); (E.Y.-P.)
- AC-24 Optometry, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Travesía da Choupana, 15701 Santiago de Compostela, Spain
| | - Hugo Pena-Verdeal
- GI-2092 Optometry, Departamento de Física Aplicada, Facultad de Óptica y Optometría, Universidade de Santiago de Compostela, Campus Vida s/n, 15701 Santiago de Compostela, Spain; (J.G.-Q.); (H.P.-V.); (B.S.-V.); (C.G.-R.); (E.Y.-P.)
- AC-24 Optometry, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Travesía da Choupana, 15701 Santiago de Compostela, Spain
| | - Belen Sabucedo-Villamarin
- GI-2092 Optometry, Departamento de Física Aplicada, Facultad de Óptica y Optometría, Universidade de Santiago de Compostela, Campus Vida s/n, 15701 Santiago de Compostela, Spain; (J.G.-Q.); (H.P.-V.); (B.S.-V.); (C.G.-R.); (E.Y.-P.)
| | - Monica Paz-Tarrio
- Mass Spectrometry and Proteomic Unit, Área de Infraestruturas de Investigación, Universidade de Santiago de Compostela, Campus Vida s/n, 15701 Santiago de Compostela, Spain; (M.P.-T.); (E.G.-F.)
| | - Esteban Guitian-Fernandez
- Mass Spectrometry and Proteomic Unit, Área de Infraestruturas de Investigación, Universidade de Santiago de Compostela, Campus Vida s/n, 15701 Santiago de Compostela, Spain; (M.P.-T.); (E.G.-F.)
| | - Carlos Garcia-Resua
- GI-2092 Optometry, Departamento de Física Aplicada, Facultad de Óptica y Optometría, Universidade de Santiago de Compostela, Campus Vida s/n, 15701 Santiago de Compostela, Spain; (J.G.-Q.); (H.P.-V.); (B.S.-V.); (C.G.-R.); (E.Y.-P.)
- AC-24 Optometry, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Travesía da Choupana, 15701 Santiago de Compostela, Spain
| | - Eva Yebra-Pimentel
- GI-2092 Optometry, Departamento de Física Aplicada, Facultad de Óptica y Optometría, Universidade de Santiago de Compostela, Campus Vida s/n, 15701 Santiago de Compostela, Spain; (J.G.-Q.); (H.P.-V.); (B.S.-V.); (C.G.-R.); (E.Y.-P.)
- AC-24 Optometry, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Travesía da Choupana, 15701 Santiago de Compostela, Spain
| | - Maria J. Giraldez
- GI-2092 Optometry, Departamento de Física Aplicada, Facultad de Óptica y Optometría, Universidade de Santiago de Compostela, Campus Vida s/n, 15701 Santiago de Compostela, Spain; (J.G.-Q.); (H.P.-V.); (B.S.-V.); (C.G.-R.); (E.Y.-P.)
