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Liu R, Tu M, Xue J, Xiao B, Li J, Liang L. Oleic acid induces lipogenesis and NLRP3 inflammasome activation in organotypic mouse meibomian gland and human meibomian gland epithelial cells. Exp Eye Res 2024; 241:109851. [PMID: 38453039 DOI: 10.1016/j.exer.2024.109851] [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] [Received: 08/08/2023] [Revised: 02/29/2024] [Accepted: 03/03/2024] [Indexed: 03/09/2024]
Abstract
The accumulation of oleic acid (OA) in the meibum from patients with meibomian gland dysfunction (MGD) suggests that it may contribute to meibomian gland (MG) functional disorder, as it is a potent stimulator of acne-related lipogenesis and inflammation in sebaceous gland. Therefore, we investigate whether OA induces lipogenesis and inflammasome activation in organotypic cultured mouse MG and human meibomian gland epithelial cells (HMGECs). Organotypic cultured mouse MG and HMGECs were exposed to OA or combinations with specific AMPK agonists 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR). Lipogenic status, ductal keratinization, squamous metaplasia, NLRP3/ASC/Caspase-1 inflammasome activation, proinflammatory cytokine IL-1β production, and AMPK pathway phosphorylation in MG were subsequently examined by lipid staining, immunofluorescence staining, immunohistochemical staining, ELISA assay, and Western blot analyses. We found that OA significantly induced lipid accumulation, ductal keratinization, and squamous metaplasia in organotypic cultured MG, as evidenced by increased lipids deposition within acini and duct, upregulated expression of lipogenic proteins (SREBP-1 and HMGCR), and elevation of K10/Sprr1b. Additionally, OA induced NLRP3/ASC/Caspase-1 inflammasome activation, cleavage of Caspase-1, and production of downstream proinflammatory cytokine IL-1β. The findings of lipogenesis and NLRP3-related proinflammatory response in OA-stimulated HMGECs were consistent with those in organotypic cultured MG. OA exposure downregulated phospho-AMPK in two models, while AICAR treatment alleviated lipogenesis by improving AMPK/ACC phosphorylation and SREBP-1/HMGCR expression. Furthermore, AMPK amelioration inhibited activation of the NLRP3/ASC/Caspase-1 axis and secretion of IL-1β, thereby relieving the OA-induced proinflammatory response. These results demonstrated that OA induced lipogenic disorder and NLRP3 inflammasome activation in organotypic cultured mouse MG and HMGECs by suppressing the AMPK signaling pathway, indicating OA may play an etiological role in MGD.
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Affiliation(s)
- Ren Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Mengqian Tu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Jianwen Xue
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Bing Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Jing Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China.
| | - Lingyi Liang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China.
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Wang Z, Yang T, Brenna JT, Wang DH. Fatty acid isomerism: analysis and selected biological functions. Food Funct 2024; 15:1071-1088. [PMID: 38197562 DOI: 10.1039/d3fo03716a] [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: 01/11/2024]
Abstract
The biological functions of fatty acids and the lipids in which they are esterified are determined by their chain length, double bond position and geometry and other structural motifs such as the presence of methyl branches. Unusual isomeric features in fatty acids of human foods such as conjugated double bonds or chain branching found in dairy products, some seeds and nuts, and marine foods potentially have important effects on human health. Recent advancements in identifying fatty acids with unusual double bond positions and pinpointing the position of methyl branches have empowered the study of their biological functions. We present recent advances in fatty acid structural elucidation by mass spectrometry in comparison with the more traditional methods. The double bond position can be determined by purely instrumental methods, specifically solvent-mediated covalent adduct chemical ionization (SM-CACI) and ozone induced dissociation (OzID), with charge inversion methods showing promise. Prior derivatization using the Paternò-Büchi (PB) reaction to yield stable structures that, upon collisional activation, yield the double bond position has emerged. The chemical ionization (CI) based three ion monitoring (MRM) method has been developed to simultaneously identify and quantify low-level branched chain fatty acids (BCFAs), unattainable by electron ionization (EI) based methods. Accurate identification and quantification of unusual fatty acid isomers has led to research progress in the discovery of biomarkers for cancer, diabetes, nonalcoholic fatty liver disease (NAFLD) and atherosclerosis. Modulation of eicosanoids, weight loss and the health significance of BCFAs are also presented. This review clearly shows that the improvement of analytical capacity is critical in the study of fatty acid biological functions, and stronger coupling of the methods discussed here with fatty acid mechanistic research is promising in generating more refined outcomes.
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Affiliation(s)
- Zhen Wang
- School of Agriculture, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China.
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China
| | - Tingxiang Yang
- School of Agriculture, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China.
| | - J Thomas Brenna
- Dell Pediatric Research Institute, Depts of Pediatrics, of Chemistry, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, TX, USA.
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Dong Hao Wang
- School of Agriculture, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China.
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Lu H, Wang Z, Cao B, Cong F, Wang X, Wei W. Dietary sources of branched-chain fatty acids and their biosynthesis, distribution, and nutritional properties. Food Chem 2024; 431:137158. [PMID: 37604010 DOI: 10.1016/j.foodchem.2023.137158] [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: 04/07/2023] [Revised: 08/05/2023] [Accepted: 08/13/2023] [Indexed: 08/23/2023]
Abstract
Branched-chain fatty acids (BCFAs) consist of a wide variety of fatty acids with alkyl branching of methyl group. The most common BCFAs are the types with one methyl group (mmBCFA) on the penultimate carbon (iBCFA) or the antepenultimate carbon (aiBCFA). Long-chain mmBCFAs are widely existing in animal fats, milks and are mostly derived from bacteria in the diet or animal digestive system. Recent studies show that BCFAs benefit human intestinal health and immune homeostasis, but the connection between their content, distribution in the human and their nutritional functions are not well established. In this paper, we reviewed BCFAs from various dietary sources focused on their molecular species. The BCFAs biosynthesis in bacteria, Caenorhabditis elegans, mammals and their distribution in human tissues are summarized. This paper also discusses the nutritional properties of BCFAs including influences on intestinal health, immunoregulatory effects, anti-carcinoma, and anti-obesity activities, by highlighting the most recent research progress.
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Affiliation(s)
- Huijia Lu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Zhen Wang
- Wilmar (Shanghai) Biotechnology Research & Development Center, Shanghai 200137, China; School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen 518107, China
| | - Bo Cao
- Wilmar (Shanghai) Biotechnology Research & Development Center, Shanghai 200137, China
| | - Fang Cong
- Wilmar (Shanghai) Biotechnology Research & Development Center, Shanghai 200137, China.
| | - Xingguo Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Wei Wei
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
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Dogan L, Arslan GD. Evaluation of the Tear Meniscus Using Optical Coherence Tomography in Meibomian Gland Dysfunction. Ocul Immunol Inflamm 2023; 31:1785-1791. [PMID: 36043889 DOI: 10.1080/09273948.2022.2113802] [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] [Received: 02/15/2022] [Accepted: 08/11/2022] [Indexed: 10/14/2022]
Abstract
INTRODUCTION This study aimed to evaluate tear meniscus parameters in meibomian gland dysfunction (MGD) using optical coherence tomography and ImageJ software. METHODS We enrolled 66 eyes of 66 participants and measured tear meniscus parameters, including height, depth, turbidity, and percentage area occupied by particles (PAOP) in the meniscus in the MGD and control groups. RESULTS Tear meniscus turbidity and PAOP were significantly higher in the MGD group, but tear meniscus height (TMH) and depth (TMD) did not differ significantly between groups. Tear meniscus turbidity and PAOP were positively correlated with each other and ocular surface parameters, including OSDI and ocular surface staining scores. CONCLUSION Tear meniscus turbidity and PAOP were higher in the MGD group than in the control group; therefore, they can be used as significant non-invasive parameters in the prediction of MGD. TMH and TMD did not differ significantly between groups.
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Affiliation(s)
- Levent Dogan
- Department of Ophthalmology, Tatvan State Hospital, Bitlis, Turkey
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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
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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.
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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
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Blanco-Campoy DG, Graue-Hernández EO, Quiróz-Casian N, Vélez-Cordero JR, Yáñez-Soto B. In-vitro evaluation of the evaporation retardation by Meibomian lipids in homogeneous and non-homogeneous evaporation. J Colloid Interface Sci 2022; 625:210-219. [PMID: 35716616 DOI: 10.1016/j.jcis.2022.06.032] [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: 07/29/2021] [Revised: 05/25/2022] [Accepted: 06/06/2022] [Indexed: 10/31/2022]
Abstract
HYPOTHESIS An important function of the Tear Film Lipid Layer (TFLL) is the retardation of evaporation. We propose two micro-scaled systems to quantify the influence of the TFLL in evaporation for single patients, which may contribute as an improvement on the diagnosis of Meibomian Gland Dysfunctions (MGD). EXPERIMENTS Meibum was extracted from 10 patients with hypersecretory MGD and 9 healthy controls. The lipids were placed over water, and the evaporation was determined in the case of homogeneous evaporation over a surface (pendant drop), and the case where the evaporation depends on a pinned triple contact line (meniscus). FINDINGS For the homogeneous case, the presence of Meibum reduced evaporation in 30%, although there was no significant difference between controls and MGD patients. However, evaporation induced by menisci was 25 % higher in MGD patients. Our results contribute to the evidence of the inhibition of evaporation by Meibum. Our study also suggests that the evaporation induced by contact points may be a more relevant model to measure differences in evaporation due to the composition of Meibum. This model may also have connotations in the occurrence of internal stresses in the tear film, inducing its instability.
