The influence of 13-cis retinoic acid on human meibomian gland epithelial cells

Evaluation of the Safety and Tolerability of Lumify Eye Illuminations Cosmetic Products

Purpose

Cosmetic products applied to the periocular area can cause skin sensitivity reactions, and manufacturers routinely test the safety and tolerability of products in development. This research was sponsored by Bausch + Lomb to evaluate three Lumify Eye Illuminations products: a lash and brow serum, a hydra-gel eye cream, and a micellar water eye makeup remover.

Methods

A cumulative irritation test (CIT) study and a repeated insult patch test (RIPT) study enrolled adult males or females with no known sensitivities to cosmetic products. Three clinical safety studies enrolled adult females with self-reported characteristics targeted by each product, which was applied in a manner consistent with expected use for 8 or 12 weeks.

Results

In CIT (n=34) and RIPT (n=201) studies, faint/minimal erythema reactions were observed in 0% to 2.9% of participants; there were no moderate or severe reactions. No safety signals were observed in participants who completed clinical safety studies for lash and brow serum (n=66 enrolled, n=55 completed [83%]), eye cream (n=61 enrolled, n=52 completed [85%]), or eye makeup remover (n=80 enrolled, n=68 completed [85%]). No clinically relevant changes in visual acuity or ophthalmologic slit-lamp examination findings were noted. No participants reported ocular sensations of burning/stinging, foreign-body sensation, or soreness. At the final clinical safety study assessment, mild cutaneous erythema (as graded by the investigator) was reported for one participant (eye cream study); no other prespecified signs of cutaneous irritation (eg, edema, dryness) were observed. A treatment-related adverse event that led to study discontinuation was experienced by one participant in the eye makeup remover study (bilateral periorbital swelling).

Conclusion

Findings from rigorously conducted irritation testing and clinical safety studies indicated that these products were safe and well tolerated. Increased availability of data regarding ocular and cutaneous safety of cosmetic products can inform consumer decision-making and eye care provider recommendations.

13-cis Retinoic Acid-Mediated Modulation of Human Meibomian Gland Epithelial Cells Development: Implications for In Vitro Modeling of Meibomian Gland Dysfunction

Purpose: This study aimed to investigate the effect of 13-cis retinoic acid (13-cis RA) on human meibomian gland epithelial cells (HMGECs) and explore the potential of using this experimental model as an in vitro approach for studying meibomian gland dysfunction (MGD). Methods: First, HMGECs were cultured with 13-cis RA at different doses and times, and cell viability and proliferation rates were assessed to determine the appropriate stimulation concentration and time. Subsequently, during the proliferation stage, the expression of proliferation, inflammation, and oxidative stress genes and their products were evaluated. The meibum synthesis capacity was determined during the differentiation stage. Additionally, the peroxisome proliferator-activated receptor gamma (PPARγ) antagonist GW9662 was used as a control to assess the impact of 13-cis RA on PPARγ. Results: 13-cis RA significantly inhibited cell viability and proliferation in a time-dose response manner. Under the stimulation of 2 and 5 μM for 48 h during the proliferation stage, a significant decrease was observed in the expression of cell proliferation markers Ki67, antioxidant SOD-2, and Nrf-2. However, the expression of the pro-inflammatory factors IL-1β, IL-8, MMP9, and oxidative stress markers NOX-4 and reactive oxygen species increased. During the differentiation stage, it suppressed meibum synthesis and the expression of meibocyte differentiation-related proteins adipose differentiation-associated protein 4 (ADFP4), elongation of very long chain fatty acid protein 4 (ELOVL4), sterol regulatory element-binding protein 2 (SREBP-2), and PPARγ. Conclusion: 13-cis RA inhibited cell viability, promoted inflammation and oxidative stress, and suppressed meibum synthesis through the PPARγ pathway. Our study shed light on the effect of 13-cis RA on HMGECs and provided a promising direction for studying MGD in vitro.

Epidemiology and Risk Factors of Dry Eye Disease: Considerations for Clinical Management

Dry eye disease is a multifactorial condition characterised by tear film instability, hyperosmolarity and ocular surface inflammation. Understanding the epidemiology of dry eye disease and recognising both modifiable and non-modifiable risk factors can assist eye care practitioners in assessing, treating, and managing patients with the condition. This review considers current knowledge surrounding its incidence and prevalence, as well as associated demographic, systemic, ocular, and iatrogenic, and lifestyle-related modifiable risk factors. Population-based prevalence estimates vary according to the diagnostic criteria used to define dry eye disease, as well as severity and demographic characteristics of the population. Considering recent data and variable population demographics, conservative prevalence estimates suggest that 10-20% of the population over 40 years of age report moderate to severe symptoms and/or seek treatment for dry eye disease. Individuals with specific non-modifiable demographic risk factors may be at increased risk of developing dry eye disease. Advanced age, female sex and East Asian ethnicity have been identified as key non-modifiable demographic features predisposing individuals to dry eye disease. Systemic conditions that have been associated with an increased risk of dry eye disease include migraine, Sjögren syndrome, connective tissue disorders, mental health disorders, diabetes mellitus and androgen deficiency. Medications that may contribute to this risk include antidepressants, antihistamines, and hormone replacement therapy. Ocular and iatrogenic risk factors of dry eye disease include blepharitis, Demodex infestation, ocular surgery, blink completeness, contact lens wear, and topical ophthalmic medications. A range of modifiable lifestyle factors that can increase the risk of dry eye disease have also been identified, including low humidity environments, digital screen use, quality of sleep, diet, and eye cosmetic wear. Dry eye is a common disease affecting millions globally. Increasing knowledge regarding its associated risk factors can better prepare the eye care practitioner to successfully manage patients with this ocular surface disease.

Using machine learning model explanations to identify proteins related to severity of meibomian gland dysfunction

Meibomian gland dysfunction is the most common cause of dry eye disease and leads to significantly reduced quality of life and social burdens. Because meibomian gland dysfunction results in impaired function of the tear film lipid layer, studying the expression of tear proteins might increase the understanding of the etiology of the condition. Machine learning is able to detect patterns in complex data. This study applied machine learning to classify levels of meibomian gland dysfunction from tear proteins. The aim was to investigate proteomic changes between groups with different severity levels of meibomian gland dysfunction, as opposed to only separating patients with and without this condition. An established feature importance method was used to identify the most important proteins for the resulting models. Moreover, a new method that can take the uncertainty of the models into account when creating explanations was proposed. By examining the identified proteins, potential biomarkers for meibomian gland dysfunction were discovered. The overall findings are largely confirmatory, indicating that the presented machine learning approaches are promising for detecting clinically relevant proteins. While this study provides valuable insights into proteomic changes associated with varying severity levels of meibomian gland dysfunction, it should be noted that it was conducted without a healthy control group. Future research could benefit from including such a comparison to further validate and extend the findings presented here.

Evaluation of recovery time of tear film function and ocular surface after discontinuing oral isotretinoin treatment for acne vulgaris : Correlation between oral isotretinoin and tear film function

PURPOSE

This study aimed to evaluate the recovery time of tear film function and ocular surface after discontinuing systemic isotretinoin treatment.

METHODS

This was a prospective, cross-sectional study. 34 eyes of 17 patients treated with low- dose oral isotretinoin (< 0.5 mg/kg/day) were enrolled. The modified OSDI score, tear break-up time, Schirmer test, and corneal staining were performed in all patients at baseline, during the course of treatment and after withdrawing treatment every two weeks until the result returned to baseline.

RESULTS

Tear breakup time appeared to be the most sensitive and changed significantly at 2 weeks after starting treatment (p < 0.001) and returned to baseline at 4 weeks after withdrawal from treatment (p < 0.001). The Schirmer test results significantly decreased at 6 weeks and returned to baseline at 4 weeks after withdrawal from treatment (p < 0.001). OSDI scores were significantly changed at 6 weeks after treatment (81.8%) and returned to baseline at 2 weeks (54.5%) after withdrawal from treatment. No significant change was found in the MGD. Corneal staining was significantly positive 90.9% 6 weeks after starting treatment and returned to baseline 6 weeks after withdrawal from treatment (p < 0.001).

CONCLUSION

Dry eye disease can return to baseline levels after treatment withdrawal. At least 6 weeks later, they could wear contact lenses again, and it was useful to prepare all patients requiring further ocular surgery.

Retinol palmitate in management of chronic Steven-Johnson Syndrome with ocular surface keratinization

PURPOSE

To study the outcomes of topical Retinol Palmitate ophthalmic solution in chronic Stevens-Johnson Syndrome with ocular surface keratinisation.