- AC-24 Optometry, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Travesía da Choupana, 15701 Santiago de Compostela, Spain
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3
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Sheppard JD, Nichols KK. Dry Eye Disease Associated with Meibomian Gland Dysfunction: Focus on Tear Film Characteristics and the Therapeutic Landscape. Ophthalmol Ther 2023; 12:1397-1418. [PMID: 36856980 PMCID: PMC10164226 DOI: 10.1007/s40123-023-00669-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 01/27/2023] [Indexed: 03/02/2023] Open
Abstract
Meibomian gland dysfunction (MGD) is highly prevalent and is the leading cause of evaporative dry eye disease (DED). MGD is characterized by a reduction in meibum secretion and/or a change in meibum composition that results in the disruption of the tear film lipid layer and an increase in the tear film evaporation rate. Excessive evaporation causes tear film instability, desiccation, tear hyperosmolarity, inflammation, and apoptosis of ocular surface cells, resulting in a continuous cycle of DED. The primary treatment goal for DED associated with MGD is to restore the tear film lipid layer and decrease evaporation, thereby reducing ocular signs and symptoms. The management of MGD includes home care options (eyelid hygiene, warming eye masks, ocular lubricants) and office-based treatments (manual expression, microblepharoexfoliation, thermal pulsation, intense pulsed light, intraductal probing). Topical ophthalmic prescription medications attempt to alter various factors that may contribute to DED (e.g., inflammation, bacterial growth, inadequate tear production). In this review, clinical evidence regarding available treatments and emerging therapies from randomized studies in patients with DED associated with MGD is summarized. Although some treatment modalities have been evaluated specifically for DED patients with MGD, large-scale randomized controlled trials are needed to confirm efficacy and safety in this patient population. Currently, there are no approved prescription pharmacologic treatments specifically indicated for DED associated with MGD, and those medications approved for the treatment of DED do not target the key driver of the disease (i.e., excessive evaporation). NOV03 (perfluorohexyloctane; under review with the US Food and Drug Administration) is the most advanced emerging therapy for DED associated with MGD and has demonstrated statistically significant improvements in both signs and symptoms in randomized controlled trials. Development of novel pharmacotherapies will improve therapeutic options and allow for a more individualized approach for patients with DED associated with MGD.
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Affiliation(s)
- John D Sheppard
- Virginia Eye Consultants and Eastern Virginia Medical School, Suite #210, 241 Corporate Blvd, Norfolk, VA, 23502, USA. .,Eyecare Partners, St. Louis, MO, USA.
| | - Kelly K Nichols
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
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4
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Galor A, Sanchez V, Jensen A, Burton M, Maus K, Stephenson D, Chalfant C, Mandal N. Meibum sphingolipid composition is altered in individuals with meibomian gland dysfunction-a side by side comparison of Meibum and Tear Sphingolipids. Ocul Surf 2022; 23:87-95. [PMID: 34861426 PMCID: PMC8792295 DOI: 10.1016/j.jtos.2021.11.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 01/21/2023]
Abstract
PURPOSE Sphingolipids (SPL) play a role in cell signaling, inflammation, and apoptosis. The purpose of this study was to examine meibum and tear SPL composition in individuals with poor versus good meibum quality. METHODS Individuals were grouped by meibum quality (n = 25 with poor quality, case group and n = 25 with good quality, control group). Meibum and tears were analyzed with liquid chromatography-mass spectrometry (LC-MS) to quantify SPL classes. Semiquantitative and relative composition (mole percent) of SPL and major classes, Ceramide (Cer), Hexosyl-Ceramide (Hex-Cer), Sphingomyelin (SM), Sphingosine (Sph), and sphingosine 1-phosphate (S1P) were compared between groups. RESULTS Demographic characteristics were similar between the two groups. Overall, individuals with poor meibum quality had more SPL pmole in meibum and tears than controls. Relative composition analysis revealed that individuals with poor meibum quality had SPL composed of less Cer, Hex-Cer, and Sph and more SM compared to individuals with good quality meibum. This pattern was not reproduced in tears as individuals with poor meibum quality had SPL composed of a similar amount of Cer, but more Hex-Cer, Sph and SM compared to controls. In meibum, SPL pmole and relative composition most strongly correlated with MG metrics while in tears, SPL pmole and relative composition most strongly correlated with tear production. SPL in both compartments, specifically Cer pmole in meibum and S1P% in tears, correlated with DE symptoms. CONCLUSION SPL composition differs in meibum and tears in patients with poor vs good meibum quality. These findings may be translated into therapeutic targets for disease.
