TFOS DEWS II pathophysiology report

Predictive performance of corneal and lid margin sensitivity for dry eye disease: An investigator-masked, prospective, prognostic accuracy study

PURPOSE

To evaluate the prognostic ability of non-contact esthesiometry corneal and lid margin sensitivity measurements in detecting symptoms and signs of dry eye disease, as defined by the global consensus TFOS DEWS II criteria.

METHODS

A total of 87 community residents (58 females; mean ± SD age, 53 ± 16 years) were recruited in an investigator-masked, prospective, prognostic accuracy study. Dry eye symptomology, tear film parameters, and ocular surface characteristics were evaluated in a single clinical session, and non-contact esthesiometry corneal and lid margin sensitivity measurements performed by an independent masked assessor.

RESULTS

Overall, 49 (56%) participants fulfilled the TFOS DEWS II criteria for dry eye disease, while 57 (66%) exhibited clinical symptoms, and 67 (77%) had positive signs. The prognostic abilities of corneal and lid margin sensitivity measurements were significantly greater than chance for the detection dry eye signs (both p ≤ 0.03), but not for symptoms or overall disease diagnosis (all p > 0.10). The Youden-optimal prognostic cut-offs for corneal and lid margin sensitivity thresholds were both ≥0.8 mbar for the detection of clinical dry eye signs. Lid margin sensitivity demonstrated marginally higher predictive performance than corneal sensitivity (C-statistic, 0.688 versus 0.658), and was significantly correlated with tear film stability, corneal, conjunctival and lid wiper staining (all p < 0.05).

CONCLUSIONS

Corneal and lid margin sensitivity demonstrated moderate prognostic utility for detecting clinical dry eye signs. Future research is warranted to investigate the utility of incorporating non-contact esthesiometry in the workup for dry eye disease and neurotrophic keratopathy.

Effects of age on lacrimal gland bioactive lipids

PURPOSE

Polyunsaturated fatty acids (PUFA) are a source of bioactive lipids regulating inflammation and its resolution.

METHODS

Changes in PUFA metabolism were compared between lacrimal glands (LGs) from young and aged C57BL/6 J mice using a targeted lipidomics assay, as was the gene expression of enzymes involved in the metabolism of these lipids.

RESULTS

Global reduction in PUFAs and their metabolites was observed in aged LGs compared to young controls, averaging between 25 and 66 % across all analytes. ꞷ-6 arachidonic acid (AA) metabolites were all reduced in aged LGs, where the changes in prostaglandin E2 (PGE2) and lipoxin A4 (LXA4) were statistically significant. Several other 5-lipoxygenase (5-LOX) mediated metabolites were significantly reduced in the aged LGs, including D-series resolvins (e.g., RvD4, RvD5, and RvD6). Along with the RvDs, several ꞷ-3 docosahexaenoic acid (DHA) metabolites such as 14-HDHA, neuroprotectin D1 (NPD1), Maresin 2 (MaR2), and MaR 1 metabolite (22-COOH-MaR1) were significantly reduced in aged LGs. Similarly, ꞷ-3 eicosapentaenoic acid (EPA) and its metabolites were significantly reduced in aged LGs, where the most significantly reduced was 18-HEPE. Using metabolite ratios (product:precursor) for specific metabolic conversions as surrogate enzymatic measures, reduced 12-LOX activity was identified in aged LGs.

CONCLUSION

In this study, global reduction of PUFAs and their metabolites was found in the LGs of aged female C57BL/6 J compared to young controls. A consistent reduction was observed across all detected lipid analytes except for ꞷ-3 docosapentaenoic acid (DPA) and its special pro-resolving mediator (SPM) metabolites in aged mice, suggesting an increased risk for LG inflammation.

Comparative effectiveness of nitro dihydrocapsaicin, new synthetic derivative capsaicinoid, and capsaicin in alleviating oxidative stress and inflammation on lipopolysaccharide-stimulated corneal epithelial cells

Loss of tear homeostasis, characterized by hyperosmolarity of the ocular surface, induces cell damage through inflammation and oxidation. Transient receptor potential vanilloid 1 (TRPV1), a sensor for osmotic changes, plays a crucial role as a calcium ion channel in the pathogenesis of hypertonic-related eye diseases. Capsaicin (CAP), a potent phytochemical, alleviates inflammation during oxidative stress events by activating TRPV1. However, the pharmacological use of CAP for eye treatment is limited by its pungency. Nitro dihydrocapsaicin (NDHC) was synthesized with aromatic ring modification of CAP structure to overcome the pungent effect. We compared the molecular features of NDHC and CAP, along with their biological activities in human corneal epithelial (HCE) cells, focusing on antioxidant and anti-inflammatory activities. The results demonstrated that NDHC maintained cell viability, cell shape, and exhibited lower cytotoxicity compared to CAP-treated cells. Moreover, NDHC prevented oxidative stress and inflammation in HCE cells following lipopolysaccharide (LPS) administration. These findings underscore the beneficial effect of NDHC in alleviating ocular surface inflammation, suggesting that NDHC may serve as an alternative anti-inflammatory agent targeting TRPV1 for improving hyperosmotic stress-induced ocular surface damage.