METHODS

It was a comparative interventional study conducted at Rajendra Prasad Centre for Ophthalmic Sciences, Delhi, India from 2020 to 2022 evaluating outcomes of addition of topical Retinol Palmitate to conventional treatment objectively as well as subjectively from baseline up to 12 weeks.

RESULTS

A statistically significant improvement was seen in patients who received topical Retinol palmitate at 12 weeks in terms of Schirmer-1 test(p=<0.01), tear prism height on ASOCT(p = 0.02), Rose Bengal staining score of cornea(p = 0.01) and conjunctiva (p < 0.01), reduction of ocular surface keratinisation on impression cytology(p = 0.01) and subjective evaluation using OSDI questionnaire(p = 0.04).Impression cytology revealed goblet cells in Retinol palmitate group at 1 week after initiation of therapy, which increased further at 1 month follow up but reduced at 3 months. No goblet cells were seen in control group at any follow-up. No significant difference was noted between the two groups in terms of visual acuity, tear film breakup time, inflammatory cells on impression cytology and inflammatory markers in tears.

CONCLUSION

Topical Retinol palmitate is a safe and effective drug in cases of chronic SJS with ocular surface keratinisation. It has the potential to reverse keratinisation of the ocular surface and promote development of goblet cells. However, the survival of goblet cells is not long lasting.

The Effect of Oral Isotretinoin Therapy on Meibomian Gland Characteristics in Patients with Acne Vulgaris

INTRODUCTION

The aim of the study was to determine the effect of oral isotretinoin therapy on the functional and morphological condition of the anterior segment of the eye, with particular emphasis on the meibomian glands.

METHODS

Twenty-four patients (48 eyes) with a diagnosis of acne vulgaris were involved in the survey. All patients underwent a thorough ophthalmological examination at three time points: before therapy, 3 months after the start of therapy, and 1 month after the completion of isotretinoin therapy. The physical examination included the following elements: blink rate, analysis of the lid margin abnormality score (LAS), tear film break-up time (TFBUT) and Schirmer's test, meibomian gland loss (MGL), and the evaluation of the meibum quality score (MQS) and meibum expressibility score (MES). Additionally, the total score of an ocular surface disease index (OSDI) questionnaire was analysed.

RESULTS

In comparison with pretreatment values, significant increases in OSDI during and after the treatment (p = 0.003 and p = 0.004, respectively) were observed. Substantial deterioration during the treatment was observed for MGL (p < 0.0001), MQS (p < 0.001) and LAS (p < 0.0001), while an improvement in those parameters after isotretinoin cessation was observed (p = 0.006, p = 0.02 and p = 0.0003, respectively). The frequency of using artificial eye drops was positively associated with MGL during (Spearman's rank correlation coefficient (Rs) =  + 0.31; p = 0.03) and after the cessation of the therapy (Rs =  + 0.28; p = 0.04). Meibomian gland atrophy correlated significantly with MQS during (Rs =  + 0.29; p = 0.04) and after treatment (Rs =  + 0.38; p = 0.008). The decrease in TFBUT values correlated with increased LAS (Rs = - 0.31; p = 0.03) during the course of isotretinoin usage. We found no changes in Schirmer's test or blink rates.

CONCLUSION

Isotretinoin therapy leads to increased ocular complaints related to lipid tear film component dysfunction. This is due to reversible changes in meibomian gland morphology and function observed during drug usage.

Impact of Exposomes on Ocular Surface Diseases

Ocular surface diseases (OSDs) are significant causes of ocular morbidity, and are often associated with chronic inflammation, redness, irritation, discomfort, and pain. In severe OSDs, loss of vision can result from ocular surface failure, characterised by limbal stem cell deficiencies, corneal vascularisation, corneal opacification, and surface keratinisation. External and internal exposomes are measures of environmental factors that individuals are exposed to, and have been increasingly studied for their impact on ocular surface diseases. External exposomes consist of external environmental factors such as dust, pollution, and stress; internal exposomes consist of the surface microbiome, gut microflora, and oxidative stress. Concerning internal exposomes, alterations in the commensal ocular surface microbiome of patients with OSDs are increasingly reported due to advancements in metagenomics using next-generation sequencing. Changes in the microbiome may be a consequence of the underlying disease processes or may have a role in the pathogenesis of OSDs. Understanding the changes in the ocular surface microbiome and the impact of various other exposomes may also help to establish the causative factors underlying ocular surface inflammation and scarring, the hallmarks of OSDs. This review provides a summary of the current evidence on exposomes in various OSDs.

Meibomian gland development: Where, when and how?

The Meibomian gland (MG) is an indispensable adnexal structure of eye that produces meibum, an important defensive component for maintaining ocular homeostasis. Normal development and maintenance of the MGs is required for ocular health since atrophic MGs and disturbances in composition and/or secretion of meibum result in major ocular pathologies, collectively termed as Meibomian gland dysfunction (MGD). Currently available therapies for MGD merely provide symptomatic relief and do not treat the underlying deficiency of the MGs. Hence, a thorough understanding of the timeline of MG development, maturation and aging is required for regenerative purposes along with signaling molecules & pathways controlling proper differentiation of MG lineage in mammalian eye. Understanding the factors that contribute to the development of MGs, developmental abnormalities of MGs, and changes in the quality & quantity of meibum with developing phases of MGs are essential for developing potential treatments for MGD. In this review, we compiled a timeline of events and the factors involved in the structural and functional development of MGs and the associated developmental defects of MGs during development, maturation and aging.

TFOS Lifestyle: Impact of elective medications and procedures on the ocular surface

The word "elective" refers to medications and procedures undertaken by choice or with a lower grade of prioritization. Patients usually use elective medications or undergo elective procedures to treat pathologic conditions or for cosmetic enhancement, impacting their lifestyle positively and, thus, improving their quality of life. However, those interventions can affect the homeostasis of the tear film and ocular surface. Consequently, they generate signs and symptoms that could impair the patient's quality of life. This report describes the impact of elective topical and systemic medications and procedures on the ocular surface and the underlying mechanisms. Moreover, elective procedures performed for ocular diseases, cosmetic enhancement, and non-ophthalmic interventions, such as radiotherapy and bariatric surgery, are discussed. The report also evaluates significant anatomical and biological consequences of non-urgent interventions to the ocular surface, such as neuropathic and neurotrophic keratopathies. Besides that, it provides an overview of the prophylaxis and management of pathological conditions resulting from the studied interventions and suggests areas for future research. The report also contains a systematic review investigating the quality of life among people who have undergone small incision lenticule extraction (SMILE). Overall, SMILE refractive surgery seems to cause more vision disturbances than LASIK in the first month post-surgery, but less dry eye symptoms in long-term follow up.

TFOS Lifestyle: Impact of cosmetics on the ocular surface

In this report the use of eye cosmetic products and procedures and how this represents a lifestyle challenge that may exacerbate or promote the development of ocular surface and adnexal disease is discussed. Multiple aspects of eye cosmetics are addressed, including their history and market value, psychological and social impacts, possible problems associated with cosmetic ingredients, products, and procedures, and regulations for eye cosmetic use. In addition, a systematic review that critically appraises randomized controlled trial evidence concerning the ocular effects of eyelash growth products is included. The findings of this systematic review highlight the evidence gaps and indicate future directions for research to focus on ocular surface outcomes associated with eyelash growth products.

The inhibition of p38 MAPK blocked inflammation to restore the functions of rat meibomian gland epithelial cells

Meibomian glands (MGs) are vital for ocular surface health. However, the roles of inflammation in the progression of meibomian gland dysfunction (MGD) are largely unknown. In this study, the roles of the inflammation factor interleukin-1β (IL-1β) via the p38 mitogen-activated protein kinases (MAPK) signaling pathway on rat meibomian gland epithelial cells (RMGECs) were explored. Eyelids from adult rat mice at 2 months and 2 years of age were stained with specific antibodies against IL-1β to identify inflammation levels. RMGECs were exposed to IL-1β and/or SB203580, a specific inhibitor of p38 MAPK signaling pathway, for 3 days. Cell proliferation, keratinization, lipid accumulation, and matrix metalloproteinases 9 (MMP9) expression were evaluated by MTT assay, polymerase chain reaction (PCR), immunofluorescence staining, apoptosis assay, lipid staining, and Western blot analyses. We found that IL-1β was significantly higher in the terminal ducts of MGs in rats with age-related MGD than in young rats. IL-1β inhibited cell proliferation, suppressed lipid accumulation and peroxisome proliferator activator receptor γ (PPARγ) expression, and promoted apoptosis while activating the p38 MAPK signaling pathway. Cytokeratin 1 (CK1), a marker for complete keratinization, and MMP9 in RMGECs were also up-regulated by IL-1β. SB203580 effectively diminished the effects of IL-1β on differentiation, keratinization, and MMP9 expression by blocking IL-1β-induced p38 MAPK activation, although it also inhibited cell proliferation. The inhibition of the p38 MAPK signaling pathway blocked IL-1β-induced differentiation reduction, hyperkeratinization, and MMP9 overexpression of RMGECs, which provides a potential therapy for MGD.

