Hyperglycemia Induces Meibomian Gland Dysfunction.
Ontology highlight
ABSTRACT: Purpose
Patients diagnosed with diabetes are inclined to have abnormalities on stability of tear film and disorder of meibomian gland (MG). This study aims to explore the pathological change of MG induced by diabetes in a rat model.Methods
Sprague-Dawley (SD) rats were intraperitoneally injected with streptozotocin (STZ) to establish a diabetic animal model. Lipid accumulation in MG was detected by Oil Red O staining and LipidTox staining. Cell proliferation status was determined by Ki67 and P63 immunostaining, whereas cell apoptosis was confirmed by TUNEL assay. Gene expression of inflammatory cytokines and adhesion molecules IL-1α, IL-1β, ELAM1, ICAM1, and VCAM1 were detected by RT-PCR. Activation of ERK, NF-κB, and AMPK signaling pathways was determined by Western Blot analysis. Oxidative stress-related factors NOX4, 4HNE, Nrf2, HO-1, and SOD2 were detected by immunostaining or Western Blot analysis. Tom20 and Tim23 immunostaining and transmission electron microscopy were performed to evaluate the mitochondria functional and structure change.Results
Four months after STZ injection, there was acini dropout in MG of diabetic rats. Evident infiltration of inflammatory cells, increased expression of inflammatory factors, and adhesion molecules, as well as activated ERK and NF-κB signaling pathways were identified. Oxidative stress of MG was evident in 4-month diabetic rats. Phospho-AMPK was downregulated in MG of 2-month diabetic rats and more prominent in 4-month rats. After metformin treatment, phospho-AMPK was upregulated and the morphology of MG was well maintained. Moreover, inflammation and oxidative stress of MG were alleviated after metformin intervention.Conclusions
Long-term diabetes may lead to Meibomian gland dysfunction (MGD). AMPK may be a therapeutic target of MGD induced by diabetes.
SUBMITTER: Guo Y
PROVIDER: S-EPMC8802017 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:PurposeTo investigate the indirect effects of intense pulsed light (IPL) on morphological and pathological changes of the meibomian glands (MGs) in apolipoprotein E knockout (ApoE-/- ) mice and explore the underlying mechanisms.MethodsApoE-/- mice were treated with or without IPL three times below the lower eyelids and MGs were not directly exposed to irradiation. The eyelids and ocular surface were observed under a stereoscope. The morphology of MGs was examined by photographing and hematoxylin and eosin staining. Lipid droplets in MGs were examined by Oil Red O staining. The ultrastructure of meibocytes and mitochondria was observed under transmission electron microscopy. The relative gene and protein expression in MGs of upper eyelids was determined by immunostaining, Western blot, and qRT-PCR.ResultsThree IPL treatments decreased the toothpaste-like plugging of orifices and thickening and irregularity of the upper and lower eyelid margins in ApoE-/- mice. The morphology of some MGs improved after IPL treatments, accompanied by increased proliferation of acinar basal cells and decreased ductal keratinization. Furthermore, the accumulation of hyperchromatic lipid droplets in the acini increased, and the lipid droplets distributed in the cells around the acini were round and small. Compared with untreated ApoE-/- mice, oxidative stress and apoptosis were downregulated by IPL treatment, accompanied by the improvements in mitochondrial structure. Further research showed that IPL treatments reduced the levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-17A, IL-6 in MGs and inactivated nuclear factor kappa B (NF-κ B).ConclusionCollectively, the results demonstrate that indirect effects of IPL can improve the structure and function of MGs and mitigate the progression of MGD, which may be related to the indirect effects of photobiomodulation.
| S-EPMC9201038 | biostudies-literature
Project description:The aim of this study was to use swept-source anterior segment optical coherence tomography (OCT) to explore imaging the meibomian gland openings and to identify their in vivo characteristics in patients with obstructive meibomian gland dysfunction (MGD) and healthy participants. We enrolled 49 patients with MGD and 54 health controls in this case-control study. Each participant underwent slit-lamp examination, meibography, and OCT scanning. Sixteen patients with MGD underwent a repeat OCT examination after eyelid massage. The outcome measures included determinations of meibomian gland openings (orifices and terminal ducts) from OCT images and comparisons of the meibomian openings between patients with MGD and normal controls before and after meibomian gland massage. Using the same OCT scanning model, the number of visible orifices of the meibomian glands was similar between eyes with MGD and normal eyes (9.2 ± 2.3 vs. 9.7 ± 2.4). The mean diameter of the terminal ducts in patients with MGD was larger (120.22 ± 27.92 µm vs. 100.96 ± 20.30 µm) than in the normal controls, and had a larger coefficient of variation. Significant differences were observed in the mean diameter of the terminal ducts of patients with MGD before and after meibum gland massage (133.73 ± 27.81 μm vs. 102.26 ± 24.30 μm, p < 0.001). Patients with MGD have more diversified orifices and larger meibomian gland terminal duct diameters than normal subjects. In addition, meibomian gland terminal duct diameters seem to decrease in patients with MGD after meibum gland massage.