Preliminary study of cyclosporine A/Lifitegrast subconjunctival sustained-release drug membrane in the treatment of dry eyes

BACKGROUND

Dry eyes can cause discomfort. To treat dry eye disease, cyclosporine A (CsA) and Lifitegrast are two eye drugs approved by the U.S. Food and Drug Administration (FDA). However, frequent use of eye drops can be challenging and lead to poor compliance, especially in elderly patients. Therefore, this study aimed to develop a drug sustained-release vector and explore its therapeutic effect in animal models of dry eye.

METHODS

Firstly, drug membranes loaded with both CsA and Lifitegrast using a carrier called poly(lactate-co-ε-caprolactone) (P(LLA-CL)) were prepared and evaluated for their physicochemical properties, release behavior in vitro, and safety in vivo. Next, a rabbit dry eye model using a 0.1% benzalkonium chloride (BAC) solution was developed and treated by drug-loaded micro membranes. We observed and recorded conjunctival hyperemia, corneal staining, corneal edema, corneal neovascularization, conjunctival goblet cells and hematoxylin and eosin (H&E) staining. Finally, we detected the MUC5AC and MMP-9 by immunofluorescence staining and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The composite film released both CsA and Lifitegrast for at least one month. Compared to the blank membrane group, conjunctival hyperemia, corneal fluorescein staining, corneal edema, corneal neovascularization and conjunctival goblet cells recovered faster in the drug membrane group, and the difference was statistically significant. At the molecular level, the drug membrane group showed an increase in mucin density and a significant anti-inflammatory effect.

CONCLUSIONS

The implantation of CsA/Lifitegrast loaded P(LLA-CL) membrane under the subconjunctival of the rabbit eye is safe. The study suggests that this subconjunctival administration could be developed into a minimally invasive delivery system to help patients with dry eye disease who require multiple daily eyedrops but have poor compliance.

A Standardized Extract of Green-Cotyledon Small Black Soybean (EYESOY®) Ameliorates Dry Eye Syndrome in an Animal Model

PURPOSE

Dry eye syndrome is a common ocular disease that causes morbidity, high healthcare burden, and decreased quality of life. In this study, we evaluated the beneficial effects of a standardized extract of small black soybean (EYESOY®) in a benzalkonium chloride (BAC)-induced murine model of dry eye.

METHODS

Experimental dry eye was induced by instillation of 0.02% BAC on the right eye of the Sprague-Dawley rats. Saline solution or EYESOY were administered orally every day for 8 weeks.

RESULTS

EYESOY significantly improved tear volume in the cornea compared with that in the BAC group. Moreover, EYESOY inhibited damage to the corneal epithelial cells and lacrimal glands by suppressing the oxidative and inflammatory responses in a mouse dry eye model. It also increased the goblet cell density and mucin integrity in the conjunctiva.

CONCLUSIONS

Our results suggest that EYESOY has the potential to alleviate dry eye syndrome.

Fostering the unleashing potential of nanocarriers-mediated delivery of ocular therapeutics

Ocular delivery is the most challenging aspect in the field of pharmaceutical research. The major hurdle for the controlled delivery of drugs to the eye includes the physiological static barriers such as the complex layers of the cornea, sclera and retina which restrict the drug from permeating into the anterior and posterior segments of the eye. Recent years have witnessed inventions in the field of conventional and nanocarrier drug delivery which have shown considerable enhancement in delivering small to large molecules across the eye. The dynamic challenges associated with conventional systems include limited drug contact time and inadequate ocular bioavailability resulting from solution drainage, tear turnover, and dilution or lacrimation. To this end, various bioactive-based nanosized carriers including liposomes, ethosomes, niosomes, dendrimer, nanogel, nanofibers, contact lenses, nanoprobes, selenium nanobells, nanosponge, polymeric micelles, silver nanoparticles, and gold nanoparticles among others have been developed to circumvent the limitations associated with the conventional dosage forms. These nanocarriers have been shown to achieve enhanced drug permeation or retention and prolong drug release in the ocular tissue due to their better tissue adherence. The surface charge and the size of nanocarriers (10-1000 nm) are the important key factors to overcome ocular barriers. Various nanocarriers have been shown to deliver active therapeutic molecules including timolol maleate, ampicillin, natamycin, voriconazole, cyclosporine A, dexamethasone, moxifloxacin, and fluconazole among others for the treatment of anterior and posterior eye diseases. Taken together, in a nutshell, this extensive review provides a comprehensive perspective on the numerous facets of ocular drug delivery with a special focus on bioactive nanocarrier-based approaches, including the difficulties and constraints involved in the fabrication of nanocarriers. This also provides the detailed invention, applications, biodistribution and safety-toxicity of nanocarriers-based therapeutcis for the ophthalmic delivery.