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Affiliation(s)
| | - Enrique O Graue-Hernández
- Cornea & Refractive Surgery, Instituto de Oftalmología Fundación Conde de Valenciana, IAP, 06700, México
| | - Natalia Quiróz-Casian
- Cornea & Refractive Surgery, Instituto de Oftalmología Fundación Conde de Valenciana, IAP, 06700, México
| | - Juan R Vélez-Cordero
- Conacyt - Instituto de Física, Universidad Autónoma de San Luis Potosí 78000, México.
| | - Bernardo Yáñez-Soto
- Conacyt - Instituto de Física, Universidad Autónoma de San Luis Potosí 78000, México.
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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.
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Jian R, Zhao X, Lin Q, Xia Y. Profiling of branched-chain fatty acids via nitroxide radical-directed dissociation integrated on an LC-MS/MS workflow. Analyst 2022; 147:2115-2123. [DOI: 10.1039/d2an00266c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
By coupling O-benzylhydroxylamine derivatization and tandem mass spectrometry, nitroxide radical-induced dissociation can be initiated via collisional activation which enables the analysis of methyl branching(s) in fatty acids.
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Affiliation(s)
- Ruijun Jian
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biological, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Xue Zhao
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biological, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Qiaohong Lin
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biological, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yu Xia
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biological, Department of Chemistry, Tsinghua University, Beijing 100084, China
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Gao H, Chen H, Xie HT, Xu KK, Shi BJ, Huang YK. Changes in Meibum Lipid Composition With Ocular Demodex Infestation. Transl Vis Sci Technol 2021; 10:6. [PMID: 34874449 PMCID: PMC8662575 DOI: 10.1167/tvst.10.14.6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Purpose The purpose of this study was to understand the impact of Demodex infection in the lipid component of meibum in patients. Methods The meibum samples were collected from four groups of subjects: (1) Demodex-negative with non-MGD (D−M−; n = 10); (2) Demodex-positive with non-MGD (D+M−; n = 10); (3) Demodex-negative with MGD (D−M+; n = 10); and (4) Demodex-positive with MGD (D+M+; n = 10). A liquid chromatography–mass spectrometry (LC-MS) system consisting of ultra-performance liquid chromatography and a Q Exactive high-resolution mass spectrometer was used for lipids separation and detection. Results Compared with the D−M− group, the D+M− group had lower levels of phosphatidylcholines (PCs) and lysophosphatidylcholines (LPCs) and higher levels of phosphatidylethanolamines (PEs). Compared with the D−M+ group, the levels of sphingomyelins (SMs) and PCs in the D+M+ group were decreased, whereas the levels of (O-acyl)-ω-hydroxy fatty acids (OAHFAs), ceramides (CERs), LPCs, and diacylglycerols (DGs) were significantly increased. Triacylglycerols (TGs), DGs, CERs, and OAHFAs were decreased in D−M+ group, whereas levels of PEs, phosphatidylinositols, and phosphatidylglycerols were increased in meibum obtained from the D−M+ group compared with those in the D−M− group. TGs, SMs, CERs, and PEs were decreased in the D+M+ group, whereas levels of LPCs, LPEs, PCs, and PEs were increased in meibum from the D−M+ group compared with those in the D+M− group. Conclusions To the best of our knowledge, this is the first study to assess the changes in meibum from patients with ocular Demodex infestation. The significant increase of OAHFAs in the Demodex-positive group suggest that OAHFAs may be associated with the progress of ocular Demodex infections. Translational Relevance OAHFAs could be a potential new therapeutic target for ocular Demodex infestation.
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Affiliation(s)
- Hui Gao
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Aier Eye Hospital of Wuhan University, Wuhan, China
| | - Hua Chen
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hua-Tao Xie
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kang-Kang Xu
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bing-Jie Shi
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yu-Kan Huang
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Phan MAT, Madigan MC, Stapleton F, Willcox M, Golebiowski B. Human meibomian gland epithelial cell culture models: Current progress, challenges, and future directions. Ocul Surf 2021; 23:96-113. [PMID: 34843998 DOI: 10.1016/j.jtos.2021.11.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/04/2021] [Accepted: 11/23/2021] [Indexed: 12/13/2022]
Abstract
The widely used immortalised human meibomian gland epithelia cell (iHMGEC) line has made possible extensive studies of the biology and pathophysiology of meibomian glands (MG). Tissue culture protocols for iHMGEC have been revised and modified to optimise the growth conditions for cell differentiation and lipid accumulation. iHMGEC proliferate in serum-free medium but require serum or other appropriate exogenous factors to differentiate. Several supplements can enhance differentiation and neutral lipid accumulation in iHMGEC grown in serum-containing medium. In serum-free medium, rosiglitazone, a peroxisome proliferator activator receptor-γ (PPARγ) agonist, is reported to induce iHMGEC differentiation, neutral lipid accumulation and expression of key biomarkers of differentiation. iHMGEC cultured in serum-containing medium under hypoxia or with azithromycin increases DNAse 2 activity, a biomarker of terminal differentiation in sebocytes. The production of lipids with composition similar to meibum has not been observed in vitro and this remains a major challenge for iHMGEC culture. Innovative methodologies such as 3D ex vivo culture of MG and generation of MG organoids from stem cells are important for further developing a model that more closely mimics the in vivo biology of human MG and to facilitate the next generation of studies of MG disease and dry eye.
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Affiliation(s)
- Minh Anh Thu Phan
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW Sydney, NSW, 2033, Australia.
| | - Michele C Madigan
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW Sydney, NSW, 2033, Australia
| | - Fiona Stapleton
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW Sydney, NSW, 2033, Australia
| | - Mark Willcox
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW Sydney, NSW, 2033, Australia
| | - Blanka Golebiowski
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW Sydney, NSW, 2033, Australia
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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: 5] [Impact Index Per Article: 1.7] [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.
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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
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Butovich IA, Wilkerson A, Yuksel S. Differential effects of dietary cholesterol and triglycerides on the lipid homeostasis in Meibomian glands. J Steroid Biochem Mol Biol 2021; 211:105894. [PMID: 33819631 PMCID: PMC8217181 DOI: 10.1016/j.jsbmb.2021.105894] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 03/21/2021] [Accepted: 03/31/2021] [Indexed: 12/20/2022]
Abstract
Exocrine Meibomian glands (MG) play a central role in the ocular surface physiology by producing meibum - a lipid secretion composed of cholesteryl esters (CE), cholesterol (Chl), triacylgycerols (TAG), waxes and other types of lipids. MG were previously shown to synthesize Meibomian lipids (ML) in situ via a complex array of reactions termed meibogenesis. However, questions remain about the role of dietary lipids in meibogenesis. To establish if dietary Chl (DC) and TAG (DT) can participate in meibogenesis, we studied mice whose diet was supplemented with trace amounts of deuterated Chl (2H-Chl) and 13C-labeled triolein (13C-TO), and the products of their biosynthetic transformations were analyzed using LC/MS. We demonstrated that 2H-Chl, but not 13C-TO, could be directly incorporated into meibum. Furthermore, 2H-Chl was esterified into MG-specific ultra long 2H-CE, which were vastly different from plasma CE and 2H-CE. The measured 2H-Chl/Chl and 2H-CE/CE ratios in meibum increased in a time-dependent manner reaching ∼5% and ∼1.2 %, respectively. The 2H-Chl/2H-CE ratio was about 3.5x higher than that for endogenous unlabeled Chl and CE, indicating accumulation of 2H-Chl in meibum. The elongation pattern of Meibomian 2H-CE closely replicated that of unlabeled CE. On the other hand, 13C-TO was not detected in any of the ML samples as an intact lipid or its metabolized/hydrolyzed products. We conclude that DC can be directly esterified into MG-specific CE, while DT undergo extensive catabolic transformations before reaching MG. These findings demonstrate that DC can have a direct impact on MG and ocular surface lipid homeostasis and pathophysiology.
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Affiliation(s)
- Igor A Butovich
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-9057, USA; The Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, 75390-9057, USA.
| | - Amber Wilkerson
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-9057, USA
| | - Seher Yuksel
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-9057, USA
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Wang LX, Deng YP. Androgen and meibomian gland dysfunction: from basic molecular biology to clinical applications. Int J Ophthalmol 2021; 14:915-922. [PMID: 34150548 DOI: 10.18240/ijo.2021.06.18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/20/2020] [Indexed: 02/08/2023] Open
Abstract
Meibomian gland, the largest sebaceous gland of the body, is responsible for the biosynthesis of lipid layer of the tear film to prevent excessive evaporation. The loss of normal functions of meibomian gland, known as meibomian gland dysfunction (MGD), is a chronic disease and is the leading cause of dry eye symptoms in the clinics. Studies have found sex hormones, especially androgen, play vital roles in the regulation of the functions of meibomian gland. Recently, androgen has also been preliminarily applied in clinics for the treatment of MGD and showed promising results, especially in people with endogenous androgen deficiency. This review summarized the mechanisms of the function of androgen on meibomian gland based on molecular, animal, and clinical studies, and proposed evidence-based views about its potential applications for the treatment of MGD.
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Affiliation(s)
- Li-Xiang Wang
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Ying-Ping Deng
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan Province, China
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15
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Borchman D. Lipid conformational order and the etiology of cataract and dry eye. J Lipid Res 2021; 62:100039. [PMID: 32554545 PMCID: PMC7910524 DOI: 10.1194/jlr.tr120000874] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/15/2020] [Indexed: 12/12/2022] Open
Abstract
Lens and tear film lipids are as unique as the systems they reside in. The major lipid of the human lens is dihydrosphingomylein, found in quantity only in the lens. The lens contains a cholesterol to phospholipid molar ratio as high as 10:1, more than anywhere else in the body. Lens lipids contribute to maintaining lens clarity, and alterations in lens lipid composition due to age are likely to contribute to cataract. Lens lipid composition reflects adaptations to the unique characteristics of the lens: no turnover of lens lipids or proteins; the lowest amount of oxygen of any tissue; and contains almost no intracellular organelles. The tear film lipid layer (TFLL) is also unique. The TFLL is a thin (100 nm) layer of lipid on the surface of tears covering the cornea that contributes to tear film stability. The major lipids of the TFLL are wax esters and cholesterol esters that are not found in the lens. The hydrocarbon chains associated with the esters are longer than those found anywhere else in the body (as long as 32 carbons), and many are branched. Changes in the composition and structure of the 30,000 different moieties of TFLL contribute to the instability of tears. The focus of the current review is how spectroscopy has been used to elucidate the relationships between lipid composition, conformational order and function, and the etiology of cataract and dry eye.