| S-EPMC7601658 | biostudies-literature
Project description:Studies have estimated that currently 344 million people worldwide and 16.4 million adults in the US have some form of dry eye disease (DED). It is believed that approximately 70% of DED cases are due to some form of evaporative dry eye, for which Meibomian gland dysfunction (MGD) is the major cause. Unfortunately, currently there is no effective treatment for MGD, and solely palliative care is available. Given the importance of MGD in DED, there has been a growing interest in studying Meibomian gland development, homeostasis and pathology, and, also, in developing therapies for treating and/or preventing MGD. For such, animal models have shown to be a vital tool. Much of what is known today about the Meibomian gland and MGD was learnt from these important animal models. In particular, canine and rabbit models have been essential for studying the physiopathology and progression of DED, and the mouse model, which includes different knockout strains, has enabled the identification of specific pathways potentially involved in MGD. Herein, we provide a bibliographic review on the various animal models that have been used to study Meibomian gland development, Meibomian gland homeostasis and MGD, primarily focusing on publications between 2000 and 2020.
| S-EPMC7700490 | biostudies-literature
Project description:Meibomian gland dysfunction (MGD) may be the leading cause of dry eye syndrome throughout the world. However, the precise mechanism(s) underlying the pathogenesis of this disease is unclear. This study was conducted to identify meibomian gland genes that may promote the development and/or progression of human MGD.Lid tissues were obtained from male and female MGD patients and age-matched controls after eyelid surgeries (e.g., to correct entropion or ectropion). Meibomian glands were isolated and processed for RNA extraction and the analysis of gene expression.The results show that MGD is associated with significant alterations in the expression of almost 400 genes in the human meibomian gland. The levels of 197 transcripts, including those encoding various small proline-rich proteins and S100 calcium-binding proteins, are significantly increased, whereas the expression of 194 genes, such as claudin 3 and cell adhesion molecule 1, is significantly decreased. These changes, which cannot be accounted for by sex differences, are accompanied by alterations in many gene ontologies (e.g., keratinization, cell cycle, and DNA repair). The findings also show that the human meibomian gland contains several highly expressed genes that are distinct from those in an adjacent tissue (i.e., conjunctival epithelium).The results demonstrate that MGD is accompanied by multiple changes in gene expression in the meibomian gland. The nature of these alterations, including the upregulation of genes encoding small proline-rich proteins and S100 calcium-binding proteins, suggest that keratinization plays an important role in the pathogenesis of MGD.
| S-EPMC3088560 | biostudies-literature
Project description:TOPIC:To discuss the pathology, causes, and ocular surface impact of meibomian gland disease (MGD), as well as its relationship to dry eye. CLINICAL RELEVANCE:MGD is a common disorder with various contributing mechanisms and clinical manifestations. Understanding MGD pathophysiology and its relationship to dry eye is important in order to optimize diagnosis and treatment algorithms. METHODS:A review of current literature was performed to discern MGD in terms of pathophysiology, risk factors, and ocular surface impact, and the relationship to dry eye. RESULTS:Meibomian gland obstruction and meibocyte depletion are important components of MGD. Many pathologies can disrupt function of meibomian glands, ranging from congenital to acquired causes. Once gland disruption occurs, the quality and quantity of meibum is altered, with a negative impact on the ocular surface. Increased tear evaporation, tear hyperosmolarity, increased ocular surface staining, increased inflammation, symptomatic irritation of the eyelid and globes, as well as decreased visual acuity have all been observed. CONCLUSION:MGD leads to changes in meibum quality and quantity that can cause evaporative dry eye and ocular surface disruption, leading to dry eye symptoms in some individuals.