Successful management of dry eye disease with a new eye drop formulation combining hyaluronic acid, trehalose, and N-acetyl-aspartyl-glutamic acid (NAAGA)

PURPOSE

To assess the clinical efficacy and safety of T2769, a new preservative-free eye drop combining hyaluronic acid (HA), trehalose and N-acetyl-aspartyl-glutamic acid (NAAGA), in dry eye patients.

PATIENTS AND METHODS

This was a multicenter, non-comparative, open-label study. After a run-in period with NaCl 0.9% solution, 62 patients with moderate-to-severe dry eye disease (DED) were included and treated with T2769, 3 to 6 times/day for 42 days. The primary efficacy endpoint was the change in global ocular symptomatology assessed on a visual analog scale between Day 1 (D1) and D42. Other efficacy endpoints included ocular surface disease index (OSDI), soothing sensation, individual dry eye symptoms, conjunctival hyperemia, global ocular staining, tear break-up time, Schirmer test, and global efficacy assessed by the investigator. Safety was assessed throughout the study.

RESULTS

A marked reduction in ocular symptomatology was observed from D1 to D42 with a mean change of -55.9±23.1mm (P<0.001). This was accompanied by a mean change in OSDI score from baseline of -44.6±15.9 (P<0.001) and a substantial soothing sensation in 82.3% of patients. Clinically significant improvements were observed for all ocular symptoms (mainly burning/irritation, stinging/pain, feeling of ocular dryness, foreign body sensation, itching/pruritus). Conjunctival hyperemia significantly decreased in 96.8% of patients (56.5% displayed no conjunctival hyperemia at D42 versus 0% at baseline). All signs and symptoms improved by D14 and further improved at D42. Investigators assessed the ocular efficacy of T2769 as very satisfactory or satisfactory for 91.9% of patients at D42. T2769 was well tolerated, with no ocular adverse events and only a few ocular symptoms upon instillation.

CONCLUSION

Management of moderate-to-severe DED patients with the new formulation T2769, combining NAAGA to HA and trehalose, led to rapid and significant improvements in dry eye signs and symptoms with good tolerability.

Oridonin ameliorates ocular surface inflammatory responses by inhibiting the NLRP3/caspase-1/GSDMD pyroptosis pathway in dry eye

Chronic inflammation is one of the central drivers in the development of dry eye disease (DED), in which pyroptosis induced by the NLRP3/caspase-1/gasdermin D (GSDMD) pathway plays a key role. This pathway has become a major target for the treatment of a variety of inflammatory disorders. Oridonin (Ori) is a naturally occurring substance with anti-inflammatory properties obtained from Rabdosia rubescens. Whether Ori can exert an anti-inflammatory effect on DED, and its anti-inflammatory mechanism of action, are still unknown. This experiment is intended to investigate the impact of Ori on the hyperosmolarity-induced NLRP3/caspase-1/GSDMD pyroptosis pathway in immortalized human corneal epithelial (HCE-T) cells, as well as its efficacy and mechanism of action on ocular surface injury in DED mice. Our study showed that Ori could inhibit hyperosmotic-induced pyroptosis through the NLRP3/caspase-1/GSDMD pathway in HCE-T cells, and similarly, Ori inhibited the expression of this pathway in DED mice. Moreover, Ori was protective against hyperosmolarity-induced HCE-T cell damage. In addition, we found that the morphology and number of HCE-T cells were altered under culture conditions of various osmolarities. With increasing osmolarity, the proliferation, migration, and healing ability of HCE-T cells decreased significantly, and the expression of N-GSDMD was elevated. In a mouse model of DED, Ori application inhibited the expression of the NLRP3/caspase-1/GSDMD pyroptosis pathway, improved DED signs and injury, decreased corneal sodium fluorescein staining scores, and increased tear volume. Thus, our study suggests that Ori has potential applications for the treatment of DED, provides potential novel therapeutic approaches to treat DED, and provides a theoretical foundation for treating DED using Ori.

Quantitative Assessment of Lid Margin Vascularity Using Swept-Source Optical Coherence Tomography Angiography

Purpose

To evaluate the ability of swept-source optical coherence tomography angiography (SS-OCTA) to assess lid margin vascularity.

Methods

This prospective, cross-sectional trial enrolled 125 participants, including 15 control subjects and 110 meibomian gland dysfunction (MGD) patients. Lid margin blood flow density (LMBFD) was obtained using SS-OCTA. LMBFD was assessed for repeatability in 54 of 125 participants and for reproducibility in 23 of 125 participants. The efficacy of LMBFD was validated in the 125 participants, who were divided into mild (n = 46), moderate (n = 42), and severe groups (n = 37) according to the lid margin vascularity severity shown in the slit-lamp photographs. Correlations between LMBFD and MG-related parameters, such as ocular surface disease index (OSDI), fluorescein tear break-up time (FTBUT), cornea fluorescein staining (CFS), lid margin score (LMS), and meibomian gland expressibility (ME), were analyzed in all 125 participants.