A comparative review of evaporative dry eye disease and meibomian gland dysfunction in dogs and humans

Dry eye disease is a complex ophthalmic disorder that consists of two main subtypes, aqueous deficient dry eye (ADDE) and evaporative dry eye disease (EDED). Due to the complex underlying physiology, human dry eye disease can be difficult to model in laboratory animal species. Thus, the identification and characterization of a spontaneous large animal model of dry eye disease is desirable. Dogs have been described as an ideal spontaneous model of ADDE due to the similar pathophysiology between dogs and humans. Recently, EDED and meibomian gland dysfunction (MGD) have been increasingly recognized and reported in dogs. These reports on EDED and MGD in dogs have identified similarities in pathophysiology, clinical presentations, and diagnostic parameters to humans with the comparable disorders. Additionally, the tests that are used to diagnose EDED and MGD in humans are more easily applicable to dogs than to laboratory species due to the comparable globe sizes between dogs and humans. The reported response of dogs to EDED and MGD therapies are similar to humans, suggesting that they would be a valuable preclinical model for the development of additional therapeutics. Further research and clinical awareness of EDED and MGD in dogs would increase their ability to be utilized as a preclinical model, improving the positive predictive value of therapeutics for EDED and MGD in both humans and dogs.

Using Network Pharmacology and Molecular Docking to Explore the Mechanism of Qiju Dihuang Pill against Dry Eye Disease

Background

Dry eye disease (DED) is a multifactorial disease of the ocular surface, which affects the quality of life and work efficiency of affected patients. The traditional Chinese medicine formula Qiju Dihuang Pill (QJDHP) has a good therapeutic effect on DED. However, the pharmacological mechanism is not clear.

Objective

To explore the mechanism of QJDHP in the treatment of DED based on network pharmacology.

Method

The active components in QJDHP were screened in Traditional Chinese Medicine Systems Pharmacology (TCMSP), and putative molecular targets of QJDHP were identified using the SwissTargetPrediction database. DED-related targets were screened by GeneCards and OMIM. We established protein-protein interaction (PPI) and core targets and corresponding active compound network by Cytoscape to identify the core targets and main compounds of QJDHP against DED. DAVID database was utilized for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Molecular docking was used to evaluate the binding activity between key active compounds and core targets.

Results

The results of network pharmacology showed that 253 targets of QJDHP were related to DED. PPI network analysis showed the 18 core targets. The binding affinity of docking results ranged from -5.7 to -9.3 kcal/mol, indicating a good docking effect. The results of GO enrichment analysis showed that the mechanism of QJDHP in the treatment of DED mainly involved biological processes such as apoptosis, oxidative stress, response to estrogen, angiogenesis, and the regulation of transcription factors. KEGG analysis showed that QJDHP may be regulated by the TNF signaling pathway, Toll-like receptor signaling pathway, MAPK signaling pathway, and estrogen signaling pathway in the treatment of DED.

Conclusion

In this study, we demonstrated the multicomponent, multitarget, and multichannel action mechanism of QJDHP in the treatment of DED and provided a foundation for further drug development research.

Effects of PPAR-γ and RXR-α on mouse meibomian gland epithelial cells during inflammation induced by latanoprost

The purpose of this study is to investigate the effects of latanoprost on the secretion of cytokines and chemokines from meibomian gland epithelial cells, and to evaluate the modulation of peroxisome proliferator-activated receptor γ (PPAR-γ) and retinoid X receptor α (RXR-α) during latanoprost-induced inflammation. Mouse meibomian gland epithelial cells were cultured in proliferation and differentiation medium, respectively. Cells were exposed to latanoprost, rosiglitazone (PPAR-γ agonist), or LG100268 (RXR-α agonist), respectively. The expression of IL-6, IL-1β, TNF-α, MMP-9, MCP-1, and CCL-5 were detected by real-time PCR and ELISA. The effect of latanoprost, rosiglitazone, LG100268, and inflammatory cytokines on the differentiation of meibocyte were evaluated by related gene expression and lipid staining. The expression of Keratin-1, 6, 17 protein was detected by western immunoblotting. The results showed that the above cytokines could be induced by latanoprost in meibomian gland epithelial cells. LG100268 and rosiglitazone could inhibit the production of IL-6 and TNF-α induced by latanoprost, respectively. Latanoprost suppressed the expression of differentiation-related mRNA through a positive feedback loop by enhancement of COX-2 expression via FP receptor-activated ERK signaling. The expression of Keratin-17 was upregulated by rosiglitazone and suppressed by LG100268. The application of IL-6 and TNF-α showed negative effects on lipid accumulation in meibomian gland epithelial cells. These results demonstrated that latanoprost could induce inflammation and suppress differentiation of mouse meibomian gland epithelial cells. The activation of PPAR-γ and RXR-α showed an anti-inflammatory effect, showing a potential role to antagonize the effect of latanoprost eyedrops on meibomian gland epithelial cells.

The effects of the systemic isotretinoin treatment on ocular surface and meibomian glands: a prospective longitudinal study

PURPOSE

To assess the effects of systemic isotretinoin therapy (SIT) on the ocular surface, meibomian glands (MG) and cornea microstructure in acne vulgaris (AV) patients.

METHODS

Patients with AV (n = 20) and healthy controls (n = 20) were enrolled in the study. All participants underwent ocular surface tests in the order of ocular surface disease index (OSDI) questionnaire, corneal sensitivity, tear break-up time (BUT), fluorescein and lissamine green (LG) staining and Schirmer II test with anaesthesia. MG alterations were evaluated with meibography for upper (UE) and lower eyelids (LE) separately. Corneal basal epithelium and subbasal nerve plexus (SNP) were evaluated using In Vivo Confocal Microscopy (IVCM).

RESULTS

Schirmer II test with anaesthesia, BUT, corneal sensitivity, fluorescein and LG staining grades and OSDI score results showed no difference between the control group and the baseline of the patient group. Whereas the meibomian gland dysfunction (MGD) grades, UE and LE meiboscores were higher in the patient group at the baseline (p = 0.013, p = 0.004, p = 0.008 respectively). The Control group possessed higher numbers of total and long nerve fibres compared with patients at the baseline (p ≤ 0.001 for both two values). Compared to the baseline and the third month, BUT decreased and fluorescein staining grades increased (p = 0.017 and p = 0.043, respectively). MGD grades, UE and LE meiboscores increased in the third month compared to the baseline (p < 0.001, p < 0.001, p = 0.008 respectively). Basal epithelial cell density (BECD) decreased in the third month of SIT (p = 0.043).

CONCLUSIONS

This prospective study showed that systemic Isotretinoin treatment effects not only ocular surface parameters but also corneal and Meibomian glands structure. Considering early alterations in the course of treatment, ophthalmological assessment and follow-up during SIT are mandatory.

Isotretinoin Impairs the Secretory Function of Meibomian Gland Via the PPARγ Signaling Pathway

Purpose

To investigate the effects of isotretinoin on the ocular surface and to explore the possible mechanisms.

Methods

Rats were treated with isotretinoin 20 mg/kg/d for five months and tested monthly for tear secretion, fluorescein staining, and infrared photography. After five months of treatment, tissues were harvested for routine staining to evaluate the morphological changes; and real-time polymerase chain reaction, Western blot, and immunohistochemistry to study the expression of associated genes and their products such as forkhead box protein O1 (FoxO1), forkhead box protein O3, peroxisome proliferator–activated receptor γ (PPARγ), adipose differentiation–related protein, elongation of very long chain fatty acids protein 4, fatty acid binding protein 4, matrix metalloproteinase-9, and interleukin-6.