| S-EPMC5685175 | biostudies-other
Project description:PurposeTo investigate the comparative efficacy of intense pulsed light (IPL) therapy alone with that of IPL plus meibomian gland expression (MGX) for meibomian gland dysfunction (MGD).MethodsThis is a prospective randomized crossover clinical trial. Sixty patients were enrolled and randomly assigned to two groups. All of patients underwent four treatment sessions in total, which were two weeks apart. Group 1 underwent two sessions of IPL therapy with MGX, as well as two sessions of IPL alone. Group 2 received two sessions of IPL therapy alone, and two sessions of IPL therapy with MGX. The following parameters were measured at baseline (BL), 2 weeks after the second treatment session (FU1), and 2 weeks after the fourth treatment session (FU2): tearfilm break-up time (BUT), Oxford grade for corneal staining, meibomian gland expressibility (MGE), meibum quality (MQ), and ocular surface disease index (OSDI). The separate effect of MGX on improvement of MGD parameters was evaluated using generalized estimating equation (GEE).ResultsThe mean age of the participants was 57.52 ± 10.50 years. The BUT, Oxford grade, MGE, MQ, and OSDI of both groups improved significantly (from baseline) by the end of four treatment sessions (FU2 compared to BL; all p-values <0.05). The MGE and MQ significantly improved after the first and second treatment sessions (FU1 compare to BL; all p-values < 0.001). However, the improvement was not statistically significant after the third and fourth treatment sessions (FU2 compared to FU1; p-value of 0.388 for MGE and 0.645 for MQ in group 1, 0.333 for MGE and 0.333 for MQ in group 2). The IPL plus MGX therapy produced greater improvements in the BUT scores than did IPL therapy alone (p = 0.003 by GEE). In contrast, the Oxford grade, MGE, MQ, and OSDI were not influenced by the addition of MGX to IPL (p = 0.642, 0.663, 0.731, and 0.840, respectively by GEE).ConclusionIPL therapy effectively improves the subjective symptoms and objective ocular findings of MGD. MGX enhanced the improvement of BUT driven by IPL therapy. The meibomian gland function (MGE and MQ) recovers faster in response to IPL therapy than did the other parameters.
| S-EPMC7932142 | biostudies-literature
Project description:Instability of the tear film with rapid tear break-up time is a common feature of aqueous-deficient and evaporative dry eye diseases, suggesting that there may be a shared structural abnormality of the tear film that is responsible for the instability. It may be that a change in the normal meibum lipid composition and conformation causes this abnormality. Principle component analyses of infrared spectra of human meibum indicate that human meibum collected from normal donors (Mn) is less ordered than meibum from donors with meibomian gland dysfunction (Md). In this study the conformation of Md was quantified to test this finding.Changes in lipid conformation with temperature were measured by infrared spectroscopy. There were two phases to our study. In phase 1, the phase transitions of human samples, Mn and Md, were measured. In phase 2, the phase transitions of model lipid standards composed of different waxes and cholesterol esters were measured.The phase-transition temperature was significantly higher (4°C) for the Md compared with the Mn of age-matched donors with no history of dry-eye symptoms. Most (82%) of the phase-transition temperatures measured for Md were above the values for Mn. The small change in the transition temperature was amplified in the average lipid order (stiffness) at 33.4°C. The average lipid order at 33.4°C for Md was significantly higher (30%, P = 0.004) than for Mn. The strength of lipid-lipid interactions was 72% higher for Md than for Mn. The ability of one lipid to influence the melting of adjacent lipids is termed cooperativity. There were no significant differences between Mn and Md in phase-transition cooperativity, nor was there a difference between Mn and Md in the minimum order or maximum order that Mn and Md achieved at very low and very high temperatures, respectively. The model wax studies showed that the phase transition of complex mixtures of natural lipids was set by the level of unsaturation. A double bond decreased the phase-transition temperature by approximately 40°C. The addition of a second CH CH moiety decreased the phase-transition temperature by approximately 19°C. Unsaturated waxes were miscible with saturated waxes. When a saturated wax was mixed with an unsaturated one, the saturated wax disproportionately increased the phase transition of the mixture by approximately 30°C compared with the saturated wax alone. Cholesterol ester had little effect on the phase-transition temperature of the waxes. Model studies indicated that changes in the amount of lipid saturation, rather than the amount of cholesterol esters, could be a factor in the observed conformational changes.Meibum lipid compositional changes with meibomian gland dysfunction reflect changes in hydrocarbon chain conformation and lipid-lipid interaction strength. Spectroscopic techniques are useful in studying the lipid-lipid interactions and conformation of lipid from individual patients. (ClinicalTrials.gov number, NCT00803452.).