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Affiliation(s)
- Anat Galor
- Miami Veterans Administration Medical Center, 1201 NW 16th St, Miami, FL 33125,Bascom Palmer Eye Institute, University of Miami, 900 NW 17th Street, Miami, FL 33136
| | - Victor Sanchez
- New York University Grossman School of Medicine, New York, NY 10016
| | - Andrew Jensen
- Miami Veterans Administration Medical Center, 1201 NW 16th St, Miami, FL 33125
| | - Madeline Burton
- Department of Ophthalmology, University of Tennessee Health Sciences Center, Hamilton Eye Institute, 930 Madison Avenue, Memphis, TN 38163
| | - Kenneth Maus
- Departments of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL 33620
| | | | - Charles Chalfant
- Departments of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL 33620,The Moffitt Cancer Center, Tampa, FL 33620,Research Service, James A. Haley Veterans Hospital, Tampa, FL 33612
| | - Nawajes Mandal
- Department of Ophthalmology, University of Tennessee Health Sciences Center, Hamilton Eye Institute, 930 Madison Avenue, Memphis, TN 38163,Departments of Anatomy and Neurobiology, and Pharmaceutical Sciences, University of Tennessee Health Sciences Center, 930 Madison Avenue, Memphis, TN 38163,Memphis VA Medical Center, 1030 Jefferson Avenue, Memphis, TN 38104.,Corresponding Author: Nawajes Mandal, PhD, 930 Madison Avenue, Suite 718, Memphis, TN 38163;
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5
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Alotaibi S, Markoulli M, Ozkan J, Papas E. Bio-chemical markers of chronic, non-infectious disease in the human tear film. Clin Exp Optom 2021; 105:166-176. [PMID: 34592130 DOI: 10.1080/08164622.2021.1974282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The tear film is a thin, moist layer covering the ocular surface and is laden with proteins, peptides, lipids, mucins, electrolytes and cellular debris which function to maintain the healthy status of the ocular surface. In many cases of ocular or systemic disease, the integrity of this layer is changed and/or the balance of its constituents is disturbed. Since tears are easy and quick to collect and can be stored for long periods, they have the potential to be a valuable source of information relevant to many disease states. The purpose of this review is to collate information on the known biomarkers of systemic disease that have been identified in tears. The range of conditions covered includes diabetes mellitus, diabetic retinopathy, diabetic peripheral neuropathy, multiple sclerosis, Parkinson's disease, Alzheimer's disease, migraine, systemic sclerosis, cystic fibrosis, thyroid disorders and cancer.
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Affiliation(s)
- Sultan Alotaibi
- Department of Optometry & Vision Science, University of New South Wales, Sydney, Australia.,King Saud University, Riyadh, Saudi Arabia
| | - Maria Markoulli
- Department of Optometry & Vision Science, University of New South Wales, Sydney, Australia
| | - Jerome Ozkan
- Department of Optometry & Vision Science, University of New South Wales, Sydney, Australia
| | - Eric Papas
- Department of Optometry & Vision Science, University of New South Wales, Sydney, Australia
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6
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Lee H, Kim M, Park SY, Kim EK, Seo KY, Kim T. Mechanical meibomian gland squeezing combined with eyelid scrubs and warm compresses for the treatment of meibomian gland dysfunction. Clin Exp Optom 2021; 100:598-602. [DOI: 10.1111/cxo.12532] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/13/2016] [Accepted: 01/05/2017] [Indexed: 12/18/2022] Open
Affiliation(s)
- Hun Lee
- Department of Ophthalmology, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon, South Korea,
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea,
| | - Minseo Kim
- Hankuk Academy of Foreign Studies, Yongin, South Korea,
| | - Si Yoon Park
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea,
| | - Eung Kweon Kim
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea,
- Corneal Dystrophy Research Institute, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea,
| | - Kyoung Yul Seo
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea,
| | - Tae‐im Kim
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea,
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Viitaja T, Raitanen JE, Moilanen J, Paananen RO, Ekholm FS. The Properties and Role of O-Acyl-ω-hydroxy Fatty Acids and Type I-St and Type II Diesters in the Tear Film Lipid Layer Revealed by a Combined Chemistry and Biophysics Approach. J Org Chem 2021; 86:4965-4976. [PMID: 33729799 PMCID: PMC8041317 DOI: 10.1021/acs.joc.0c02882] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
The tear film lipid
layer (TFLL) that covers the ocular surface
contains several unique lipid classes, including O-acyl-ω-hydroxy fatty acids, type I-St diesters, and type II
diesters. While the TFLL represents a unique biological barrier that
plays a central role in stabilizing the entire tear film, little is
known about the properties and roles of individual lipid species.