Results

Repeatability and reproducibility coefficients were satisfactorily high in the scan mode with a scan area of 6 mm × 6 mm (intraclass correlation coefficient [ICC] repeatability = 0.905; ICC reproducibility = 0.986) and a scan area of 9 mm × 9 mm (ICC repeatability = 0.888; ICC reproducibility = 0.988). The LMBFD gradually increased in the mild, moderate, and severe groups (P < 0.001). LMBFD was significant correlated with OSDI (r = 0.290, P = 0.001), FTBUT (r = -0.195, P = 0.030), CFS (r = 0.352, P < 0.001), ME (r = 0.191, P = 0.033), and LMS (r = 0.370, P < 0.001).

Conclusions

LMBFD may be a noninvasive, repeatable, reproducible, and efficient index for the quantitative evaluation of eyelid margin vascularity in the future.

Translational Relevance

We demonstrated that SS-OCTA has the potential to evaluate the eyelid margin vascularity in MGD patients and guide future treatment strategies in clinics.

Patient-Reported Dry Eye Treatment and Burden of Care

OBJECTIVES

Dry eye is a common condition that can decrease the quality of life. This survey-based study of persons with dry eye investigated self-reported treatments (initial, current), out-of-pocket expenses, time spent on self-management, sources of care, and sources of information about their condition.

METHODS

Online dry eye newsletters and support groups were emailed a link to an electronic survey asking members to participate. Survey respondents were not required to answer every question.

RESULTS

In total, 639 persons with self-reported dry eye responded (86% women, 14% men [n=623]; mean ± SD age, 55 ± 14 years [n=595]). Artificial tears were the most reported intervention (76% initially, 71% currently). The median (interquartile range) out-of-pocket treatment cost annually was $500 ($200-$1,320 [n=506]). In addition, 55% (n=544) estimated 5 to 20 min daily on self-management; 22% spent an hour or more. Ophthalmologists provided most dry eye care (67%, n=520). Only 48% (n=524) reported that their primary source of dry eye information came from their eye care clinician.

CONCLUSIONS

Artificial tears are the primary treatment for dry eye. Ophthalmologists provide most dry eye care, but half of patients report that their eye care provider is not their primary source of information. Almost one fourth of patients spend an hour or more daily on treatments.

Topical glaucoma medications - Possible implications on the meibomian glands

One of the most common causes of blindness on a global scale is glaucoma. There is a strong association between glaucoma and increased intraocular pressure (IOP). Because of this, adequate IOP-lowering is the most important treatment strategy, mostly through topical eyedrops. Well-functioning meibomian glands are paramount for maintaining a stable tear film, and their dysfunction is the most common cause of dry eye disease. There is a growing concern that both topical glaucoma medications themselves and their added preservatives damage the meibomian glands, and consequently, the ocular surface. Preserved topical glaucoma medications appear to cause dysfunction and atrophy of the meibomian glands. Upon comparison, preserved formulations caused more symptoms of dry eye, tear film instability, inflammatory changes and meibomian gland dropout than the preservative-free counterpart. However, although seemingly less detrimental, unpreserved alternatives may diminish glandular efficacy, and, depending on the active ingredient, lead to glandular death. This negatively impacts quality of life, adherence to treatment regimens and prognosis. In this review, we explore the available evidence regarding the effects of IOP-lowering eye drops on the meibomian glands.

Impact of thermo-mechanical skin treatment on refraction and keratometry in patients with dry eye disease and the implications for cataract surgery

PURPOSE

To determine the changes in keratometry measurements and refraction in patients having the thermo-mechanical periorbital skin treatment, Tixel®, to treat dry eye disease (DED).

METHODS

A multi-centre, prospective, non-masked study was conducted. DED patients were recruited in 3 international centres and were evaluated in 5 visits separated by an interval of 2 weeks except for the last visit which took place after 18 weeks from visit 1. The same clinical examination was performed at all visits: OSDI questionnaire, tear stability, keratometry, best corrected visual acuity and refraction. Tixel® treatment was applied at the first 3 visits.

RESULTS

89 participants (24 males/65 females; mean age: 55.0 ± 14.2 years) were included: 20 presented moderate DED symptoms and 69 severe DED symptoms. Significant differences were found for the spherocylindrical refraction (vector analysis) between visit 1 and visits 2 and 3. Following cumulative analysis, 11.86 % and 16.94 % of participants had more than 0.5 dioptre (D) change in mean keratometry and keratometric astigmatism, respectively, at 3 months post-treatment. A total of 5.40 % had a sphere and cylinder change greater than 0.50D and 16.21 % had the axis changed more than 10 degrees (vector analysis). These changes were particularly significant in patients with severe DED symptoms.