Results

Systemically, isotretinoin-treated rats have a significantly lower body weight that controls and apparent skin damage. Locally, although there was no alteration in tear secretion, a significant corneal involvement indicated by increased fluorescein staining scores, and also the contrast of meibomian gland was significantly reduced but no significant atrophy of the acinus was found. In addition, isotretinoin causes a decrease in conjunctival goblet cells. Furthermore, isotretinoin treatment did not cause the upregulation of FoxO1 and inflammation related genes but significantly suppressed the expression of PPARγ pathway.

Conclusions

Isotretinoin does not cause a significant atrophy of the acinus and a significant change of FoxO1 expression in the meibomian gland. Isotretinoin causes meibomian gland dysfunction, affecting meibocyte differentiation and qualitative and quantitative changes in the meibum, through PPARγ pathway.

The effect of isotretinoin on meibomian glands in eyes: a pilot study

PURPOSE

The aim of this pilot study was to quantify the meibography changes in patients administered with oral isotretinoin.

METHODS

This prospective pilot study included 30 eyes of 30 patients who received oral isotretinoin treatment due to acne. Each patient underwent a general ophthalmological examination. After fluorescence staining of the ocular surface, the tear film break-up time (TFBUT) test, meibography and Schirmer test were carried out and noted. All of these procedures were applied before the treatment and repeated at 1, 3, and 6 months after the treatment.

RESULTS

The percentage of upper meibomian gland (MG) loss at 3 and 6 months after the treatment was 22.2% (p = 0.001) and 23.6% (p = 0.001), respectively. The percentage of lower MG loss at 3 and 6 months after the treatment was 18.7% (p = 0.001) and 20.7% (p = 0.001), respectively. The corneal fluorescein staining score at 3 and 6 months after treatment was 0.57 (p = 0.001), and 0.47 (p = 0.012), respectively.

CONCLUSION

These findings show that oral isotretionin treatment may affect MG morphology. The study findings also suggest that isotretinoin may cause tear film instability with Meibomian gland dysfunction and may cause evaporative type of dryness.

Expression of Acyl-CoA wax-alcohol acyltransferase 2 (AWAT2) by human and rabbit meibomian glands and meibocytes

PURPOSE

Previously, we showed that Acyl-CoA wax-alcohol acyltransferase 2 (AWAT2), an essential enzyme required for meibum wax ester synthesis, was not expressed by immortalized human meibomian gland epithelial cells (hMGEC) in culture. To begin to understand the mechanisms controlling AWAT2 expression, we have analyzed its expression in human and rabbit meibomian glands and cultured meibocytes.

METHODS

Rabbit meibocyte progenitor cells (rMPC) were first grown in Cnt-BM.1 basal medium (Cellntec) supplemented with rhEGF, FGF10, and ROCK inhibitor (Y-27632 dihydrochloride), and then passed at 70-80% confluency with Accutase. Differentiation of rMPC to meibocytes (rMC) was induced by removal of Y-27632 and addition of 1 mM calcium with and without PPARγ agonists. RNA from the tissue, primary, passaged rMPC and differentiated rMC were obtained for AWAT2 qPCR analysis. Proteins and cells were evaluated for western blotting and neutral lipid synthesis, respectively. For comparison, human meibomian glands were separated for RNA and protein analysis. hMGEC was cultured to collect RNA and protein.

RESULTS

Rabbit rMPCs were successfully grown, passaged, and differentiated, showing a significant increase in lipid droplet accumulation. AWAT2 RNA was highly expressed in tissue but showed a -16.9 log2 fold decrease in primary and passaged rMPCs and was not induced by differentiation to rMC. By comparison, human meibomian glands showed high expression of AWAT2, and hMGEC expressed non-detectable levels of AWAT2 transcripts or protein.

CONCLUSIONS

AWAT2 expression is lost in cultured rMPC and rMC suggesting that cells in culture do not undergo complete meibocyte differentiation and require yet to be identified culture conditions.

Hyperkeratinization and Proinflammatory Cytokine Expression in Meibomian Glands Induced by Staphylococcus aureus

Purpose

This exploratory study aimed to investigate the morphological and pathological alterations of the meibomian gland (MG) with the Staphylococcus aureus crude extracts (SACEs) treatment.

Methods

Mouse MG explants were cultured and differentiated with or without SACEs for 48 hours. Explant's viability and cell death were determined by thiazolyl blue tetrazolium bromide (MTT) assay and TUNEL assay. MG morphology was observed by Hematoxylin and Eosin staining. Lipid droplet production was detected by Nile Red staining and LipidTox immunostaining. The pro-inflammatory cytokines were detected by ELISA. The relative gene and protein expression in MG explants was determined via quantitative RT-PCR, immunostaining, and immunoblotting. The components of the SACEs were analyzed by immunoblotting and silver staining.

Results

Our findings demonstrated that the SACEs treatment induced overexpression of keratin 1 (Krt1) in the ducts and acini of MG explants, accompanied by a decrease in viability and an increase in cell death in explants. Furthermore, the SACEs treatment dose-dependently increased the levels of TNF-α, IL-1β, and IL-6 in MG explants. The SACEs treatment induced activation of the nuclear factor kappa B (NF-κB) and AIM2 (absent in melanoma 2)/ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain) inflammasome signaling pathway in explants. Further investigation showed expression of the key adipogenesis-related molecule peroxisome proliferator-activated receptor γ was decreased after SACEs treatment. However, no change was found in the lipid synthesis of MG explants after treatment with the SACEs. Staphylococcal enterotoxins B (SEB) was detected in the SACEs. SEB induced the overexpression of Krt1 and IL-1β in ducts and acini of MG explants.

Conclusions

Our findings confirm that Staphylococcus aureus induced hyperkeratinization and pro-inflammatory cytokines expression in MG explants ducts and acini. These effects might be mediated by SEB. Activation of the NF-κB and AIM2/ASC signaling pathway is involved in this process.

Assessing public awareness of daily eyelid hygiene habits in Saudi Arabia: An online survey study

PURPOSE

Incidences of ocular conditions, including meibomian gland dysfunction (MGD), blepharitis, and dry eye have been increasing globally. Eyelid hygiene is key to maintaining ocular surface health and improving ocular symptoms. This study investigated the awareness of eyelid hygiene among the Saudi population.

METHODS

This cross-sectional survey was conducted between April 2020 and May 2020 across all regions of Saudi Arabia through the distribution of an electronic self-administered questionnaire among the Saudi population.

RESULTS

A total of 1102 responses were received (women, 76.3%; men, 23.7%). Only 33.2% respondents reported consciously washing their eyelids, while 70.1% had never heard about MGD; however, most of the respondents (93.2%) had heard about dry eye. Based on the questionnaire results, the Saudi population had suboptimal (18.4%) level of awareness of eyelid hygiene. At least one ocular symptom was reported by 98.1% of the respondents.

CONCLUSION

The level of awareness of eyelid hygiene in Saudi Arabia was found to be suboptimal, particularly among patients with MGD and dry eyes. Poor knowledge about the benefits of daily eyelid hygiene was the primary barrier to its practice. We recommend that ophthalmologists raise awareness of good eyelid hygiene among patients with MGD and eye dryness. Despite the current findings, further studies and evidence are required before recommending daily eyelid hygiene practices in the general population, including those without clinical symptoms of MGD or eye dryness.

Immune signaling in rosacea

Rosacea is a common chronic skin disease affecting mostly people aged 40 and above, with currently no cure. When it affects the eyelids and periocular skin, it leads to dry eye and potentially corneal damage. Research performed over the last decade shed light into the potential mechanisms leading to skin hypersensitivity and provided promising avenues for development of novel, rational therapeutics aimed at reducing the skin inflammatory state. In this review, we discuss the current knowledge on the mechanisms of rosacea in general and of periocular skin-affecting disease in particular, identify key questions that remain to be answered in future research, and offer a disease model that can explain the key characteristics of this disease, with particular emphasis on a potential positive feedback loop that could explain both the acute and chronic features of rosacea.

High-Fat Diet Induces Inflammation of Meibomian Gland

Purpose

To determine if a high-fat diet (HFD) induces meibomian gland (MG) inflammation in mice.

Methods

Male C57BL/6J mice were fed a standard diet (SD), HFD, or HFD supplemented with the peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist rosiglitazone for various durations. Body weight, blood lipid levels, and eyelid changes were monitored at regular intervals. MG sections were subjected to hematoxylin and eosin staining, LipidTox staining, TUNEL assay, and immunostaining. Quantitative RT-PCR and western blot analyses were performed to detect relative gene expression and signaling pathway activation in MGs.