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Affiliation(s)
- Douglas Borchman
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY 40202.
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Yeboah GK, Lobanova ES, Brush RS, Agbaga MP. Very long chain fatty acid-containing lipids: a decade of novel insights from the study of ELOVL4. J Lipid Res 2021; 62:100030. [PMID: 33556440 PMCID: PMC8042400 DOI: 10.1016/j.jlr.2021.100030] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 01/12/2021] [Accepted: 01/27/2021] [Indexed: 11/18/2022] Open
Abstract
Lipids play essential roles in maintaining cell structure and function by modulating membrane fluidity and cell signaling. The fatty acid elongase-4 (ELOVL4) protein, expressed in retina, brain, Meibomian glands, skin, testes and sperm, is an essential enzyme that mediates tissue-specific biosynthesis of both VLC-PUFA and VLC-saturated fatty acids (VLC-SFA). These fatty acids play critical roles in maintaining retina and brain function, neuroprotection, skin permeability barrier maintenance, and sperm function, among other important cellular processes. Mutations in ELOVL4 that affect biosynthesis of these fatty acids cause several distinct tissue-specific human disorders that include blindness, age-related cerebellar atrophy and ataxia, skin disorders, early-childhood seizures, mental retardation, and mortality, which underscores the essential roles of ELOVL4 products for life. However, the mechanisms by which one tissue makes VLC-PUFA and another makes VLC-SFA, and how these fatty acids exert their important functional roles in each tissue, remain unknown. This review summarizes research over that last decade that has contributed to our current understanding of the role of ELOVL4 and its products in cellular function. In the retina, VLC-PUFA and their bioactive "Elovanoids" are essential for retinal function. In the brain, VLC-SFA are enriched in synaptic vesicles and mediate neuronal signaling by determining the rate of neurotransmitter release essential for normal neuronal function. These findings point to ELOVL4 and its products as being essential for life. Therefore, mutations and/or age-related epigenetic modifications of fatty acid biosynthetic gene activity that affect VLC-SFA and VLC-PUFA biosynthesis contribute to age-related dysfunction of ELOVL4-expressing tissues.
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Affiliation(s)
- Gyening Kofi Yeboah
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Ekaterina S Lobanova
- Department of Ophthalmology Research, University of Florida, Gainesville, FL, USA
| | - Richard S Brush
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Dean A. McGee Eye Institute, Oklahoma City, OK, USA
| | - Martin-Paul Agbaga
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Dean A. McGee Eye Institute, Oklahoma City, OK, USA.
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Relation of Dietary Fatty Acids and Vitamin D to the Prevalence of Meibomian Gland Dysfunction in Japanese Adults: The Hirado-Takushima Study. J Clin Med 2021; 10:jcm10020350. [PMID: 33477594 PMCID: PMC7831319 DOI: 10.3390/jcm10020350] [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: 12/01/2020] [Revised: 12/29/2020] [Accepted: 01/14/2021] [Indexed: 01/04/2023] Open
Abstract
Intervention studies have shown that n-3 polyunsaturated fatty acid (PUFA) supplementation is effective for the treatment of meibomian gland dysfunction (MGD). Ointment containing an analog of vitamin D has also been found to improve symptoms and signs of MGD. We have now evaluated the relation of MGD prevalence to dietary intake of fatty acids (FAs) and vitamin D among a Japanese population. Subjects comprised 300 adults aged 20 to 92 years residing on Takushima Island. MGD was diagnosed on the basis of subjective symptoms, lid margin abnormalities, and meibomian gland obstruction. Dietary FA and vitamin D intake was estimated with a brief-type self-administered diet history questionnaire. MGD prevalence was 35.3%. Multivariate adjusted odds ratios (95% confidence intervals) between extreme quintiles of intake for MGD prevalence were 0.40 (0.16–0.97) for total fat, 0.40 (0.17–0.97) for saturated FAs, 0.40 (0.17–0.97) for oleic acid, 0.52 (0.23–1.18) for n-3 PUFAs, 0.63 (0.27–1.49) for n-6 PUFAs, 1.32 (0.59–2.95) for the n-6/n-3 PUFA ratio, and 0.38 (0.17–0.87) for vitamin D. Total fat, saturated FA, oleic acid, and vitamin D intake may thus be negatively associated with MGD prevalence in the Japanese.
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Butovich IA, Suzuki T. Delineating a novel metabolic high triglycerides-low waxes syndrome that affects lipid homeostasis in meibomian and sebaceous glands. Exp Eye Res 2020; 199:108189. [PMID: 32805264 DOI: 10.1016/j.exer.2020.108189] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/12/2020] [Accepted: 08/07/2020] [Indexed: 10/23/2022]
Abstract
Meibomian glands that are embedded in tarsal plates of human eyelids, and sebaceous glands found in the skin, including that of eyelids, are two related types of holocrine glands that produce lipid-rich secretions called meibum and sebum. Pervasive ocular disorders, such as Meibomian gland dysfunction and dry eye, have been linked to changes in the lipid composition of meibum. However, in most described cases the changes were either small, or random, or insufficiently characterized on the molecular level. Here, we present results of comprehensive lipidomic analyses of meibum, tears and sebum of a patient whose secretions were highly abnormal (abnormal meibum, tears and sebum, or AMTS, patient). The lipidomes were characterized on the level of individual lipid species using ultra-high performance liquid chromatography and high resolution mass spectrometry. The major differences between the AMTS patient and normal age- and gender-matched subjects included, among others, severely diminished pools of normal meibomian lipids such as wax esters and cholesteryl esters in meibum and tears, a 2x increase in total cholesteryl esters to wax esters ratio, their skewed molecular profiles, a ~3x increase in free cholesterol to cholesteryl esters ratio, and, most importantly, a 20x to 30x increase in the triglicerides fraction over the norm. Sebum of the AMTS patient was also highly abnormal lacking major wax esters. Notably, the routine blood lipid panel test of the AMTS patient showed no abnormalities. The data imply that the AMTS patient had a severe, previously unreported, metabolic disorder that affected meibogenesis in Meibomian glands and sebogenesis in sebaceous glands. This is, to the best of our knowledge, a first observation of the condition that we have termed High Triglycerides/Low Waxes (HTLW) syndrome.
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Affiliation(s)
- Igor A Butovich
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Tomo Suzuki
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan; Department of Ophthalmology, Kyoto City Hospital Organization, Kyoto, Japan
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19
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Impact of meibomian gland width on successful contact lens use. Cont Lens Anterior Eye 2019; 42:646-651. [DOI: 10.1016/j.clae.2019.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 05/08/2019] [Accepted: 06/17/2019] [Indexed: 01/13/2023]
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20
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Wang Z, Wang DH, Park HG, Tobias HJ, Kothapalli KSD, Brenna JT. Structural Identification of Monounsaturated Branched Chain Fatty Acid Methyl Esters by Combination of Electron Ionization and Covalent Adduct Chemical Ionization Tandem Mass Spectrometry. Anal Chem 2019; 91:15147-15154. [DOI: 10.1021/acs.analchem.9b03912] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Zhen Wang
- Department of Food Science, Cornell University, Ithaca, New York 14853, United States
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition,, The University of Texas at Austin, 1400 Barbara Jordan Blvd., Austin, Texas 78723, United States
| | - Dong Hao Wang
- Department of Food Science, Cornell University, Ithaca, New York 14853, United States
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition,, The University of Texas at Austin, 1400 Barbara Jordan Blvd., Austin, Texas 78723, United States
| | - Hui Gyu Park
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition,, The University of Texas at Austin, 1400 Barbara Jordan Blvd., Austin, Texas 78723, United States
| | - Herbert J. Tobias
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition,, The University of Texas at Austin, 1400 Barbara Jordan Blvd., Austin, Texas 78723, United States
| | - Kumar S. D. Kothapalli
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition,, The University of Texas at Austin, 1400 Barbara Jordan Blvd., Austin, Texas 78723, United States
| | - J. Thomas Brenna
- Department of Food Science, Cornell University, Ithaca, New York 14853, United States
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition,, The University of Texas at Austin, 1400 Barbara Jordan Blvd., Austin, Texas 78723, United States
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21
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Suzuki T, Fujiwara S, Kinoshita S, Butovich IA. Cyclic Change of Fatty Acid Composition in Meibum During the Menstrual Cycle. Invest Ophthalmol Vis Sci 2019; 60:1724-1733. [PMID: 31013345 PMCID: PMC6736406 DOI: 10.1167/iovs.18-26390] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Purpose To evaluate the fatty acid (FA) composition in the meibum of pre- and postmenopausal women and age-matched men. Methods This prospective study involved 24 healthy subjects; six premenopausal women in their 30s with a regular menstrual cycle (young-female [yF] group), six postmenopausal women in their 60s (elderly-female [eF] group), and 12 age-matched men (i.e., young-male [yM] and elderly-male [eM] groups, respectively). The menstrual cycle was divided into six phases (phase I–VI). Meibum was obtained from the meibomian gland orifices via a Daviel spoon, and its FA composition was then analyzed via gas chromatography mass spectrometry (GC-MS). Principal component analysis (PCA) was performed on the GC-MS results. Results The mean FA composition of all subjects was 40% saturated FAs (SFA) and 60% unsaturated FAs (UFAs). The PCA results of all groups indicated two categories (PC1 [77.5%] and PC2 [12.4%]); one consisting of yF-group samples of mainly phase II and III and the other consisting of the yF-group samples of the rest of the cycle, as well as from eF-group, yM-group, and eM-group samples. Each group had a distinctive nature. The FAs that most contributed to PC1 were C14:0, C16:0, and C18:0 in a positive correlation, and C18:1n9 in a negative correlation. Conclusions FA composition noticeably changes during the menstrual cycle and is somewhat affected by sex and age. The ratio of SFAs (C16:0, C18:0) to mono-UFAs (C18:1n9) in the FA composition might have an impact on the lipid quality of meibum, thus suggesting alteration of its melting temperature and viscosity.