CONCLUSIONS

Keratometry readings and refraction can change following thermo-mechanical skin treatment for DED, especially in those patients with severe DED symptoms. This should be considered as potential errors in intraocular lens calculations may be induced.

The bioengineering application of hyaluronic acid in tissue regeneration and repair

The multifaceted role of hyaluronic acid (HA) across diverse biomedical disciplines underscores its versatility in tissue regeneration and repair. HA hydrogels employ different crosslinking including chemical (chitosan, collagen), photo- initiation (riboflavin, LAP), enzymatic (HRP/H2O2), and physical interactions (hydrogen bonds, metal coordination). In biophysics and biochemistry, HA's signaling pathways, primarily through CD44 and RHAMM receptors, modulate cell behavior (cell migration; internalization of HA), inflammation, and wound healing. Particularly, smaller HA fragments stimulate inflammatory responses through toll-like receptors, impacting macrophages and cytokine expression. HA's implications in oncology highlight its involvement in tumor progression, metastasis, and treatment. Elevated HA in tumor stroma impacts apoptosis resistance and promotes tumor growth, presenting potential therapeutic targets to halt tumor progression. In orthopedics, HA's presence in synovial fluid aids in osteoarthritis management, as its supplementation alleviates pain, enhances synovial fluid's viscoelastic properties, and promotes cartilage integrity. In ophthalmology, HA's application in dry eye syndrome addresses symptoms by moisturizing the eyes, replenishing tear film deficiencies, and facilitating wound healing. Intravitreal injections and hydrogel-based systems offer versatile approaches for drug delivery and vitreous humor replacement. For skin regeneration and wound healing, HA hydrogel dressings exhibit exceptional properties by promoting moist wound healing and facilitating tissue repair. Integration of advanced regenerative tools like stem cells and solubilized amnion membranes into HA-based systems accelerates wound closure and tissue recovery. Overall, HA's unique properties and interactions render it a promising candidate across diverse biomedical domains, showcasing immense potentials in tissue regeneration and therapeutic interventions. Nevertheless, many detailed cellular and molecular mechanisms of HA and its applications remain unexplored and warrant further investigation.

Influential Signs of Dry Eye-Related Ocular Symptoms in Participants With Unstable Tear Film

PURPOSE

The aim of this study was to investigate the factors influencing dry eye disease (DED)-related ocular symptoms in participants with short fluorescein tear break-up time (FTBUT).

METHODS

This cross-sectional study included 82 participants with short FTBUT (<10 seconds). Examinations included Ocular Surface Disease Index (OSDI), FTBUT, average noninvasive tear break-up time (NIBUTave), lid wiper epitheliopathy, lipid layer thickness, blink rate, partial blink, tear meniscus height, and meibomian gland (MG) evaluation which included ratio of residual MG area (RMGA) and MG grade in tarsal plates. One-way analysis of variance was used to detect differences between symptomatic tear film instability group (FTBUT <5 s, OSDI ≥13), asymptomatic tear film instability group (FTBUT <5 s, OSDI <13), and control group (FTBUT ≥5 s, OSDI <13). A bivariate correlation, partial correlation, and multiple linear regression analyses were used to identify major factors. Only the right eye was included.

RESULTS

Among the participants with FTBUT <5 seconds, symptomatic group showed less upper RMGA ( P < 0.001) and NIBUTave ( P = 0.010). OSDI was negatively associated with upper RMGA ( r = -0.450, P < 0.001) and NIBUTave ( r = -0.414, P = 0.001), and positively associated with upper MG grade ( r = 0.277, P = 0.027). Linear regression analysis showed that the upper RMGA significantly affected OSDI (B = -41.895, P = 0.001), while not significantly correlated with age, upper MG grade, and NIBUTave.

CONCLUSIONS

The upper RMGA might be the main factor affecting DED-related discomfort in participants with unstable tear film, indicating an early ocular change in DED.

Efficacy of RCI001 as a therapeutic candidate of dry eye disease in a modified mixed dry eye model

BACKGROUND

To evaluate the therapeutic effects of topical RCI001 (RCI) and compare its efficacy with that of 1% prednisolone acetate (PDE) and 5% Lifitegrast in a modified mixed dry eye disease (DED) model.

METHODS

The environmental DED model was induced in BALB/c mice in a dry chamber with scopolamine. The eyes of the mice were treated topically with phosphate buffered saline (PBS), PDE, Lifitegrast or RCI twice daily for 1 week. Ocular surface staining (OSS), tear secretion, inflammatory cytokines in the ocular surface and lacrimal gland, and immunofluorescence staining in the conjunctiva and cornea(CC) were assessed.