This is because their isolation from tear samples in sufficient quantities
is a tedious task. To provide access to these species in their pure
form, and to shed light on their properties, we here report a general
strategy for the synthesis and structural characterization of these
lipid classes. In addition, we study the organization and behavior
of the lipids at the air–tear interface. Through these studies,
new insights on the relationship between structural features, such
as number of double bonds and the chain length, and film properties,
such as spreading and evaporation resistance, were uncovered.
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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
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Abstract
The precorneal tear film keeps the eye surface moist and helps to maintain normal eye function. The outermost lipid layer of the tear film, which attenuates tear film evaporation, contains meibum secreted from the meibomian gland. Most meibum lipids are neutral, including wax esters (WEs), cholesteryl esters (CEs), and diesters (DEs), along with some polar lipids including free fatty acids (FFAs), O-acyl-ω-hydroxy fatty acids (OAHFAs), and trace phospholipids. Detection of neutral lipids by mass spectrometry (MS) is challenging due to interference from impurities, particularly when working with minute-volume meibum samples. Here, we describe procedures for sample preparation and MS analysis of these elusive meibum lipids that can be used to examine dry eye disease mechanisms. Because the method described here minimizes impurity peaks for lipids generally, neutral and otherwise, it may be applied to high-sensitivity analysis of other biological samples.
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Affiliation(s)
- Jianzhong Chen
- Department of Optometry and Vision Science, The University of Alabama at Birmingham, Birmingham, AL, USA.
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9
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Bilkhu P, Vidal-Rohr M, Trave-Huarte S, Wolffsohn JS. Effect of meibomian gland morphology on functionality with applied treatment. Cont Lens Anterior Eye 2021; 45:101402. [PMID: 33397598 DOI: 10.1016/j.clae.2020.12.065] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/23/2020] [Accepted: 12/27/2020] [Indexed: 01/19/2023]
Abstract
PURPOSE To determine how Meibomian gland (MG) morphology affects MG function by means of gland expression with the effect of treatment. METHODS Fifteen patients (aged 31.6 ± 13.1 years) from a dry eye clinic diagnosed with MG dysfunction had their 365 lower lid MGs visualised with a slit-lamp biomicroscopy. Using infrared meibography (Oculus K5m), MG length, width and tortuosity were objectively measured. Each MG was expressed and the meibum graded (0=clear fluid, 1=cloudy fluid, 2= particulate fluid, 3=inspissated, or 4 = no expression) to determine its functionality. Participants had functionality repeated each time following a sequence of a warm compress, debridement, and forcible expression after 5 min. RESULTS Just over 10 % of complete length MGs gave clear expression, while about 5% did not express at all, with most expressed meibum being particulate in nature. In contrast, the majority of partial length glands gave inspissated expression (38 %), with 32 % not expressing at all. No MG of <10 % length expressed. MG gland length was correlated with gland expression (r=-0.507, p < 0.001) and MG tortuosity (r=-0.129, p < 0.001), but not MG width (r=-0.090, p = 0.167). Regardless of MG length, warm compress increased the quality of expression (p < 0.002). Debridement further improved expression in partial MGs (p = 0.003), but not forcible expression (p = 0.529). CONCLUSIONS Length is the key functional morphology metric of lower lid MGs. Warm compress and massage increase the quality of expression in all, but the shortest glands and patients with partial length glands also benefit from debridement.
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Affiliation(s)
- Paramdeep Bilkhu
- Ophthalmic Research Group, School of Life & Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom
| | - Maria Vidal-Rohr
- Ophthalmic Research Group, School of Life & Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom
| | - Sonia Trave-Huarte
- Ophthalmic Research Group, School of Life & Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom
| | - James S Wolffsohn
- Ophthalmic Research Group, School of Life & Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom.