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Affiliation(s)
- Tomo Suzuki
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Department of Ophthalmology, Kyoto City Hospital Organization, Kyoto, Japan
| | | | - Shigeru Kinoshita
- Department of Frontier Medical Science and Technology for Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Igor A Butovich
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
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Butovich IA, Bhat N, Wojtowicz JC. Comparative Transcriptomic and Lipidomic Analyses of Human Male and Female Meibomian Glands Reveal Common Signature Genes of Meibogenesis. Int J Mol Sci 2019; 20:ijms20184539. [PMID: 31540257 PMCID: PMC6769918 DOI: 10.3390/ijms20184539] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 01/18/2023] Open
Abstract
Meibum is a lipid secretion that is produced by holocrine Meibomian glands (MGs). MGs are a specialized type of sebaceous glands that are embedded in the human eyelids. Chemically, meibum and sebum are different. A detailed characterization of lipidome and transcriptome of MG is required to deconvolute a complex and poorly characterized array of biosynthetic reactions (termed meibogenesis) that lead to formation of meibum. Changes in the composition and quality of meibum have been linked to various ocular disorders, some of which are more prevalent in males, while others in females. To establish the role of gender in meibogenesis in humans, we characterized MG transcriptomes and lipidomes of females and males, and identified signature genes of meibogenesis in both genders. Specimens of MG tissues were subjected to mRNA microarray analyses. Chemical composition of meibum samples was assessed chromatographically and mass spectrometrically. Both targeted and untargeted approaches were used. About 290 signature genes of meibogenesis were identified. The analyses of their expression patterns demonstrated no major differences between the genders. Lipid profiling of major classes of meibomian lipids, such as wax esters, cholesteryl esters, free cholesterol, (O)-acylated omega-hydroxy fatty acids (OAHFA), cholesteryl esters of OAHFA, and triacylglycerols, also demonstrated only minor (and random) differences in these lipids. The results of transcriptomic analyses correlated well with lipidomic data. Taken together, our data imply that in males and females, meibogenesis proceeds in a similar fashion, yielding secretions with similar, highly conserved, compositions. This finding is important for designing novel, gender-independent diagnostic and therapeutic approaches to various MG-related diseases and pathological conditions.
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Affiliation(s)
- Igor A Butovich
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Nita Bhat
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Jadwiga C Wojtowicz
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Wang Z, Wang DH, Park HG, Yan Y, Goykhman Y, Lawrence P, Kothapalli KSD, Brenna JT. Identification of genes mediating branched chain fatty acid elongation. FEBS Lett 2019; 593:1807-1817. [DOI: 10.1002/1873-3468.13451] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 05/03/2019] [Accepted: 05/18/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Zhen Wang
- Department of Food Science Cornell University Ithaca NY USA
- Division of Nutritional Sciences Cornell University Ithaca NY USA
- Dell Pediatric Research Institute and Department of Pediatrics Dell Medical School The University of Texas at Austin TX USA
| | - Dong Hao Wang
- Department of Food Science Cornell University Ithaca NY USA
- Division of Nutritional Sciences Cornell University Ithaca NY USA
- Dell Pediatric Research Institute and Department of Pediatrics Dell Medical School The University of Texas at Austin TX USA
| | - Hui Gyu Park
- Division of Nutritional Sciences Cornell University Ithaca NY USA
- Dell Pediatric Research Institute and Department of Pediatrics Dell Medical School The University of Texas at Austin TX USA
| | - Yuanyuan Yan
- Division of Nutritional Sciences Cornell University Ithaca NY USA
- School of Public Health Shanghai Jiao Tong University School of Medicine China
| | - Yuliya Goykhman
- Division of Nutritional Sciences Cornell University Ithaca NY USA
| | - Peter Lawrence
- Department of Food Science Cornell University Ithaca NY USA
- Division of Nutritional Sciences Cornell University Ithaca NY USA
| | - Kumar S. D. Kothapalli
- Division of Nutritional Sciences Cornell University Ithaca NY USA
- Dell Pediatric Research Institute and Department of Pediatrics Dell Medical School The University of Texas at Austin TX USA
| | - J. Thomas Brenna
- Department of Food Science Cornell University Ithaca NY USA
- Division of Nutritional Sciences Cornell University Ithaca NY USA
- Dell Pediatric Research Institute and Department of Pediatrics Dell Medical School The University of Texas at Austin TX USA
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Gutierrez MDLA, Colman Lerner JE, Giuliani DS, Porta AA, Andrinolo D. Comparative study of tear lipid composition in two human populations with different exposure to particulate matter in La Plata, Argentina. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:6948-6956. [PMID: 30637522 DOI: 10.1007/s11356-019-04134-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 01/02/2019] [Indexed: 06/09/2023]
Abstract
To identify the changes in the lipid profile of the tear film in two human populations exposed to different levels of particulate material, and its relationship with dry eye, by gas chromatography with mass spectrometry (GC-MS) detection. A panel study involving 78 volunteers, who live and work in two locations in Argentina with different pollution levels: urban zone (n = 44) and industrial zone (n = 34). We measured the mean levels of particulate matter (PM) exposure. The tear samples were analyze by gas GC-MS detection and the dry eye was diagnose using Schirmer test, fluorescein breakup time, vital staining with fluorescein and lissamine green, and lid parallel conjunctival folds (LIPCOF). Statistical analysis was performed using Chi-Square, Bartlett's, Mann-Whitney tests, and Multiple Correspondence Analysis. PM10 level was significantly higher in industrial zone than in urban area (p < 0.05). Subjects exposed to higher levels of PM10 in outdoor air presented more presence of fatty acids (FA) of long chain, a higher proportion of saturated fatty acids (SFA), and lower unsaturated fatty acids (UFA), showing a differentiated profile, which may be associated with a PM level. The incidence of dry eye was greater in the industrial zone (p < 0.001), showing in both populations for this pathology higher FA ω-6 levels, which are responsible for the inflammation process. The lipid profile in populations exposed to higher levels of PM10, like the industrial zone, shows a differentiated profile of FA and more incidence of dry eye with higher FA ω-6 levels, which are responsible for the inflammation process.
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Affiliation(s)
- María de Los Angeles Gutierrez
- Programa Ambiental de Extensión Universitaria (PAEU), Facultad de Ciencias Exactas-CONICET, Universidad Nacional de La Plata, 47 y 115, Buenos Aires, Argentina
- Centro de Investigaciones del Medio Ambiente (CIM), CONICET, Facultad de Ciencias Exactas-CONICET, Universidad Nacional de La Plata, 47 y 115, Buenos Aires, Argentina
| | - Jorge Esteban Colman Lerner
- Centro de Investigaciones y desarrollo en ciencias aplicadas (CINDECA), Facultad de Ciencias Exactas-CONICET, CIC-PBA, Universidad Nacional de La Plata, 47 y 115 No. 257, Buenos Aires, Argentina.
| | - Daniela Silvana Giuliani
- Centro de Investigaciones del Medio Ambiente (CIM), CONICET, Facultad de Ciencias Exactas-CONICET, Universidad Nacional de La Plata, 47 y 115, Buenos Aires, Argentina
| | - Atilio Andres Porta
- Centro de Investigaciones del Medio Ambiente (CIM), CONICET, Facultad de Ciencias Exactas-CONICET, Universidad Nacional de La Plata, 47 y 115, Buenos Aires, Argentina
| | - Darío Andrinolo
- Programa Ambiental de Extensión Universitaria (PAEU), Facultad de Ciencias Exactas-CONICET, Universidad Nacional de La Plata, 47 y 115, Buenos Aires, Argentina
- Centro de Investigaciones del Medio Ambiente (CIM), CONICET, Facultad de Ciencias Exactas-CONICET, Universidad Nacional de La Plata, 47 y 115, Buenos Aires, Argentina
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Effects of Lipid Saturation on the Surface Properties of Human Meibum Films. Int J Mol Sci 2018; 19:ijms19082209. [PMID: 30060578 PMCID: PMC6121396 DOI: 10.3390/ijms19082209] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/23/2018] [Accepted: 07/24/2018] [Indexed: 11/28/2022] Open
Abstract
Elevated levels of acyl chain saturation of meibomian lipids are associated with vastly different effects: from enhanced tear film (TF) stability in infants to shortened TF breakup time in meibomian gland disease patients. Thus it is important to study the effect of saturation on the surface properties of human meibum (MGS). Therefore, MGS films (1, 2, 3, 4, 5, 10, 25, 50, 67, and 100% saturation) were spread at the air/water interface of a Langmuir surface balance. The layers’ capability to reorganize during dynamic area changes was accessed via the surface pressure (π)-area (A) compression isotherms and step/relaxation dilatational rheology studies. Film structure was monitored with Brewster angle microscopy. The raise in the % (at ≥10%) of saturation resulted in the formation of stiffer, thicker, and more elastic films at π ≥ 12 mN/m with the effects being proportional to the saturation level. At the same time, at low (≤10 mN/m) π the raise in saturation resulted in altered spreading and heterogeneous structure of MGS layers. The strong impact of saturation on MGS surface properties correlates with our recent spectroscopy study, which demonstrated that saturation induced increase of MGS acyl chain order, phase transition temperature, and cooperativity.