RESULTS

The RCI group demonstrated better improvement of OSS and tear secretion than the PBS group (OSS, PBS: 13.0 ± 1.6, RCI: 9.4 ± 3.0; tear secretion, PBS: 5.0 ± 0.4 mm, RCI: 7.0 ± 0.3 mm, each P < 0.001) and better clinical efficacy than PDE and Lifitegrast groups on Day 7 (improvement rate of OSS, RCI: 32.45%, Lifitegrast: 13.13%, PDE: 12.25%). The RCI group resulted in significantly lower expression of oxidative stress markers in the CC than the PBS group (4-HNE, NOX2, and NOX4 in the conjunctiva; NOX2 in the cornea, each P < 0.05). However, the PDE and Lifitegrast groups did not show significant differences compared with the PBS group. There were no significant differences of inflammatory cytokines in the ocular surface and lacrimal gland between all groups.

CONCLUSION

Topical RCI001 showed excellent therapeutic effects in environmental DED models by stimulating tear secretion, modulating oxidative stress and improving corneal epithelial healing compared to 1% PDE and 5% Lifitegrast.

Immunopathological mechanisms and clinical manifestations of ocular graft-versus-host disease following hematopoietic stem cell transplantation

Graft-versus-host disease is among the most common clinical complications following allogeneic hematopoietic stem cell transplantation. It causes inflammation-mediated destruction and dysfunction of various organ systems including ocular tissues in 60-90% of the patients and is termed ocular GVHD (oGVHD). In oGVHD, donor-derived T-cells recognize host antigens as foreign, resulting in immune dysregulation, inflammation and fibrosis of lacrimal glands, meibomian glands, cornea, and conjunctiva. The clinical presentation in oGVHD patients range from mild dry eye symptoms to catastrophic inflammation mediated pathological changes which can cause corneal perforation and blindness. In this review article, we provide detailed insights into the impact of mucosal barrier disruption, the afferent and efferent phases of immunological response involving activation of antigen presenting cells and T cells, respectively. We evaluate the evidence outlining the effector phase of the disease leading to cellular destruction and eventually fibrosis in patients with oGVHD. Finally, we discuss the well-established criteria for the diagnosis of oGVHD.

Effect of Artificial Tears on Preoperative Keratometry and Refractive Precision in Cataract Surgery

Purpose

The primary objective was to investigate if treatment with artificial tears affected the variability of keratometry measurements for subjects with dry eyes prior to cataract surgery. The secondary objectives were to investigate whether treatment with artificial tears improved refractive precision and whether subjects with non-dry eyes had better refractive precision than subjects with dry eyes.

Design

Prospective randomized controlled trial with three arms.

Patients and methods

Dry eye diagnostics according to DEWS II were performed, and subjects with dry eyes were randomized to no treatment (group A1) or treatment with artificial tears two weeks prior to cataract surgery (group A2), with the third group (Group B, non-dry eyes) as a control. Keratometry was performed twice at baseline and twice after two weeks at the time of cataract surgery with three different optical biometers. The change in mean variability of keratometry (average K and magnitude of vector differences) and percentages of outliers after two weeks versus baseline were compared for group A2. The refractive and astigmatism prediction errors were calculated eight weeks after cataract surgery and compared for all three groups.

Results

One hundred thirty-one subjects were available for analysis. There was no statistically significant difference in the mean variability of keratometry or percentages of outliers for group A2 from baseline to the time of cataract surgery. There was no statistically significant difference in refractive precision (absolute error and astigmatism prediction error) between any groups.

Conclusion

Subjects with dry eyes (treated and non-treated) achieved the same refractive precision and percentages of outliers as subjects with non-dry eyes. Treatment with artificial tears for two weeks appeared inadequate to significantly affect variability in biometric measurements for patients with dry eyes prior to cataract surgery. DEWS II criteria for DED may not be optimal in a cataract setting.

Disrupted mitochondrial transcription factor A expression promotes mitochondrial dysfunction and enhances ocular surface inflammation by activating the absent in melanoma 2 inflammasome

PURPOSE

Severe dry eye disease causes ocular surface damage, which is highly associated with mitochondrial dysfunction. Mitochondrial transcription factor A (TFAM) is essential for packaging mitochondrial DNA (mtDNA) and is crucial for maintaining mitochondrial function. Herein, we aimed to explore the effect of a decreased TFAM expression on ocular surface damage.

METHODS

Female C57BL/6 mice were induced ocular surface injury by topical administrating benzalkonium chloride (BAC). Immortalized human corneal epithelial cells (HCECs) were stimulated by tert-butyl hydroperoxide (t-BHP) to create oxidative stress damage. HCECs with TFAM knockdown were established. RNA sequencing was employed to analyze the whole-genome expression. Mitochondrial changes were measured by transmission electron microscopy, Seahorse metabolic flux analysis, mitochondrial membrane potential, and mtDNA copy number. TFAM expression and inflammatory cytokines were determined using RT-qPCR, immunohistochemistry, immunofluorescence, and immunoblotting.