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10
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Untargeted lipidomic analysis of human tears: A new approach for quantification of O-acyl-omega hydroxy fatty acids. Ocul Surf 2019; 17:347-355. [PMID: 30818035 DOI: 10.1016/j.jtos.2019.02.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 02/10/2019] [Accepted: 02/13/2019] [Indexed: 02/06/2023]
Abstract
PURPOSE The purpose of this work was to optimize methodology to analyze the human tear film lipids by using untargeted, direct infusion electrospray ionization-mass spectrometry (ESI-MS) to establish the analytical approach for a large-scale clinical translational study of tear film lipids in ocular surface disease, particularly associated with the O-acyl-omega hydroxy fatty acids (OAHFAs). METHODS Meibum and tear samples were collected from both eyes of five normal subjects without ocular disease using two different microcapillary collection tubes, glass and polytetrafluoroethylene (PTFE). An untargeted lipidomics approach was used to analyze the lipids in human tear and meibum samples using direct infusion ESI-MS in positive and negative ion modes. Direct and indirect quantification methods were evaluated. RESULTS The amount of OAHFAs measured in tears using these techniques was approximately 0.7-0.8% of the total lipids. More phospholipids, including phosphatidylcholine and sphingomyelin, were detected in the tear samples associated with glass microcapillaries compared to PTFE. CONCLUSIONS Reliable assessment of lipids in small volumes of tear film is possible using high resolution, untargeted ESI-MS in positive and negative ion modes. Using this technique, the concentration of OAHFAs can be quantified, as can the presence of other polar lipids.
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11
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Chen J, Panthi S. Lipidomic analysis of meibomian gland secretions from the tree shrew: Identification of candidate tear lipids critical for reducing evaporation. Chem Phys Lipids 2019; 220:36-48. [PMID: 30660743 DOI: 10.1016/j.chemphyslip.2019.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/08/2019] [Accepted: 01/14/2019] [Indexed: 02/07/2023]
Abstract
Lipids secreted from the meibomian glands form the outermost layer of the tear film and reduce its evaporation. Abnormal changes in the quantities or compositions of lipids present in meibomian gland secretions (meibum) are known to lead to dry eye disease, although the underlying mechanism is not yet well understood. The tree shrew is the non-primate mammal most closely related to humans. To assess the utility of the tree shrew as a model for the study of dry eye disease, we analyzed the lipid profile of tree shrew meibum using an untargeted ESI-MS and MS/MSall shotgun approach. The resulting lipidome shared many similarities with human meibum, while displaying some interesting differences. For example, several classes of lipids, including wax esters, cholesteryl esters, diesters, and (O-acyl)-ω-hydroxy fatty acids, had relatively longer chain lengths in tree shrew meibum. These increases in length may promote more effective reduction of tear evaporation in the tree shrew, which likely underlies the much longer blinking interval of this mammal. Our results suggest that the tree shrew could be an effective model for the study of dry eye.
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Affiliation(s)
- Jianzhong Chen
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
| | - Shyam Panthi
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
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12
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Abstract
The members of the Tear Film Subcommittee reviewed the role of the tear film in dry eye disease (DED). The Subcommittee reviewed biophysical and biochemical aspects of tears and how these change in DED. Clinically, DED is characterized by loss of tear volume, more rapid breakup of the tear film and increased evaporation of tears from the ocular surface. The tear film is composed of many substances including lipids, proteins, mucins and electrolytes. All of these contribute to the integrity of the tear film but exactly how they interact is still an area of active research. Tear film osmolarity increases in DED. Changes to other components such as proteins and mucins can be used as biomarkers for DED. The Subcommittee recommended areas for future research to advance our understanding of the tear film and how this changes with DED. The final report was written after review by all Subcommittee members and the entire TFOS DEWS II membership.