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Jiang X, Wang Y, Lv H, Liu Y, Zhang M, Li X. Efficacy of intra-meibomian gland injection of the anti-VEGF agent bevacizumab for the treatment of meibomian gland dysfunction with lid-margin vascularity. DRUG DESIGN DEVELOPMENT AND THERAPY 2018; 12:1269-1279. [PMID: 29805249 PMCID: PMC5960246 DOI: 10.2147/dddt.s146556] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Purpose To investigate the efficacy of a novel treatment - intra-meibomian gland (MG) injection of the anti-VEGF agent bevacizumab - for MG dysfunction (MGD) with eyelid-margin vascularity. Methods A total of 26 eyes from 13 patients diagnosed with MGD and eyelid-margin vascularity were included in our study. Patients received intra-meibomian gland injections of bevacizumab (150 μL, 2.5 mg/0.1 mL) at multiple sites with a 29 G needle where telangiectasia was severe. The Ocular Surface Disease Index (OSDI), tear film, tear-breakup time (TBUT), eyelid-margin features, MG features, conjunctiva, and corneal staining were assessed at 1 day before injection and 1 week, 1 month, and 3 months after injection. Blood pressure, best-corrected visual acuity, intraocular pressure, and slit lamp examinations were performed to assure the safety of patients at 1 day before and 1 day, 1 week, 1 month, and 3 months after injection. Results Lid-margin vascularity, conjunctival injection, expressed secretion quality, expressivity of the MG, TBUT, corneal staining, and OSDI were significantly improved 1 week, 1 month, and 3 months after injection compared to baseline values. Lid-margin vascularity, conjunctival injection, meibomian gland expressivity, TBUT, and OSDI continued to improve; the greatest improvements were observed at 1 month and sustained for 3 months. Spearman's correlation analysis indicated that age and sex significantly influenced TBUT improvement. Females and older patients tended to have shorter baseline TBUT that followed a different trend from that of males and younger patients during postinjection visits, revealed by subgroup analysis. No local or systemic side effects were observed at follow-up visits. Conclusion This study is the first to explore a novel therapy for MGD - intra-MG injection of the anti-VEGF agent bevacizumab - and it demonstrates that the treatment is effective and safe in eliminating eyelid-margin vascularity, improving MG function and relieving clinical signs and symptoms of MGD.
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Affiliation(s)
- Xiaodan Jiang
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
| | - Yuexin Wang
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
| | - Huibin Lv
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
| | - Yan Liu
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
| | - Mingzhou Zhang
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
| | - Xuemin Li
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
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Abstract
OBJECTIVES The aim of this study was to develop and evaluate, using psychometric approaches, a meibomian gland dysfunction (MGD)-specific questionnaire in noncontact lens wearers. METHODS The MGD subjects were recruited and classified as the MGD dry eye subtype based on accepted tests (e.g., Schein symptom survey, tear breakup time, corneal and conjunctival staining, abnormal meibum or meibomian gland atrophy, and a normal Schirmer test). The MGD questionnaire items were drawn from published and anecdotal sources. The preliminary instrument contained 24 items targeting the frequency and intensity of 12 symptoms. Rasch analysis was used for psychometric evaluation of the survey items. RESULTS Sixty nine MGD subjects completed the survey and clinical testing. Sample severity levels were as follows: none subclinical, 10 minimal, 43 mild, 16 moderate, and none severe. Three iterations of analysis, eliminating INFIT and OUTFIT scores <, and >3.0, and using subject responses reduced the final questionnaire to seven question pairs. Final analysis for the remaining 14 items demonstrated an excellent fit to the Rasch model (e.g., for persons, INFIT MNSQ=0.97; ZSTD=-0.2; OUTFIT MNSQ=0.96; ZSTD=-0.2; item fit statistics were similar). Construct validity also seems good (e.g., correlation to Schein and change with treatment). CONCLUSIONS The MGD-specific instrument is a valid quantitative measure of the symptoms stemming from MGD sufferers. Further research is necessary to determine whether diagnostic efficacy is sufficient to differentiate the MGD dry eye subtype in an independent sample of normals and both major dry eye subtypes exhibiting a broad severity range.
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Hagen KB, Bedi R, Blackie CA, Christenson-Akagi KJ. Comparison of a single-dose vectored thermal pulsation procedure with a 3-month course of daily oral doxycycline for moderate-to-severe meibomian gland dysfunction. Clin Ophthalmol 2018; 12:161-168. [PMID: 29398903 PMCID: PMC5775735 DOI: 10.2147/opth.s150433] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Purpose The aim of this study was to compare the efficacy of a single bilateral 12-minute vectored thermal pulsation (VTP) procedure versus daily oral doxycycline for 3 months for moderate-to-severe meibomian gland dysfunction (MGD). Methods This prospective, randomized, parallel-group, single-masked study included 28 subjects who received either a single-dose VTP or 3 months of doxycycline treatment. At baseline and 3 months post treatment, all subjects were evaluated for the following: dry eye symptoms with a standard dry eye questionnaire (the Standard Patient Evaluation for Eye Dryness [SPEED]), meibomian gland (MG) function by counting the number of glands yielding liquid secretion with the MG evaluator (MGE), tear breakup time (TBUT) and corneal and conjunctival staining. Results In the VTP group, at 3 months, there was a significant improvement in MG function (4.00±1.47 to 7.73±5.53), SPEED score (11.00±3.30 to 5.42±2.15), TBUT (6.26±2.01 to 8.44±1.81), corneal staining (0.38±0.50 to 0.12±0.33) and conjunctival staining (1.69±1.93 to 0.62±0.85). In the doxycycline group, there was a significant improvement in MG function (4.63±1.41 to 10.63±5.91), SPEED score (13.42±4.17 to 9.42±5.47) and conjunctival staining (2.38±1.88 to 1.13±1.51), but the improvement in TBUT (6.90±2.56 to 7.59±2.03) and corneal staining (0.21±0.41 to 0.13±0.34) was not statistically significant (p=0.262 and p=0.414, respectively). At 3 months, SPEED score was significantly better in the VTP group (p<0.05); other parameters were comparable between the two groups. Conclusion A single 12-minute bilateral VTP procedure was significantly more effective than the 3-month daily course of oral doxycycline at improving the dry eye symptoms secondary to MGD. A single 12-minute VTP treatment was at least as effective as a dose of doxycycline for 3 months, in improving MG function and all measured signs of MGD. Given the minimal risk profile of the single VTP procedure over long-term doxycycline use, a single VTP presents a favorable alternative to long-term antibiotic use.
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Affiliation(s)
| | - Raman Bedi
- Iris Advanced Eye Centre, Chandigarh, India
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Abstract
The subcommittee reviewed the prevalence, incidence, risk factors, natural history, morbidity and questionnaires reported in epidemiological studies of dry eye disease (DED). A meta-analysis of published prevalence data estimated the impact of age and sex. Global mapping of prevalence was undertaken. The prevalence of DED ranged from 5 to 50%. The prevalence of signs was higher and more variable than symptoms. There were limited prevalence studies in youth and in populations south of the equator. The meta-analysis confirmed that prevalence increases with age, however signs showed a greater increase per decade than symptoms. Women have a higher prevalence of DED than men, although differences become significant only with age. Risk factors were categorized as modifiable/non-modifiable, and as consistent, probable or inconclusive. Asian ethnicity was a mostly consistent risk factor. The economic burden and impact of DED on vision, quality of life, work productivity, psychological and physical impact of pain, are considerable, particularly costs due to reduced work productivity. Questionnaires used to evaluate DED vary in their utility. Future research should establish the prevalence of disease of varying severity, the incidence in different populations and potential risk factors such as youth and digital device usage. Geospatial mapping might elucidate the impact of climate, environment and socioeconomic factors. Given the limited study of the natural history of treated and untreated DED, this remains an important area for future research.
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Dyslipidemia and its Association with Meibomian Gland Dysfunction: A Systematic Review. Int Ophthalmol 2017; 38:1809-1816. [PMID: 28688025 DOI: 10.1007/s10792-017-0633-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 06/27/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE To perform a systematic review of the literature examining the association between meibomian gland dysfunction (MGD) and dyslipidemia. METHODS A systematic literature search was performed using the Medline database. A total of four studies directly relevant to our search are reviewed here. RESULTS In a series of four studies, all but one found that the prevalence of dyslipidemia was significantly higher in those with MGD compared to those without. Factors such as age, total cholesterol, LDL, HDL, and triglycerides demonstrated a significant association whereas sex, BMI, serum creatinine, and serum glucose did not. Various subsets within the MGD group, such as males between the ages of 24-64, were found to have higher total cholesterol levels compared to controls, highlighting the association of dyslipidemia with sex and age. CONCLUSION While each study carried its own limitations preventing a causal relationship from being established, it is evident that a strong positive correlation exists between dyslipidemia and MGD. As such, eye care practitioners, through the detection of MGD, may be identifying patients with dyslipidemia who were previously believed to have normal serum lipid profiles. This may imply that eye care providers have a role in detecting a well-known risk factor for cardiovascular disease. Additionally, if prospective studies can demonstrate a temporal relationship with MGD preceding dyslipidemia, clinicians could consider lipid-lowering agents as management for both conditions.