Results

MG acinus accumulated more lipids in the mice fed the HFD. Periglandular CD45-positive and F4/80-positive cell infiltration were more evident in the HFD mice, and they were accompanied by upregulation of inflammation-related cytokines. PPAR-γ downregulation accompanied activation of the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signaling pathways in the HFD mice. There was increased acini cell apoptosis and mitochondria damage in mice fed the HFD. MG inflammation was ameliorated following a shift to the standard diet and rosiglitazone treatment in the mice fed the HFD.

Conclusions

HFD-induced declines in PPAR-γ expression and MAPK and NF-κB signaling pathway activation resulted in MG inflammation and dysfunction in mice.

Remodeling of Cornea With Isotretinoin Treatment

OBJECTIVES

To evaluate the change of corneal epithelial thickness (ET) in subjects using isotretinoin with spectral-domain optical coherence tomography and further to explore reflection of changes on corneal topography.

METHODS

Forty eyes of 40 subjects with acne vulgaris scheduled for oral isotretinoin were included in this prospective study. Subjects were examined with RTVue-XR and Pentacam at baseline, 1th, 3rd, and 6th months of treatment, and 3rd month of isotretinoin cessation.

RESULTS

A statistically significant increase was detected in each sector of ET map except inferonasal 7 to 9 mm between baseline and following visits (P<0.05, for all visits). The increase in superior (2-7 mm), inferior (2-7 mm), and maximum values in epithelium statistics and the decrease in superior (2-7 mm), inferior (2-7 mm), minimum, and maximum values in stroma statistics at follow-up visits were significant (P<0.05, for all visits). Central corneal thickness, maximum Ambrosio-relational thickness, average pachymetric-progression index at 1th, 3rd, and 6th months, and thinnest pachymetry, index of surface variance (ISV) at 3rd, and 6th months differed significantly (P<0.05, for specified visits). The regression in parameters was observed at 3rd month of isotretinoin cessation.

CONCLUSIONS

Isotretinoin treatment induces epithelial thickening and stromal thinning. Remodeling of corneal layers causes statistical differences in ISV and pachymetry-related parameters of Pentacam. The pachymetry changes in cornea return to baseline at the 3rd month of discontinuation of treatment.

Longitudinal assessment of meibomian glands and tear film layer in systemic isotretinoin treatment

PURPOSE

This study aimed to analyze the changes in meibomian glands (MGs) and tear film layer over time in patients taking systemic isotretinoin treatment.

METHODS

Patients who received systemic isotretinoin treatment between 4 and 8 months were prospectively followed up. In addition to full ophthalmologic examination, MG dysfunction (MGD), noncontact meibography, noninvasive and invasive tear break-up time (TBUT), ocular surface disease index (OSDI), corneal staining, and eyelid margin abnormality scores were recorded before, during, and after treatment.

RESULTS

A total of 88 eyes of 88 patients were included in the study. The right eyes of all the patients were included. The mean age of the patients was 21 ± 2.9 years. Of the 88 patients, 70 (79.6%) were females and 18 (20.4%) were males. Before the treatment, MGD, noncontact meibography, first noninvasive TBUT, mean noninvasive TBUT, invasive TBUT, OSDI, corneal staining, and eyelid margin abnormality scores were 0.29 ± 0.45, 4.93 ± 3.50, 13.78 ± 3.89 s, 14.47 ± 3.09 s, 12.96 ± 3.61 s, 0.54 ± 1.00, 0.04 ± 0.20, and 0.09 ± 0.28, respectively. Twelve months after the end of treatment, the scores were 0.97 ± 0.87 (p < 0.001), 9.62 ± 3.89 (p < 0.001), 11.24 ± 3.52 s (p < 0.001), 12.34 ± 3.02 s (p < 0.001), 11.31 ± 2.90 s (p < 0.001), 1.90 ± 2.44 (p < 0.001), 0.20 ± 0.40 (p < 0.001), and 0.56 ± 0.49 (p < 0.001), respectively.

CONCLUSION

Systemic isotretinoin treatment causes morphological changes in the MGs. However, this treatment may negatively affect the tear film layer of patients. Some of these changes may persist for a long time even if the treatment is discontinued.

CLEAR - Evidence-based contact lens practice

Evidence-based contact lens -->practice involves finding, appraising and applying research findings as the basis for patient management decisions. These decisions should be informed by the strength of the research study designs that address the question, as well as by the experience of the practitioner and the preferences and environment of the patient. This reports reviews and summarises the published research evidence that is available to inform soft and rigid contact lens history and symptoms taking, anterior eye health examination (including the optimised use of ophthalmic dyes, grading scales, imaging techniques and lid eversion), considerations for contact lens selection (including the ocular surface measurements required to select the most appropriate lens parameter, lens modality and material selection), evaluation of lens fit, prescribing (teaching self-application and removal, adaptation, care regimen and cleaning instructions, as well as -->minimising risks of lens wear through encouraging compliance) and an aftercare routine.

Effects of Different Doses of Systemic Isotretinoin on Eyes: A Histopathological and Immunohistochemical Study in Rats

PURPOSE

To evaluate ocular side effects associated with systemic isotretinoin histopathologically.

METHODS

In this multicenter study, a total of 15 male and 15 female rats were randomly divided into 3 equal groups according to the oral dose of isotretinoin they were administered: 0 mg/kg/d (group A), 7.5 mg/kg/d (group B), and 15 mg/kg/d (group C). Biopsy specimens were taken from the globe conjunctiva, cornea, and eyelid conjunctiva. Expression levels of human beta-defensin-1, human beta-defensin-2, toll-like receptor (TLR)-2, and TLR-4 were evaluated by immunohistochemical methods.

RESULTS

The number of goblet cells in eyelid conjunctiva was significantly lower in group B than that in group A and group C (P = 0.002). The sizes of meibomian gland acini were significantly smaller in group B and group C than those in group A (P < 0.001). Fibrosis of eyelid conjunctiva was significantly higher in group C and group B than that in group A (P = 0.002). The levels of staining of TLR-4 in the cornea with group B were significantly lower compared with group C (P = 0.035).

CONCLUSIONS

Our study suggests that isotretinoin in the early period affects eyelid conjunctiva and meibomian glands without affecting the globe conjunctiva and cornea. Occurrence of the initial symptoms of isotretinoin on the eyelids, especially on the meibomian glands, suggests that the symptoms of patients occur because of evaporative dry eye.

Comparative influence of differentiation and proliferation on gene expression in human meibomian gland epithelial cells

We recently discovered that by changing environmental signals, differentiated immortalized human meibomian gland epithelial cells (IHMGECs) de-differentiate into proliferating cells. We also discovered that following exposure to appropriate stimuli, these proliferative cells re-differentiate into differentiated IHMGECs. We hypothesize that this plasticity of differentiated and proliferative IHMGECs is paralleled by very significant alterations in cellular gene expression. To begin to test this hypothesis, we compared the gene expression patterns of IHMGECs during differentiation and proliferation. IHMGECs were cultured for four days in either differentiating or proliferating media. After four days of culture, cells were processed for the analysis of gene expression by using Illumina BeadChips and bioinformatic software. Our study identified significant differences in the expression of more than 9200 genes in differentiated and proliferative IHMGECs. Differentiation was associated with significant increases in the expression of specific genes (e.g. S100 calcium binding protein P; 7,194,386-fold upregulation) and numerous ontologies (e.g. 83 biological process [bp] ontologies with ≥100 genes were upregulated), such as those related to development, transport and lysosomes. Proliferation also led to a significant rise in specific gene expressions (e.g. cathelicidin antimicrobial peptide; 859,100-fold upregulation) and many ontologies (115 biological process [bp] ontologies with ≥100 genes were upregulated), with most of the highly significant ontologies related to cell cycle (z scores > 13.9). Our findings demonstrate that gene expression in differentiated and proliferative IHMGECs is extremely different. These results may have significant implications for the regeneration of HMGECs and the reversal of MG dropout in MG dysfunction.

A review of meibography for a refractive surgeon

Refractive surgery has evolved from being a therapeutic correction of high refractive errors to a cosmetic correction. The expectations associated with such a surgery are enormous and one has to anticipate all possible complications and side-effects that come with the procedure and prepare accordingly. The most common amongst these is post-refractive surgery dry eye of which Meibomian gland dysfunction is a commonly associated cause. We present an understanding of various diagnostic imaging modalities that can be used for evaluating meibomian glands which can also serve as a visual aid for patient understanding. We also describe various common conditions which can silently cause changes in the gland architecture and function which are to be considered and evaluated for.