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Chen J, Keirsey JK, Green KB, Nichols KK. Expression Profiling of Nonpolar Lipids in Meibum From Patients With Dry Eye: A Pilot Study. Invest Ophthalmol Vis Sci 2017; 58:2266-2274. [PMID: 28426869 PMCID: PMC5398788 DOI: 10.1167/iovs.16-20902] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Purpose The purpose of this investigation was to characterize differentially expressed lipids in meibum samples from patients with dry eye disease (DED) in order to better understand the underlying pathologic mechanisms. Methods Meibum samples were collected from postmenopausal women with DED (PW-DED; n = 5) and a control group of postmenopausal women without DED (n = 4). Lipid profiles were analyzed by direct infusion full-scan electrospray ionization mass spectrometry (ESI-MS). An initial analysis of 145 representative peaks from four classes of lipids in PW-DED samples revealed that additional manual corrections for peak overlap and isotopes only slightly affected the statistical analysis. Therefore, analysis of uncorrected data, which can be applied to a greater number of peaks, was used to compare more than 500 lipid peaks common to PW-DED and control samples. Statistical analysis of peak intensities identified several lipid species that differed significantly between the two groups. Data from contact lens wearers with DED (CL-DED; n = 5) were also analyzed. Results Many species of the two types of diesters (DE) and very long chain wax esters (WE) were decreased by ∼20% in PW-DED, whereas levels of triacylglycerols were increased by an average of 39% ± 3% in meibum from PW-DED compared to that in the control group. Approximately the same reduction (20%) of similar DE and WE was observed for CL-DED. Conclusions Statistical analysis of peak intensities from direct infusion ESI-MS results identified differentially expressed lipids in meibum from dry eye patients. Further studies are warranted to support these findings.
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Affiliation(s)
- Jianzhong Chen
- School of Optometry, University of Alabama-Birmingham, Birmingham, Alabama, United States
| | - Jeremy K Keirsey
- Mass Spectrometry and Proteomics Facility, The Ohio State University, Columbus, Ohio, United States
| | - Kari B Green
- Department of Chemistry, University of Florida, Gainesville, Florida, United States
| | - Kelly K Nichols
- School of Optometry, University of Alabama-Birmingham, Birmingham, Alabama, United States
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Meibomian glands, meibum, and meibogenesis. Exp Eye Res 2017; 163:2-16. [PMID: 28669846 DOI: 10.1016/j.exer.2017.06.020] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/14/2017] [Accepted: 06/28/2017] [Indexed: 12/28/2022]
Abstract
Meibum is a lipid-rich secretion that is produced by fully differentiated meibocytes in the holocrine Meibomian glands (MG) of humans and most mammals. The secretion is a part of a defense mechanism that protects the ocular surface from hazardous environmental factors, and from desiccation. Meibomian lipids that have been identified in meibum are very diverse and unique in nature. The lipid composition of meibum is different from virtually any other lipid pool found in the human body. In fact, meibum is quite different from sebum, which is the closest secretion that is produced by anatomically, physiologically, and biochemically related sebaceous glands. However, meibum of mice have been shown to closely resemble that of humans, implying similar biosynthetic mechanisms in MG of both species. By analyzing available genomic, immunohistochemical, and lipidomic data, we have envisioned a unifying network of enzymatic reactions that are responsible for biosynthesis of meibum, which we call meibogenesis. Our current theory is based on an assumption that most of the biosynthetic reactions of meibogenesis are catalyzed by known enzymes. However, the main features that make meibum unique - the ratio of identified classes of lipids, the extreme length of its components, extensive ω-hydroxylation of fatty acids and alcohols, iso- and anteiso-branching of meibomian lipids (e.g. waxes), and the presence of rather unique complex lipids with several ester bonds - make it possible that either the activity of known enzymes is altered in MG, or some unknown enzymes contribute to the processes of meibogenesis, or both. Studies are in progress to elucidate meibogenesis on molecular level.
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