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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: 83] [Impact Index Per Article: 11.9] [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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Soria J, Acera A, Durán JA, Boto-de-Los-Bueis A, Del-Hierro-Zarzuelo A, González N, Reigada R, Suárez T. The analysis of human conjunctival epithelium proteome in ocular surface diseases using impression cytology and 2D-DIGE. Exp Eye Res 2017; 167:31-43. [PMID: 28336260 DOI: 10.1016/j.exer.2017.03.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 12/01/2016] [Accepted: 03/17/2017] [Indexed: 12/30/2022]
Abstract
Conjunctival impression cytology samples from patients with meibomian gland dysfunction (MGD), dry eye (DE), and healthy subjects (CT) were collected for determination of the degree of squamous metaplasia (SM) by PAS-hematoxylin staining and for comparative proteomic analyses by 2D-DIGE. The protein spots with discriminant expression were identified by MALDI-TOF/TOF mass spectrometry. Three independent statistical studies were conducted: i). Analysis of differential protein expression between study groups: We observed increased expression of proteins S100A4, S100A8, retinal dehydrogenase-1, peroxiredoxin-1, annexin-A1, annexin-A2, α-enolase, and glutathione S-transferase-P in DE, whereas the highest expression of peroxiredoxin-6, actin cytoplasmic-1, peroxiredoxin-2, and heat shock protein HSP-90-α was observed in MGD; ii). Correlation between changes in the proteome profile and the grade of SM: The expression of 5 different cytokeratins (KRT1, KRT4, KRT8, KRT10, and KRT13) correlated with the degree of SM; iii). Proteome profile differences between pathological and CT groups: An overall proteome analysis revealed upregulation of 9 proteins in the pathological groups (Annexin-A1, α-enolase, Annexin-A2, S100A8, cytokeratin-1, Peroxiredoxin-2 and Leukocyte elastase inhibitor) and downregulation of 2 proteins (Galectin-3 and Lipocalin-1). In conclusion, a sensitive proteomic approach to study conjunctival tissue collected from minimally invasive impression cytology was implemented. Differential proteomics analyses showed that in comparison with the MGD, the DE patients presented higher overexpression of proteins related to antimicrobial defense, tissue-damage response, and regulation of body fluid secretions. Changes in MGD proteome were associated with oxidative stress and anti-apoptotic processes. We found a correlation between the grade of SM and expression of proteins associated with cytoskeleton and keratinization. The studied pathological groups shared elements related to the defense and inflammatory responses. Dot blot assays of proteins ANXA1, S100A8, and S100A4 validated the proteomic results obtained from 2D-DIGE experiments and confirmed the correlation between the expression of these proteins and the clinical parameters.
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Affiliation(s)
- Javier Soria
- Bioftalmik Applied Research, Bizkaia Science and Technology Park, Building 612, E-48160 Derio, Bizkaia, Spain
| | - Arantxa Acera
- Bioftalmik Applied Research, Bizkaia Science and Technology Park, Building 612, E-48160 Derio, Bizkaia, Spain
| | - Juan A Durán
- Instituto Clínico Quirúrgico de Oftalmología (ICQO), Virgen de Begoña Nº 34, E-48006 Bilbao, Bizkaia, Spain; Department of Ophthalmology, School of Medicine, University of the Basque Country (UPV/EHU), Leioa, Bizkaia, Spain
| | | | | | - Nerea González
- Bioftalmik Applied Research, Bizkaia Science and Technology Park, Building 612, E-48160 Derio, Bizkaia, Spain
| | - Rebeca Reigada
- Bioftalmik Applied Research, Bizkaia Science and Technology Park, Building 612, E-48160 Derio, Bizkaia, Spain
| | - Tatiana Suárez
- Bioftalmik Applied Research, Bizkaia Science and Technology Park, Building 612, E-48160 Derio, Bizkaia, Spain.
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Wolkoff P. External eye symptoms in indoor environments. INDOOR AIR 2017; 27:246-260. [PMID: 27444579 DOI: 10.1111/ina.12322] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 07/19/2016] [Indexed: 05/22/2023]
Abstract
Eye irritation, for example dry or irritated eyes, is generally among top three reported symptoms in office-like environments, in particular among workplaces with cognitive demanding visual display unit (VDU) work. The symptoms are especially among middle and advanced ages and particularly among women more than men. The symptoms are also among the most commonly reported complaints in the eye clinic. To be in a position to interpret the high prevalence of eye symptoms, a multidisciplinary and integrated approach is necessary that involves the external eye physiology (separate from internal eye effects), eye diseases (evaporative dry eye (DE), aqueous-deficient DE, and gland dysfunctions), and risk factors that aggravate the stability of precorneal tear film (PTF) resulting in hyperosmolarity and initiation of inflammatory reactions. Indoor environmental, occupational and personal risk factors may aggravate the PTF stability; factors such as age, contact lenses, cosmetics, diet, draft, gender, low humidity and high temperature, medication, outdoor and combustion pollutants, and VDU work. Psychological stressors may further influence the reporting behavior of eye symptoms. The impact of the risk factors may occur in a combined and exacerbating manner.
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Affiliation(s)
- P Wolkoff
- National Research Centre for the Working Environment, Copenhagen, Denmark
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Proper balance of omega-3 and omega-6 fatty acid supplements with topical cyclosporine attenuated contact lens-related dry eye syndrome. Inflammopharmacology 2016; 24:389-396. [DOI: 10.1007/s10787-016-0291-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 10/08/2016] [Indexed: 10/20/2022]
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Hagan S, Martin E, Enríquez-de-Salamanca A. Tear fluid biomarkers in ocular and systemic disease: potential use for predictive, preventive and personalised medicine. EPMA J 2016; 7:15. [PMID: 27413414 PMCID: PMC4942926 DOI: 10.1186/s13167-016-0065-3] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/03/2016] [Indexed: 11/10/2022]
Abstract
In the field of predictive, preventive and personalised medicine, researchers are keen to identify novel and reliable ways to predict and diagnose disease, as well as to monitor patient response to therapeutic agents. In the last decade alone, the sensitivity of profiling technologies has undergone huge improvements in detection sensitivity, thus allowing quantification of minute samples, for example body fluids that were previously difficult to assay. As a consequence, there has been a huge increase in tear fluid investigation, predominantly in the field of ocular surface disease. As tears are a more accessible and less complex body fluid (than serum or plasma) and sampling is much less invasive, research is starting to focus on how disease processes affect the proteomic, lipidomic and metabolomic composition of the tear film. By determining compositional changes to tear profiles, crucial pathways in disease progression may be identified, allowing for more predictive and personalised therapy of the individual. This article will provide an overview of the various putative tear fluid biomarkers that have been identified to date, ranging from ocular surface disease and retinopathies to cancer and multiple sclerosis. Putative tear fluid biomarkers of ocular disorders, as well as the more recent field of systemic disease biomarkers, will be shown.
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Affiliation(s)
- Suzanne Hagan
- Department of Life Sciences, Vision Sciences, Glasgow Caledonian University (GCU ), G4 0BA Glasgow, Scotland, UK
| | - Eilidh Martin
- Department of Life Sciences, Vision Sciences, Glasgow Caledonian University (GCU ), G4 0BA Glasgow, Scotland, UK
| | - Amalia Enríquez-de-Salamanca
- Institute of Applied Ophthalmobiology (IOBA), University of Valladolid, Valladolid, Spain ; Biomedical Research Networking Centre in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Valladolid, Spain
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Arita R, Mori N, Shirakawa R, Asai K, Imanaka T, Fukano Y, Nakamura M. Linoleic acid content of human meibum is associated with telangiectasia and plugging of gland orifices in meibomian gland dysfunction. Exp Eye Res 2016; 145:359-362. [DOI: 10.1016/j.exer.2016.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 02/07/2016] [Accepted: 02/22/2016] [Indexed: 10/22/2022]
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Kılıç Müftüoğlu İ, Aydın Akova Y. Clinical Findings, Follow-up and Treatment Results in Patients with Ocular Rosacea. Turk J Ophthalmol 2016; 46:1-6. [PMID: 27800249 PMCID: PMC5076302 DOI: 10.4274/tjo.48902] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 04/07/2015] [Indexed: 12/02/2022] Open
Abstract
Objectives: To report the clinical features, treatment options and complications in patients with ocular rosacea. Materials and Methods: The records of 48 eyes of 24 patients with ocular rosacea were retrospectively reviewed. Patients’ ocular signs and symptoms were scored between 1 and 4 points according to disease severity; tear film break-up time (BUT) and Schirmer’s test results were recorded before and after the treatment. Preservative-free artificial tears, topical antibiotic eye drops/ointments, short-term topical corticosteroids, topical 0.05% cyclosporine and oral doxycycline treatment were applied as a standard therapy to all patients. Additional treatments were given as needed. Complications were recorded. Results: Twenty-four patients with a mean age of 48.5±35.4 (32-54) years were followed for a mean 15±9.4 (8-36) months. Ocular findings included meibomitis in 100% of cases, anterior blepharitis in 83% (40 eyes), punctate keratopathy in 67% (32 eyes), chalazia in 50% (24 eyes), corneal neovascularization in 50% (24 eyes) and subepithelial infiltrates in 16.6% (8 eyes). Significant improvement of symptoms and clinical findings were achieved in all patients with treatment. The increases in Schirmer’s test and BUT were 3.3±1.5 and 4.5±2.8, respectively (p<0.05). Descemetocele and small corneal perforation occurred in 2 eyes; re-epithelialization was achieved in both eyes with tissue adhesive application (1 eye) and additional amniotic membrane transplantation (1 eye). Four eyes of three patients showed significant regression of corneal neovascularization with topical bevacizumab therapy. Conclusion: Ocular rosacea may present with a variety of ophthalmic signs. It is possible to control the ophthalmic disease with appropriate therapeutic modalities including topical corticosteroids, topical cyclosporine and systemic doxycycline.