Isotretinoin and the eye: A review for the dermatologist

Due to the prevalence of acne vulgaris, isotretinoin is one of the most prescribed drugs among physicians and dermatologists. Although exhibiting an adequate safety profile, adverse events secondary to isotretinoin use are common. Before prescribing isotretinoin, physicians usually inquire about pregnancy and perform serologic tests including cholesterol, triglycerides, and liver enzymes. Ocular manifestations are commonly neglected. Despite being generally mild, ocular manifestations related to either topical or systemic isotretinoin may cause important ocular morbidity. The ocular surface is the most affected site within the eye; however, retinal and optic nerve disease also have been documented. Evaporative dry eye disease, which may range from mild to severe, is the most common adverse ocular effect associated with isotretinoin use. The aim of this review is to present an up-to-date overview for the dermatologist about the prevention, diagnosis, and treatment of the ocular side effects of isotretinoin, and when to refer to the eye specialist.

Efficacy of omega-3 fatty acids and punctal plugs in the prevention of isotretinoin-associated ocular surface disease

PURPOSE

To investigate the effects of omega-3 fatty acids and punctal plugs on tear film and ocular surface parameters in patients receiving systemic isotretinoin therapy.

METHODS

This is a prospective randomized study that included 180 eyes of 90 patients who had systemic isotretinoin therapy (120-150 mg/kg for at least 4-6 months). Exclusion criteria: DED according to the diagnostic criteria of TFOS DEWS II. Patients were assigned into three groups; (1) O3FAs/PPs group: A soft preloaded silicone plug was inserted in the inferior punctum of both eyes and received oral O3FAs two capsules twice daily total daily dose of 1040 mg/day for 6 months. (2) PPs group: A soft preloaded silicone plug was inserted in the inferior punctum of both eyes and received oral placebo. (3) Isotretinoin group: No intervention was done. At baseline, 1 week, 1, 3, and 6 months of study, Ocular surface evaluation tests were done in following order: OSDI, tear osmolarity, Schirmer's I test, TBUT, ocular surface staining score, and meibomian gland expression.

PRIMARY OUTCOME MEASURES

The changes in measurement of ocular surface evaluation tests including ocular surface disease index (OSDI), tear film breakup time (TFBUT), corneal staining, tear osmolarity, and meibomian gland expression at 6 months.

RESULTS

There are significant changes between all groups at 6 months follow-up. The ocular surface parameters were better for the PPs and O3FAs/PPs groups than the isotretinoin group. The isotretinoin group showed worsening of ocular surface parameters including a significant decrease of FTBUT and an increase of OSDI score, corneal staining score, tear osmolarity, and meibomian expression score. There was no significant difference in ST1 throughout the whole study in all groups. At 6 months follow-up, there were no statistically significant differences between PPs and O3FAs/PPs groups except meibomian expression score which showed a significant increase in PPs group.

CONCLUSION

Our cohort highlights the beneficial effects of the combination of O3FAs supplementation with PPs in the prevention of isotretinoin-associated OSD in this sample study.

Dihydrotestosterone suppression of proinflammatory gene expression in human meibomian gland epithelial cells

PURPOSE

We discovered that dihydrotestosterone (DHT) decreases the ability of lipopolysaccharide, a bacterial toxin, to stimulate the secretion of leukotriene B4, a potent proinflammatory mediator, by immortalized human meibomian gland epithelial cells (IHMGECs). We hypothesize that this hormone action reflects an androgen suppression of proinflammatory gene activity in these cells. Our goal was to test this hypothesis. For comparison, we also examined whether DHT treatment elicits the same effect in immortalized human corneal (IHC) and conjunctival (IHConj) ECs.

METHODS

Differentiated cells were cultured in media containing vehicle or 10 nM DHT. Cells (n = 3 wells/treatment group) were then processed for RNA isolation and the analysis of gene expression by using Illumina BeadChips, background subtraction, cubic spline normalization and Geospiza software.

RESULTS

Our results demonstrate that DHT significantly suppressed the expression of numerous immune-related genes in HMGECs, such as those associated with antigen processing and presentation, innate and adaptive immune responses, chemotaxis, and cytokine production. DHT also enhanced the expression of genes for defensin β1, IL-1 receptor antagonist, and the anti-inflammatory serine peptidase inhibitor, Kazal type 5. In contrast, DHT had no effect on proinflammatory gene expression in HCECs, and significantly increased 33 gene ontologies linked to the immune system in HConjECs.

CONCLUSIONS

Our findings support our hypothesis that androgens suppress proinflammatory gene expression in IHMGECs. This hormone effect may contribute to the typical absence of inflammation within the human meibomian gland.

Therapeutic Contact Lens for Scavenging Excessive Reactive Oxygen Species on the Ocular Surface

Excessive reactive oxygen species (ROS) play a significant role in the pathogenesis of many eye diseases. Controlling oxidative stress by reducing the amount of ROS is a potential therapeutic strategy for the prevention and treatment of eye diseases, particularly ocular surface diseases. Ceria nanoparticles (CeNPs) have been investigated owing to their efficient ROS-scavenging properties. To overcome the disadvantages of eyedrop administration due to rapid elimination on the surface of the eye and to retain the intrinsic properties of contact lenses, we developed an ROS-scavenging water-soluble CeNP-embedded contact lens (CeNP-CL) for the prevention of ocular surface diseases. The intrinsic ROS-scavenging property of the CeNPs, which mimicked the activities of superoxide dismutase and catalase, was incorporated into polyhydroxyethyl methacrylate-based contact lenses. The CeNP-CL exhibited high transparency and physical properties comparable to those of a commercial contact lens, along with excellent extracellular ROS-scavenging properties. The viabilities of human conjunctival epithelial cells and human meibomian gland epithelial cells were significantly enhanced in the presence of CeNP-CLs, even in media with high H₂O₂ contents (100 and 500 μM). Additionally, the wearing of CeNP-CLs on the eyes had a protective effect in a mouse model when 3% H₂O₂ eyedrops were administered. These results indicate the salvaging effect of the CeNP-CL in a high-ROS environment on the ocular surface, which may be helpful for the treatment of ocular surface diseases.

The Effect of Androgens on Proinflammatory Cytokine Secretion from Human Ocular Surface Epithelial Cells

Purpose: The purpose of this study is to explore the effects of dihydrotestosterone (DHT) on lipopolysaccharide (LPS)-induced proinflammatory cytokine release in human ocular surface epithelial cells exposed to LPS and LPS-binding protein (LBP).Methods: Immortalized human corneal, conjunctival, and meibomian gland epithelial cells were cultured in keratinocyte-free medium. After confluency, they were exposed to a stratification medium Dulbecco's modified Eagle medium (DMEM)/F12 in the presence of fetal bovine serum and were exposed to vehicle, LPS + LBP, or DHT. Culture media were processed for multiplex-bead analysis of specific proinflammatory cytokines including interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-2, IL-4, IL-8, IL-6, IL-10, IL-1β, vascular endothelial growth factor (VEGF)-A. Cytokine concentrations were compared by analysis of variance with Tukey post hoc testing. p < 0.05 was considered statistically significant.Results: The results are LPS + LBP-induced the secretion of IFN-γ, IL-6, IL-10, IL-1β, VEGF-A cytokines in corneal epithelial cells; TNF-α, IL-2, IL-8, IL-6, IL-1β, VEGF-A cytokines in conjunctival epithelial cells; and IL-8, IL-6, IL-1β, VEGF-A cytokines in meibomian gland epithelial cells. When these LPS + LBP-stimulated cells were exposed to DHT for 2 days, it was found that DHT suppressed the secretion of IL-6, IL-10, IL-1β, VEGF-A cytokines in corneal epithelial cells; TNF-α, IL-6, IL-1β, VEGF-A cytokines in conjunctival epithelial cells; and IL-6, IL-1β, VEGF-A cytokines in meibomian gland epithelial cells.Conclusion: LPS + LBP is shown to induce the secretion of certain proinflammatory cytokines from ocular surface and adnexal epithelial cells. DHT showed anti-inflammatory activity by suppressing some of those cytokines in these cell lines.

Histopathology and selective biomarker expression in human meibomian glands

Background/aims

Meibomian gland dysfunction (MGD) is the most common form of evaporative dry eye disease, but its pathogenesis is poorly understood. This study examined the histopathological features of meibomian gland (MG) tissue from cadaver donors to identify potential pathogenic processes that underlie MGD in humans.

Methods

Histological analyses was performed on the MGs in the tarsal plates dissected from four cadaver donors, two young and two old adults, including a 36-year-old female (36F) and three males aged 30, 63 and 64 years (30M, 63M and 64M).