| S-EPMC3109056 | biostudies-literature
Project description:PurposeTo determine the reliability and clinical relevance of in vivo confocal microscopy (IVCM)-based immune-cellular metrics of palpebral conjunctival inflammation in meibomian gland dysfunction (MGD).MethodsSixteen MGD patients and 13 reference controls included in this cross-sectional, retrospective study, had an ocular surface exam, symptom assessment (Ocular Surface Disease Index questionnaire [OSDI]), and palpebral conjunctival IVCM imaging. Bland-Altman analyses, intraclass correlation coefficient (ICCa), Lin's concordance correlation coefficient (?c), receiver operating characteristic (ROC) analyses, and correlations were performed. Clinical outcome measures were symptom severity (OSDI scores), tear break-up time (TBUT), and corneal fluorescein staining (CFS grade).ResultsCompared to controls, patients with MGD had variable symptom severity (average OSDI score: 48.3 ± 7.6, P = 0.0008, range: 8.3-85.42), shorter TBUT (6.8 ± 0.9 seconds, P = 0.002), comparable corneal staining (0.31 ± 0.19, P = 0.20), and greater conjunctival inflammation (epithelial immune cells [EIC]: 477.8 ± 54.2 vs. 123.3 ± 17.2 cells/mm2, P < 0.0001; intraglandular immune cells [IGIC]: 41.9 ± 3.3% vs. 20.33 ± 7.3%, P < 0.01). Immune-cellular metrics had high inter- and intraobserver agreement (?c: 0.86-0.94; ICCa and Cronbach's ?: 0.85-0.97, P < 0.0001). EIC correlated positively with OSDI (rs: 0.49, P = 0.03), while both EIC and IGIC correlated inversely with TBUT (rs: -0.47, -0.45, P < 0.05), and had high accuracy in detecting inflammation (ROC area under the curve [AUC]: 0.97 and 0.89, P ? 0.001).ConclusionsEIC and IGIC are increased in highly symptomatic patients with MGD that have minimal corneal staining, and correlate with symptoms and clinical signs. EIC and IGIC may provide reliable and clinically relevant metrics of inflammation.
| S-EPMC6314224 | biostudies-literature
Project description:To determine the efficacy duration of eyelid hygiene for meibomian gland dysfunction (MGD) treatment, a total of 1015 participants with primary MGD, followed for at least 6 months, were enrolled. The participants were classified into the eyelid hygiene group and the control group. The participants who had stopped eyelid hygiene at any point in the observation period after the initial 2 months were classified into the withdrawal group. Analysis was conducted with a generalized linear mixed model. Treatment group, age, sex, ocular surface inflammation, anti-inflammatory treatments, and baseline MGD subtype were considered as fixed effects, and the individual factor was considered as a random effect. The MGD stage decreased significantly for the observational period in the eyelid hygiene group (p < 0.001). Approximately 40.1% of the participants continuously maintained eyelid hygiene throughout the observational period. The MGD stage in the eyelid hygiene group continued to decrease for 6 months and was maintained thereafter. After 4 months of stopping eyelid hygiene, the MGD stage in the withdrawal group was worse than in the eyelid hygiene group (p < 0.001) and similar to that in the control group (p = 0.762). Maintaining eyelid hygiene was significantly effective in MGD treatment. Efficacy increased with treatment for 6 months, and the efficacy duration was maintained for 4 months even after stopping eyelid hygiene. Therefore, we recommend that patients with MGD maintain eyelid hygiene, and compliance should be checked continuously.
| S-EPMC8837031 | biostudies-literature
Project description:PurposeOcular surface microbiome changes can affect meibomian gland dysfunction (MGD) development. This study aimed to delineate differences among the microbiome of eyelid skin, conjunctiva, and meibum in healthy controls (HCs) and patients afflicted with MGD.MethodsShotgun metagenomic analysis was used to determine if there are differences between the microbial communities in ocular sites surrounding the meibomian gland in healthy individuals and patients afflicted with MGD.ResultsThe meibum bacterial content of these microbiomes was dissimilar in these two different types of individuals. Almost all of the most significant taxonomic changes in the meibum microbiome of individuals with MGD were also present in their eyelid skin, but not in the conjunctiva. Such site-specific microbe pattern changes accompany increases in the gene expression levels controlling carbohydrate and lipid metabolism. Most of the microbiomes in patients with MGD possess a microbe population capable of metabolizing benzoate. Pathogens known to underlie ocular infection were evident in these individuals. MGD meibum contained an abundance of Campylobacter coli, Campylobacter jejuni, and Enterococcus faecium pathogens, which were almost absent from HCs. Functional annotation indicated that in the microbiomes of MGD meibum their capability to undergo chemotaxis, display immune evasive virulence, and mediate type IV secretion was different than that in the microbiomes of meibum isolated from HCs.ConclusionsMGD meibum contains distinct microbiota whose immune evasive virulence is much stronger than that in the HCs. Profiling differences between the meibum microbiome makeup in HCs and patients with MGD characterizes changes of microbial communities associated with the disease status.
| S-EPMC7425691 | biostudies-literature