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Abstract
PURPOSE To determine whether tear collection by flushing the ocular surface with saline (flush tears) or collection by stimulation (reflex tears) can be used as an alternative to basal tear collection for the identification and quantification of lipids in the tear film. METHODS Tear samples were collected from 10 participants with no history of ocular surface disease or contact lens wear. Up to 10 μl of basal, reflex, and flush tear samples were collected from each eye using a microcapillary tube on three occasions with the order of methods randomized and allowing at least 24 hours between each collection method. Lipids were quantified from each tear sample using nano-electrospray ionization tandem mass spectrometry. RESULTS Total lipids significantly differed in their concentration (pmol/μl) and mole % with each collection technique. Cholesterol esters [mean % (SE)] formed the major component of the total lipidome in basal [54.8% (3.1)], reflex [35.7% (6.4)], and flush [33.0% (3.1)] tear samples. However, the mole % of each lipid class substantially varied with each tear collection method. Nonpolar lipids, including cholesterol, wax esters, and triacylglycerols, dominated the tear lipidome in basal [92.8% (1.9)], reflex [71.8% (7.9)], and flush [83.6% (3.8)] tear samples. However, the mole % of phospholipids in reflex [27.5% (8.1)] and flush [15.8% (3.8)] tear samples was higher (p = 0.005) than that in basal tears [5.4% (2.0)]. CONCLUSIONS Flush or reflex tears did not have similar lipid profiles in either concentration or in mole % to basal tears. It is recommended that basal tears are used for tear lipid analysis as the reflex or flush tears contain very low levels of most lipid components.
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Evaluation of an eyelid warming device (Blephasteam) for the management of ocular surface diseases in France: the ESPOIR study. J Fr Ophtalmol 2014; 37:763-72. [PMID: 25282620 DOI: 10.1016/j.jfo.2014.06.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/02/2014] [Accepted: 06/05/2014] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Eyelid hygiene, including massage and warm compresses, is an important part of the treatment and prevention of Meibomian gland dysfunction (MGD). Although effective, it requires active participation of the patient and lacks standardisation. Blephasteam is a medical device designed to warm and humidify the eyelid with heating glasses, in order to liquify meibum, thus relieving symptoms and preventing relapse. MATERIALS AND METHODS The ESPOIR study (Evaluation of the Satisfaction of Patients with Management of Ocular Surface Diseases) presented herein was designed to evaluate the safety and efficacy of this medical device in patients with MGD. A total of 28 French centers participated in the study. One hundred and two patients presenting with symptomatic dysfunction or Meibomian-related dry eye underwent two sessions per day with the eyelid warming device and recorded diary entries on a number of parameters every 2 days for the first week and then weekly for the remaining 2 weeks. Patients were assessed on days 0 and 21. RESULTS Symptomatology, as recorded on a visual analogue scale (VAS) by the investigator (the primary efficacy variable) was significantly (P<0.001) improved at the end of the study (59.97, 95% CI 55.64-64.30 vs. 39.71, 95% CI 34.78-44.65 on Days 0 and 21 respectively), as was the mean symptoms score (mean decrease of 19.93 ± 22.15 VAS units; P<0.001), hyperemia score (-1.57 ± 1.96 and -1.45 ± 1.85; P<0.001, in the worse and contralateral eye respectively), and quality of meibum (mean -4.03 ± 3.08; P<0.001 and -3.32 ± 3.20; P<0.01, in the worse and contralateral eye respectively). More than twice as many reported their symptoms had improved or disappeared compared with those whose symptoms had not changed or had worsened. Global symptomatology, as assessed by the patients, declined throughout the study, and a large majority of patients were satisfied or very satisfied with the treatment. Clear vision and blinking were not impaired during use of the eyelid warming device, which insures proper spreading of the tear film, and patients were able to continue daily activities such as reading and watching television. No adverse events were reported, and there were no changes in intraocular pressure or visual acuity. Safety was rated as satisfactory or very satisfactory by more than 95% of the investigators. CONCLUSION The study suggests that the eyelid warming device is safe and effective in reducing ocular discomfort and symptoms in MGD.
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Tahiri Joutei Hassani R, Liang H, El Sanharawi M, Brasnu E, Kallel S, Labbé A, Baudouin C. En-face optical coherence tomography as a novel tool for exploring the ocular surface: a pilot comparative study to conventional B-scans and in vivo confocal microscopy. Ocul Surf 2014; 12:285-306. [PMID: 25284774 DOI: 10.1016/j.jtos.2014.02.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 02/03/2014] [Accepted: 02/06/2014] [Indexed: 12/01/2022]
Abstract
PURPOSE To explore the potential of spectral-domain optical coherence tomography (SD-OCT) using the en-face technology for the imaging of ocular surface diseases and to correlate the findings with in vivo confocal microscopy (IVCM) images. PATIENTS AND METHODS 113 eyes of 75 subjects with various ocular surface diseases were investigated with the RTVue(®) anterior-segment en face OCT. En face OCT images were compared to B-scan OCT and IVCM images. RESULTS Patients with corneal dystrophies, corneal deposits, keratitis, pterygium, conjunctivochalasis, or ocular surface squamous neoplasia and patients who underwent lamellar corneal surgeries were included. En-face OCT images showed ocular surface tissue changes that were not discernible using conventional B-scan OCT. Nevertheless, there was a good correlation with IVCM analysis. Compared with IVCM, the major advantages of en-face OCT included easy operation and rapid image acquisition, with minimal operator experience required. In addition, the non-contact method avoided patient discomfort and external pressure on the globe, which was especially useful in patients with corneal dystrophies, ulcers, or corneal abscesses. Although the resolution of en-face OCT was lower than that of IVCM, it allowed useful overall visualization of corneal lesions due to the larger areas analyzed. CONCLUSION En-face SD-OCT is a novel, valuable tool to assess a wide variety of ocular surface diseases. It can provide additional information and new insight into different ocular surface conditions with no corneal contact.
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Affiliation(s)
- Rachid Tahiri Joutei Hassani
- Department of Ophthalmology, 3 Quinze-Vingts National Ophthalmology Hospital, Paris; Center for Clinical Investigations INSERM 503, Quinze-Vingts National Eye Center, Paris
| | - Hong Liang
- Department of Ophthalmology, 3 Quinze-Vingts National Ophthalmology Hospital, Paris; Center for Clinical Investigations INSERM 503, Quinze-Vingts National Eye Center, Paris; INSERM, U968, Paris, F-75012, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris F-75012; CNRS, UMR_7210, Paris F-75012, France
| | - Mohamed El Sanharawi
- Department of Ophthalmology, 3 Quinze-Vingts National Ophthalmology Hospital, Paris
| | - Emmanuelle Brasnu
- Department of Ophthalmology, 3 Quinze-Vingts National Ophthalmology Hospital, Paris; Center for Clinical Investigations INSERM 503, Quinze-Vingts National Eye Center, Paris
| | - Sofiene Kallel
- Department of Ophthalmology, 3 Quinze-Vingts National Ophthalmology Hospital, Paris; Department of Ophthalmology, Ambroise Paré Hospital, AP-HP, UFR Paris-île de France Ouest, University of Versailles Saint-Quentin-en-Yvelines, Versailles, France
| | - Antoine Labbé
- Department of Ophthalmology, 3 Quinze-Vingts National Ophthalmology Hospital, Paris; Center for Clinical Investigations INSERM 503, Quinze-Vingts National Eye Center, Paris; INSERM, U968, Paris, F-75012, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris F-75012; CNRS, UMR_7210, Paris F-75012, France; Department of Ophthalmology, Ambroise Paré Hospital, AP-HP, UFR Paris-île de France Ouest, University of Versailles Saint-Quentin-en-Yvelines, Versailles, France
| | - Christophe Baudouin
- Department of Ophthalmology, 3 Quinze-Vingts National Ophthalmology Hospital, Paris; Center for Clinical Investigations INSERM 503, Quinze-Vingts National Eye Center, Paris; INSERM, U968, Paris, F-75012, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris F-75012; CNRS, UMR_7210, Paris F-75012, France; Department of Ophthalmology, Ambroise Paré Hospital, AP-HP, UFR Paris-île de France Ouest, University of Versailles Saint-Quentin-en-Yvelines, Versailles, France.
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Mori N, Fukano Y, Arita R, Shirakawa R, Kawazu K, Nakamura M, Amano S. Rapid identification of fatty acids and (O-acyl)-ω-hydroxy fatty acids in human meibum by liquid chromatography/high-resolution mass spectrometry. J Chromatogr A 2014; 1347:129-36. [DOI: 10.1016/j.chroma.2014.04.082] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 04/02/2014] [Accepted: 04/22/2014] [Indexed: 11/16/2022]
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Muselier-Mathieu A, Bron AM, Mathieu B, Souchier M, Brignole-Baudouin F, Acar N, Brétillon L, Creuzot-Garcher C. Ocular surface assessment in soft contact lens wearers; the contribution of tear osmolarity among other tests. Acta Ophthalmol 2014; 92:364-9. [PMID: 23506409 DOI: 10.1111/aos.12103] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To determine whether tear osmolarity contributes to the assessment of the ocular surface in soft contact lens (CL) wearers. METHODS Prospective, case-control series in 44 CL wearers (28 tolerant and 16 intolerant) and 34 healthy subjects. Every patient underwent a thorough ophthalmic examination with a tear osmolarity test (TearLab System), conjunctival impression cytology and meibomian lipid sampling. Symptoms, break-up time (BUT), tear osmolarity, conjunctival expression of HLA-DR and meibomian fatty acid composition were evaluated. RESULTS Tear osmolarity did not differ between controls and CL wearers (p= 0.23). Flow cytometry results expressed in antibody-binding capacity (ABC) units and percentage of positive cells revealed a significant difference between the intolerant CL wearer group and the control group (p< 0.0001). Comparisons between tolerant and intolerant CL wearers showed only a significant difference for mean fluorescence levels expressed in ABC units (p< 0.0001). The BUT was significantly shorter in intolerant and tolerant CL wearers subjects than in healthy subjects (p< 0.0001), whereas there was no significant difference in meibomian fatty acid composition (p= 0.99) between the two groups. CONCLUSION Contact lens wear is responsible for ocular surface alterations whose patterns are very similar to those reported in early dry-eye syndrome. However, tear osmolarity was not modified in these selected CL wearers. The yield of tear osmolarity with TearLab™ in assessing ocular surface disorders in CL wearers deserves further investigation.