Results

The MGs of 36F displayed normal anatomy and structure, whereas the MGs of 30M showed severe ductal obstruction with mild distortion. The obstruction was caused by increased cytokeratin levels in association with hyperproliferation, but not hyperkeratinisation. In two older males, moderate to severe MG atrophy was noted. Cell proliferation was significantly reduced in the MG acini of the two older donors as measured by Ki67 labelling index (6.0%±3.4% and 7.9%±2.8% in 63M and 64M, respectively) when compared with that of the two younger donors (23.2%±5.5% and 16.9%±4.8% in 30M and 36F, respectively) (p<0.001). The expression patterns of meibocyte differentiation biomarkers were similar in the older and younger donors.

Conclusion

Our histopathological study, based on a small sample size, suggests potentially distinct pathogenic mechanisms in MGD. In the young male adult, hyperproliferation and aberrant differentiation of the central ductal epithelia may lead to the obstruction by overproduced cytokeratins. In contrast, in older adults, decreased cell proliferation in acinar basal epithelia could be a contributing factor leading to MG glandular atrophy.

Mice lacking the epidermal retinol dehydrogenases SDR16C5 and SDR16C6 display accelerated hair growth and enlarged meibomian glands

Retinol dehydrogenases catalyze the rate-limiting step in the biosynthesis of retinoic acid, a bioactive lipid molecule that regulates the expression of hundreds of genes by binding to nuclear transcription factors, the retinoic acid receptors. Several enzymes exhibit retinol dehydrogenase activities in vitro; however, their physiological relevance for retinoic acid biosynthesis in vivo remains unclear. Here, we present evidence that two murine epidermal retinol dehydrogenases, short-chain dehydrogenase/reductase family 16C member 5 (SDR16C5) and SDR16C6, contribute to retinoic acid biosynthesis in living cells and are also essential for the oxidation of retinol to retinaldehyde in vivo Mice with targeted knockout of the more catalytically active SDR16C6 enzyme have no obvious phenotype, possibly due to functional redundancy, because Sdr16c5 and Sdr16c6 exhibit an overlapping expression pattern during later developmental stages and in adulthood. Mice that lack both enzymes are viable and fertile but display accelerated hair growth after shaving and also enlarged meibomian glands, consistent with a nearly 80% reduction in the retinol dehydrogenase activities of skin membrane fractions from the Sdr16c5/Sdr16c6 double-knockout mice. The up-regulation of hair-follicle stem cell genes is consistent with reduced retinoic acid signaling in the skin of the double-knockout mice. These results indicate that the retinol dehydrogenase activities of murine SDR16C5 and SDR16C6 enzymes are not critical for survival but are responsible for most of the retinol dehydrogenase activity in skin, essential for the regulation of the hair-follicle cycle, and required for the maintenance of both sebaceous and meibomian glands.

Neutrophil extracellular traps (NETs) contribute to pathological changes of ocular graft-vs.-host disease (oGVHD) dry eye: Implications for novel biomarkers and therapeutic strategies

PURPOSE

To investigate the role of neutrophil extracellular traps (NETs) and NET-associated proteins in the pathogenesis of oGVHD and whether dismantling of NETs with heparin reduces those changes.

METHODS

Ocular surface washings from oGVHD patients and healthy subjects were analyzed. Isolated peripheral blood human neutrophils were stimulated to generate NETs and heparinized NETs. We performed in vitro experiments using cell lines (corneal epithelial, conjunctival fibroblast, meibomian gland (MG) epithelial and T cells), and in vivo experiments using murine models, and compared the effects of NETs, heparinized NETs, NET-associated proteins and neutralizing antibodies to NET-associated proteins.

RESULTS

Neutrophils, exfoliated epithelial cells, NETs and NET-associated proteins (extracellular DNA, Neutrophil Elastase, Myeloperoxidase, Oncostatin M (OSM), Neutrophil gelatinase-associated lipocalin (NGAL) and LIGHT/TNFSF14) are present in ocular surface washings (OSW) and mucocellular aggregates (MCA). Eyes with high number of neutrophils in OSW have more severe signs and symptoms of oGVHD. NETs (and OSM) cause epitheliopathy in murine corneas. NETs (and LIGHT/TNFSF14) increase proliferation of T cells. NETs (and NGAL) inhibit proliferation and differentiation of MG epithelial cells. NETs enhance proliferation and myofibroblast transformation of conjunctival fibroblasts. Sub-anticoagulant dose Heparin (100 IU/mL) dismantles NETs and reduces epithelial, fibroblast, T cell and MG cell changes induced by NETs.

CONCLUSION

NETs and NET-associated proteins contribute to the pathological changes of oGVHD (corneal epitheliopathy, conjunctival cicatrization, ocular surface inflammation and meibomian gland disease). Our data points to the potential of NET-associated proteins (OSM or LIGHT/TNFSF14) to serve as biomarkers and NET-dismantling biologics (heparin eye drops) as treatment for oGVHD.

An Eyelid Warming Device for the Management of Meibomian Gland Dysfunction

PURPOSE

To determine the effectiveness of the MGDRx EyeBag in managing meibomian gland dysfunction.

METHODS

This was a prospective, randomized, controlled, observer-masked, bilateral eye study that enrolled 29 participants. Participants were randomized into either the EyeBag group or the control group. The EyeBag group used the EyeBag 10minutes 2x/day, and the control group remained on their own dry eye treatment regimen (if applicable). All participants were observed at baseline, 2 weeks (2wk) and 4 weeks (4wk). At 4wk, participants in the EyeBag group were asked to stop using the EyeBag. All participants were seen again at 8 weeks (8wk). Primary outcomes were the Ocular Surface Disease Index (OSDI), Current Symptoms Questionnaire (CSQ), meibomian gland score (MG score), and non-invasive tear breakup time (NIBUT).

RESULTS

Twenty-five participants completed the study (mean age 38±15 years, 7 male). There was a significant change in OSDI over time for the EyeBag group (mean[lower 95% CI, upper 95% CI], baseline: 39.1[31.1,47.0], 2wk: 26.8[19.7,33.9], 4wk: 26.6[16.5,36.7], 8wk: 27.7[18.4,37.0]; p=0.01), but not in the control group (p=0.22), but no significant difference between groups at all time points (all p>0.27). Symptoms immediately improved after conducting the EyeBag based on at-home CSQ scores (Δ=-5.0 points, p<0.01), but not in the control group. For both groups, there was no significant change (p-value EyeBag,p-value control) in MG score (0.21,0.17) and NIBUT (0.49,0.06) over time.

CONCLUSIONS

The EyeBag may relieve symptoms of dry eye, but the effect on meibomian gland function and tear stability when used for only 4 weeks was undetectable.

Repeatability of Meibomian Gland Contrast, a Potential Indicator of Meibomian Gland Function

PURPOSE

Meibomian gland contrast may be a potential indicator of gland health, especially among isotretinoin users. We aimed to develop a repeatable and reliable method for measuring Meibomian gland contrast from meibography images.

METHODS

Lower lid (LL) and upper lid (UL) meibography were captured with the OCULUS Keratograph 5M (OCULUS, Inc) at 2 visits under the following 4 conditions: face centered with room lights on (C), left-turned face (L), right-turned face (R), and face centered with room lights off (CLO). Contrast was measured with Fiji (v2.0.0-rc-59). Coefficient of repeatability and limits of agreement (LOA) were determined using Bland-Altman plots.

RESULTS

A total of 512 meibography images from 16 subjects (age ± SD = 24.8 ± 5.2 years; 13 female patients) were collected. Coefficient of repeatability between visits was 10.5 for UL and 14.9 for LL. Lower and upper LOA, respectively, for UL, compared with condition C, were -10.9 [95% confidence interval (CI), -13.5 to -8.3] and 6.2 (95% CI, 3.6-8.8) for L; -11.0 (95% CI, -13.8 to -8.1) and 7.0 (95% CI, 4.2-9.8) for R; and -9.0 (95% CI, -11.6 to -6.5) and 7.2 (95% CI, 4.7-9.8) for CLO. Lower and upper LOA, respectively, for LL, compared with condition C, were -18.1 (95% CI, -22.6 to -13.5) and 11.0 (95% CI, 6.5-15.5) for L; -15.3 (95% CI, -19.2 to -11.3) and 9.9 (95% CI, 6.0-13.9) for R; and -12.0 (95% CI, -15.1 to -8.8) and 8.2 (95% CI, 5.0-11.3) for CLO.