RESULTS

In both the corneas of BAC-treated mice and t-BHP-induced HCECs, we observed impaired TFAM expression, accompanied by mitochondrial structure and function defects. TFAM downregulation in HCECs suppressed mitochondrial respiratory capacity, reduced mtDNA content, induced mtDNA leakage into the cytoplasm, and led to inflammation. RNA sequencing revealed the absent in melanoma 2 (AIM2) inflammasome was activated in the corneas of BAC-treated mice. The AIM2 inflammasome activation was confirmed in TFAM knockdown HCECs. TFAM knockdown in t-BHP-stimulated HCECs aggravated mitochondrial dysfunction and the AIM2 inflammasome activation, thereby further triggering the secretion of inflammatory factors such as interleukin (IL) -1β and IL-18.

CONCLUSIONS

TFAM reduction impaired mitochondrial function, activated AIM2 inflammasome and promoted ocular surface inflammation, revealing an underlying molecular mechanism for ocular surface disorders.

Clinical Efficacy of 2% Rebamipide in Patients With Video Display Terminal-Associated Dry Eye Disease: A Prospective, Randomized, Double-Blinded Study

PURPOSE

To compare the effects of 2% rebamipide clear solution and 0.1% sodium hyaluronate eye drops in patients with visual display terminal (VDT)-related dry eye disease (DED).

DESIGN

Prospective, randomized, double-blinded Study.

METHODS

This was a prospective, double-blind, and randomized controlled study. Patients with VDT-related DED were randomly allocated to a 2% rebamipide (REB) group or a 0.1% sodium hyaluronate (HYA) group (4 times/day for 4 weeks). The ocular surface disease index (OSDI), dry eye questionnaire-5 (DEQ-5), Placido disk-tear film analyzer, fluorescein-stained tear break-up time (FBUT), ocular surface staining score, and Schirmer 1 test were examined before and after the instillation of drug.

RESULTS

A total of 56 eyes of 28 patients (28 eyes of 14 patients in each group) were included. There were no significant differences in the baseline data. The OSDI, DEQ-5, FBUT, and conjunctival erosion scores improved significantly in both groups after treatment. In the REB group, corneal staining and bulbar nasal redness scores also improved significantly after treatment (P<0.001 and 0.036, respectively), whereas no significant differences were found in these parameters in the HYA group (P=0.326 and 0.118, respectively). The REB group showed a significantly larger decrease in the corneal staining score than the HYA group (P=0.016). No adverse reactions were observed.

CONCLUSIONS

A 2% rebamipide clear solution effectively improved the symptoms and signs in patients with VDT-related DED and was superior to 0.1% sodium hyaluronate ophthalmic solution in improving corneal epithelial damage, making it a safe and effective treatment option for VDT-related DED.

Prophylactic Therapy for Long-Term Ocular Discomfort After Cataract Surgery

PURPOSE

The cataract surgery dissatisfaction rate is 20% to 35% due to ocular surface discomfort. We investigate the ocular surface discomfort after surgical failure as a consequence of age-related parainflammation. We also aim to prevent it by immune-modulating prophylactic management.

METHODS

Monocentric clinical trial realized in a teaching hospital. Prospective, randomized, open-label, unmasked clinical trial. One hundred patients diagnosed with cataracts underwent phacoemulsification surgery. Groups A (<65 years; n = 25) and B (>75 years; n = 25) received surgery only. Groups C and D (both >75 years and both n = 25) used cyclosporine A 0.1% cationic emulsion (CE) eye drops or CE lubricating eye drops (both twice daily), respectively, for 30 days before surgery. Patients were followed up 90 days after surgery. The primary outcome was postoperative ocular surface failure; secondary outcomes examined the influence of prophylactic cyclosporine A 0.1% CE therapy on ocular surface outcomes.

RESULTS

Group B demonstrated greater severity regarding ocular surface signs and symptoms throughout the study period, versus all other groups. Signs/symptoms were typically lower in Group A. Group C achieved significant reductions in conjunctival Symptom Assessment in Dry Eye values ( P < 0.05), conjunctival hyperemia severity ( P < 0.01), and meibomian gland dysfunction ( P < 0.001) at Day 45, versus Group B, and tear break-up time was increased ( P < 0.001). Ocular surface inflammatory marker transcription (HLADR, intercellular adhesion molecule 1 [ICAM-1], and interleukin 6 [IL-6]) was significantly downregulated in Group C, versus Group B, at 90 days ( P < 0.05).

CONCLUSIONS

Cataract surgery induced ocular surface system failure with a clinically significant persistent inflammatory status (InflammAging) in patients older than 75 years. Prophylactic cyclosporine A 0.1% CE eye drops were associated with improved ocular surface homeostasis and reductions in inflammatory markers.

Tear film hTERT and corneal nerve characteristics in dry eye disease

CLINICAL RELEVANCE

The behaviour of human telomerase reverse transcriptase (hTERT) in tears reflects its role in maintaining the ocular surface homoeostasis, as it is increased after the initial fitting of contact lenses and post-overnight lid closure.

BACKGROUND

hTERT has been shown to respond to cellular stress in neurodegenerative diseases and to enhance axonal regeneration after peripheral axotomy in an animal model. This work investigated whether the behaviour of hTERT in the tear film reflects ocular surface inflammation and neuronal changes in the presence of dry eye disease.