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Affiliation(s)
- Aurore Muselier-Mathieu
- Department of Ophthalmology University Hospital, Dijon, FranceLaboratory of Toxicology, Faculty of Pharmaceutical and Biological Sciences, University of Paris-5 René Descartes, Paris, FranceEye and Nutrition Research Group, Centre des Sciences du Goût et de l'Alimentation, UMR 1324 INRA, 6265 CNRS, University of Burgundy, Dijon, France
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Butovich IA, Lu H, McMahon A, Ketelson H, Senchyna M, Meadows D, Campbell E, Molai M, Linsenbardt E. Biophysical and morphological evaluation of human normal and dry eye meibum using hot stage polarized light microscopy. Invest Ophthalmol Vis Sci 2014; 55:87-101. [PMID: 24282231 DOI: 10.1167/iovs.13-13355] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To study melting characteristics and the morphology of human and mouse meibum. METHODS Hot stage cross-polarized light microscopy (HSPM) and immunohistochemical approaches were used. RESULTS Isolated human meibum, and meibum of mice (either isolated or within the meibomian ducts of mice), were found to be in liquid-crystal state at physiological temperatures. Melting of both types of meibum started at approximately 10°C and was completed at approximately 40°C. Melting curves of isolated meibum and meibum inside the meibomian ducts were multiphasic with at least two or three clearly defined phase transition temperatures, typically at approximately 12 ± 2°C (minor transition), 21 ± 3°C, and 32 ± 3°C, regardless the source of meibum. Melting was highly cooperative in nature. Samples of abnormal human meibum collected from dry eye patients with meibomian gland dysfunction often showed an increased presence of nonlipid, nonmelting, nonbirefringent, chloroform-insoluble inclusions of a protein nature. The inclusions were positively stained for cytokeratins. The presence of these inclusions was semiquantitatively characterized using a newly proposed 0 to 4 scale. In the presence of large amounts of these inclusions, melting characteristics of meibum and its structural integrity were altered. CONCLUSIONS HSPM is an effective tool that is suitable for biophysical and morphological evaluation of meibum. Morphological properties and melting characteristics of human meibum were found to be similar to those of mice. Abnormal meibum of many dry eye patients contained large quantities of nonlipid, protein-like inclusions, which were routinely absent in meibum of normal controls.
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Affiliation(s)
- Igor A Butovich
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas
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Suhalim JL, Parfitt GJ, Xie Y, De Paiva CS, De Pavia CS, Pflugfelder SC, Shah TN, Potma EO, Brown DJ, Jester JV. Effect of desiccating stress on mouse meibomian gland function. Ocul Surf 2014; 12:59-68. [PMID: 24439047 PMCID: PMC3896889 DOI: 10.1016/j.jtos.2013.08.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 07/30/2013] [Accepted: 08/13/2013] [Indexed: 11/25/2022]
Abstract
PURPOSE Mice exposed to standardized desiccating environmental stress to induce dry eye-like symptoms have been used as a model to study the underlying mechanisms of evaporative dry eye. While studies have shown marked inflammatory and immune changes, the effect of such stress on meibomian gland function remains largely unknown. We sought to evaluate the effects of desiccating stress on meibocyte proliferation and meibum quality. METHODS Ten mice were treated with scopolamine and subjected to a drafty low humidity environment (30-35%). Five and ten days after treatment, eyelids were harvested and cryosections stained with Ki67 antibody to identify cycling cells. Sections were also imaged using stimulated Raman scattering (SRS) microscopy to characterize the gland compositional changes by detecting the vibrational signatures of methylene (lipid) and amide-I (protein). RESULTS Desiccating stress caused a 3-fold increase in basal acinar cell proliferation from 18.3 ± 11.1% in untreated mice to 64.4 ± 19.9% and 66.6 ± 13.4% after 5 and 10 days exposure, respectively (P < .001). In addition, SRS analysis showed a wider variation in the protein-to-lipid ratio throughout the gland, suggesting alterations in meibocyte differentiation and lipid synthesis. CONCLUSIONS These data are consistent with a model that a desiccating environment may have a direct effect on meibomian gland function, leading to a significant increase in basal acinar cell proliferation, abnormal meibocyte differentiation, and altered lipid production.
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Affiliation(s)
- Jeffrey L Suhalim
- Gavin Herbert Eye Institute, Irvine, CA, USA; Beckman Laser Institute and Medical Clinic, Irvine, CA, USA; Department of Biomedical Engineering, University of California, Irvine, CA, USA
| | | | - Yilu Xie
- Gavin Herbert Eye Institute, Irvine, CA, USA
| | | | - Cintia S De Pavia
- Ocular Surface Center, Department of Ophthalmology, Baylor College of Medicine, Houston, TX, USA
| | - Stephen C Pflugfelder
- Ocular Surface Center, Department of Ophthalmology, Baylor College of Medicine, Houston, TX, USA
| | | | - Eric O Potma
- Beckman Laser Institute and Medical Clinic, Irvine, CA, USA
| | | | - James V Jester
- Gavin Herbert Eye Institute, Irvine, CA, USA; Department of Biomedical Engineering, University of California, Irvine, CA, USA.
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Mudgil P, Borchman D, Yappert MC, Duran D, Cox GW, Smith RJ, Bhola R, Dennis GR, Whitehall JS. Lipid order, saturation and surface property relationships: A study of human meibum saturation. Exp Eye Res 2013; 116:79-85. [DOI: 10.1016/j.exer.2013.08.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 08/08/2013] [Accepted: 08/15/2013] [Indexed: 12/01/2022]
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Lam SM, Tong L, Reux B, Lear MJ, Wenk MR, Shui G. Rapid and sensitive profiling of tear wax ester species using high performance liquid chromatography coupled with tandem mass spectrometry. J Chromatogr A 2013; 1308:166-71. [DOI: 10.1016/j.chroma.2013.08.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Revised: 08/05/2013] [Accepted: 08/05/2013] [Indexed: 02/01/2023]
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Chen J, Green KB, Nichols KK. Quantitative profiling of major neutral lipid classes in human meibum by direct infusion electrospray ionization mass spectrometry. Invest Ophthalmol Vis Sci 2013; 54:5730-53. [PMID: 23847307 DOI: 10.1167/iovs.12-10317] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The purpose of this investigation was to better understand lipid composition in human meibum. METHODS Intact lipids in meibum samples were detected by direct infusion electrospray ionization mass spectrometry (ESI-MS) analysis in positive detection mode using sodium iodide (NaI) as an additive. The peak intensities of all major types of lipid species, that is, wax esters (WEs), cholesteryl esters (CEs), and diesters (DEs) were corrected for peak overlapping and isotopic distribution; an additional ionization efficiency correction was performed for WEs and CEs, which was simplified by the observation that the corresponding ionization efficiency was primarily dependent on the specific lipid class and saturation degree of the lipids while independent of the carbon chain length. A set of WE and CE standards was spiked in meibum samples for ionization efficiency determination and absolute quantitation. RESULTS The absolute amount (μmol/mg) for each of 51 WEs and 31 CEs in meibum samples was determined. The summed masses for 51 WEs and 31 CEs accounted for 48 ± 4% and 40 ± 2%, respectively, of the total meibum lipids. The mass percentages of saturated and unsaturated species were determined to be 75 ± 2% and 25 ± 1% for CEs and 14 ± 1% and 86 ± 1% for WEs. The profiles for two types of DEs were also obtained, which include 42 α,ω Type II DEs, and 21 ω Type I-St DEs. CONCLUSIONS Major neutral lipid classes in meibum samples were quantitatively profiled by ESI-MS analysis with NaI additive.
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Affiliation(s)
- Jianzhong Chen
- Applied Biotechnology Branch, Air Force Research Laboratory, Dayton, Ohio, USA.
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Abstract
Human meibomian gland secretions (MGS, or meibum) are formed from a complex mixture of lipids of different classes such as wax esters, cholesteryl esters, (O-acyl)-ω-hydroxy fatty acids (OAHFA) and their esters, acylglycerols, diacylated diols, free fatty acids, cholesterol, and a smaller amount of other polar and nonpolar lipids, whose chemical nature and the very presence in MGS have been a matter of intense debates. The purpose of this review is to discuss recent results that were obtained using different experimental techniques, estimate limitations of their usability, and discuss their biochemical, biophysical, and physiological implications. To create a lipid map of MGS and tears, the results obtained in the author's laboratory were integrated with available information on chemical composition of MGS and tears. The most informative approaches that are available today to researchers, such as HPLC-MS, GC-MS, and proton NMR, are discussed in details. A map of the meibomian lipidome (as it is seen in reverse phase liquid chromatography/mass spectrometry experiments) is presented. Directions of future efforts in the area are outlined.
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Affiliation(s)
- Igor A Butovich
- Department of Ophthalmology and the Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA.
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