CONCLUSIONS

Meibomian gland contrast is a repeatable and reliable measure for changes in Meibomian gland contrast greater than 11 in the UL and 18 in the LL.

Hypoxia: A breath of fresh air for the meibomian gland

PURPOSE

Optimal meibomian gland (MG) function is critically important for the health and wellbeing of the ocular surface. We hypothesize that low oxygen (O₂) conditions promote the function of human MG epithelial cells (HMGECs) and that human MGs exist in a relatively hypoxic environment. The purpose of this study was to test our hypotheses.

METHODS

We used human and mouse eyelid segments, and immortalized human MG epithelial cells (IHMGECs) in our studies. To evaluate oxygen (O₂) levels in the mouse MG and vicinity, we injected pimonidazole (pimo), a hypoxia marker, before sacrifice. Human eyelid samples were stained with the hypoxia marker glucose transporter 1 (Glut-1). To determine the effect of low O₂ levels on IHMGECs, we cultured cells under proliferating and differentiating conditions in both normoxic (21% O₂) and hypoxic (3% O₂) conditions for 5-15 days. IHMGECs were evaluated for cell number, neutral lipid content, lysosome accumulation, expression of biomarker proteins and DNase II activity.

RESULTS

Our results demonstrate that human and mouse MGs, but not the surrounding connective tissue, exist in a relatively hypoxic environment in vivo. In addition, our findings show that hypoxia does not influence IHMGEC numbers in basal or proliferating culture conditions, but does stimulate the expression of SREBP-1 in differentiating IHMGECs. Hypoxia also significantly increased DNase II activity, and apparently IHMGEC terminal differentiation.

CONCLUSIONS

Our Results support our hypotheses, and indicate that relative hypoxia promotes MG function.

Evaluation of the effects of isotretinoin for treatment of acne on corneal sensitivity

Purpose

To determine the effect of isotretinoin on corneal sensitivity in acne patients.

Methods

Fifty patients (13 men and 37 women) with a mean age of 23.24 ± 3.4 years were selected among patients receiving isotretinoin (1.0 mg/kg) for acne according to inclusion criteria. The Cochet-Bonnet esthesiometer was used to measure corneal sensitivity (in mm filament length) two times (the measurements were done immediately before starting the medication, then 3 months after that), including 3 measurements each time, between 11 a.m. and 1 p.m. by an experienced operator. The average of the 3 measurements in each time was recorded as the final value. One-way analysis of variance and Chi square were used for quantitative and qualitative comparison of corneal sensitivity before and after isotretinoin use, respectively.

Results

The mean corneal sensitivity was 5.54 ± 0.05 before medication consumption which decreased to 5.41 ± 0.05 after isotretinoin treatment for 3 months (P < 0.005). After controlling the effect of age and sex, the decrease of corneal sensitivity was markedly significant (P = 0.003) as decreased corneal sensitivity was more pronounced at higher ages and in female gender. In non-parametric evaluation, corneal sensitivity was categorized as substantial (5.5–6 mm), intermediate (4.5–5.5 mm), and low (3.5–4.5). About 72% of the participants had substantial corneal sensitivity before drug consumption, which decreased to 60% after 3 months of treatment.

Conclusions

According to the results of this study, corneal sensitivity decreases after three months of treatment with isotretinoin. This decrease is more pronounced at higher ages and in women.

Outcomes of Laser In Situ Keratomileusis and Photorefractive Keratectomy in Patients Taking Isotretinoin

PURPOSE

To determine the functional outcomes of laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) in patients taking isotretinoin, which is contraindicated for these procedures.

DESIGN

Multicenter, retrospective, interventional case series.

METHODS

All patients taking isotretinoin who underwent LASIK or PRK from January 2003 to September 2017 were included (Group 1). Patients were compared with those undergoing LASIK or PRK who had taken isotretinoin previously but not in the previous 6 months (Group 2). Patients were included consecutively.

RESULTS

A total of 113 patients (219 eyes) were included. No significant intraoperative or postoperative complications were found. There were no significant differences between the groups in terms of visual acuity, postoperative spherical equivalent, efficacy index, predictability, or safety index. When only PRK patients were taken into account, the efficacy index (P = .017), postoperative sphere (P = .041), and postoperative astigmatism (P < .001) were better in Group 2, although the difference was not clinically relevant.

CONCLUSIONS

In our experience, LASIK and PRK can be performed effectively and safely in selected patients taking isotretinoin. The absolute exclusion of certain systemic medications should be reconsidered.

Influence of lipopolysaccharide on proinflammatory gene expression in human corneal, conjunctival and meibomian gland epithelial cells

PURPOSE

Lipopolysaccharide (LPS), a bacterial endotoxin, is known to stimulate leuokotriene B4 (LTB4) secretion by human corneal (HCECs), conjunctival (HConjECs) and meibomian gland (HMGECs) epithelial cells. We hypothesize that this LTB4 effect represents an overall induction of proinflammatory gene expression in these cells. Our objective was to test this hypothesis.

METHODS

Immortalized HCECs, HConjECs and HMGECs were cultured in the presence or absence of LPS (15 μg/ml) and ligand binding protein (LBP; 150 ng/ml). Cells were then processed for RNA isolation and the analysis of gene expression by using Illumina BeadChips, background subtraction, cubic spline normalization and GeneSifter software.

RESULTS

Our findings show that LPS induces a striking increase in proinflammatory gene expression in HCECs and HConjECs. These cellular reactions are associated with a significant up-regulation of genes associated with inflammatory and immune responses (e.g. IL-1β, IL-8, and tumor necrosis factor), including those related to chemokine and Toll-like receptor signaling pathways, cytokine-cytokine receptor interactions, and chemotaxis. In contrast, with the exception of Toll-like signaling and associated innate immunity pathways, almost no proinflammatory ontologies were upregulated by LPS in HMGECs.

CONCLUSIONS

Our results support our hypothesis that LPS stimulates proinflammatory gene expression in HCECs and HConjECs. However, our findings also show that LPS does not elicit such proinflammatory responses in HMGECs.

Meibomian glands, meibum, and meibogenesis

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.

TFOS DEWS II pathophysiology report

The TFOS DEWS II Pathophysiology Subcommittee reviewed the mechanisms involved in the initiation and perpetuation of dry eye disease. Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Research in human disease and in animal models has shown that this, either directly or by inducing inflammation, causes a loss of both epithelial and goblet cells. The consequent decrease in surface wettability leads to early tear film breakup and amplifies hyperosmolarity via a Vicious Circle. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity. Increased friction targets damage to the lids and ocular surface, resulting in characteristic punctate epithelial keratitis, superior limbic keratoconjunctivitis, filamentary keratitis, lid parallel conjunctival folds, and lid wiper epitheliopathy. Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. To this end, practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level across the ocular surface, to better determine the severity of dry eye. Areas for future research include the role of genetic mechanisms in non-Sjögren syndrome dry eye, the targeting of the terminal duct in meibomian gland disease and the influence of gaze dynamics and the closed eye state on tear stability and ocular surface inflammation.

TFOS DEWS II iatrogenic report

Dry eye can be caused by a variety of iatrogenic interventions. The increasing number of patients looking for eye care or cosmetic procedures involving the eyes, together with a better understanding of the pathophysiological mechanisms of dry eye disease (DED), have led to the need for a specific report about iatrogenic dry eye within the TFOS DEWS II. Topical medications can cause DED due to their allergic, toxic and immuno-inflammatory effects on the ocular surface. Preservatives, such as benzalkonium chloride, may further aggravate DED. A variety of systemic drugs can also induce DED secondary to multiple mechanisms. Moreover, the use of contact lens induces or is associated with DED. However, one of the most emblematic situations is DED caused by surgical procedures such as corneal refractive surgery as in laser-assisted in situ keratomileusis (LASIK) and keratoplasty due to mechanisms intrinsic to the procedure (i.e. corneal nerve cutting) or even by the use of postoperative topical drugs. Cataract surgery, lid surgeries, botulinum toxin application and cosmetic procedures are also considered risk factors to iatrogenic DED, which can cause patient dissatisfaction, visual disturbance and poor surgical outcomes. This report also presents future directions to address iatrogenic DED, including the need for more in-depth epidemiological studies about the risk factors, development of less toxic medications and preservatives, as well as new techniques for less invasive eye surgeries. Novel research into detection of early dry eye prior to surgeries, efforts to establish appropriate therapeutics and a greater attempt to regulate and oversee medications, preservatives and procedures should be considered.