METHODS

Flush tears were collected from 18 participants with dry eye disease (14 females, 4 males, mean age 34.7 ± 5.2 years) and from 18 healthy participants without dry eye disease (8 females, 10 males, mean age 31.9 ± 5.8 years). Dry eye disease status was defined using the TFOS DEWS II diagnostic criteria. hTERT levels in tears were measured using enzyme-linked immunosorbent assays. Confocal images were taken at the level of the subbasal nerve plexus at the central cornea and at the inferior whorl, and the densities of corneal immune cells were evaluated as well as corneal nerve morphology metrics using a fully automated technique (University of Manchester, United Kingdom).

RESULTS

In participants with dry eye disease, hTERT levels were significantly higher compared to controls (median [interquartile range]: 434 [320-600] ng/ml, and 184 [42-390] ng/ml, respectively, p = 0.01). Increased nerve fibre width at the inferior whorl, was seen in those with dry eyes (0.0219 [0.0214-0.0236] mm/mm compared to controls 0.0217 [0.0207 0.0222] p < 0.001), but no significant differences were found in the density of corneal immune cells.

CONCLUSIONS

hTERT levels were elevated in participants with dry eye disease, and this was accompanied by increased nerve thickness in the inferior cornea. The hTERT response may reflect the stress induced to the ocular surface and corneal nerves due to having dry eye disease.

Bilateral Sutureless Application of Human Dehydrated Amniotic Membrane with a Specialised Bandage Contact Lens for Moderate-to-Severe Dry Eye Disease: A Prospective Study with 1-Month Follow-Up

Purpose

To assess changes in symptoms and ocular surface signs following a bilateral sutureless treatment of dehydrated amniotic membrane (dAM) under a specialised bandage contact lens (sBCL) in patients with moderate-to-severe dry eye disease (DED).

Patients and Methods

In this prospective pre-post interventional study, 35 patients diagnosed with moderate-to-severe DED, with an Ocular Surface Disease Index (OSDI) score >30 on current treatment, were enrolled. Assessments were conducted at baseline (day -30), after 30 days run-in with no additional treatment (day 0 - control), and 30 days post sBCL+dAM treatment (day 30 - treatment). Intervention involved two successive bilateral 4-5 day sutureless applications of dAM (17mm diameter, with a 6 mm central aperture, Omnigen® VIEW) under an 18mm sBCL (OmniLenz®). Symptomatology and ocular signs were measured using OSDI, Dry Eye Questionnaire-5 (DEQ-5), Symptom Assessment iN Dry Eye (SANDE), and other ocular surface health indicators including non-invasive breakup time, corneal and conjunctival staining, and lid wiper epitheliopathy length and width (LWE).

Results

While symptomatology remained stable during the 30-day no-treatment run-in, 1-month post-dAM treatment, there was a significant reduction in OSDI scores (from 55.8 to 32.3, p<0.001), DEQ-5 (from 14.6 to 10.0, p<0.001), SANDE frequency (from 65.2 to 43.6, p<0.001), and SANDE severity (from 59.8 to 41.1, p<0.001). Additionally, there was a notable decrease in the width of LWE staining, from grade 2 (50-75% of the lid wiper) to grade 1 (25-50% of the lid wiper) (p=0.011).

Conclusion

A bilateral 8-10-day treatment duration with dAM applied with sBCL demonstrated a 31 to 42% improvement in symptomatology and a decrease in ocular surface signs of mechanical stress. This innovative bilateral treatment approach offers a promising treatment modality for patients with refractory moderate-to-severe DED.

Safety and Efficacy of Topical Vitamin D in the Management of Dry Eye Disease Associated With Meibomian Gland Dysfunction: A Placebo-Controlled Double-Blind Randomized Controlled Trial

PURPOSE

The aim of this study was to investigate the safety and efficacy of topical vitamin D in the management of dry eye disease associated with meibomian gland dysfunction (MGD).

METHODS

In this randomized controlled trial, patients with symptomatic MGD were divided into 2 groups to receive topical vitamin D drops or placebo in their randomized eyes. The exclusion criteria consisted of patients with vitamin D deficiency, previous ocular surgery, and patients with ocular diseases affecting the tear film. Patients and researchers were masked to the study groups. The outcomes included the score of Dry Eye Questionnaire (DEQ) 5 and Ocular Surface Disease Index (OSDI), corneal and conjunctival staining score, tear breakup time (TBUT), Schirmer, and MG expressibility score evaluated at baseline and weeks 4 and 8.

RESULTS

Twenty-eight eyes of 28 patients were recruited in each group. In addition to the improvement of subjective parameters in both groups, there was a statistically significantly greater improvement in the vitamin D group compared with control for average scores of OSDI (13.38 ± 7.32 vs. 27.94 ± 7.49) and DEQ5 (9.67 ± 1.86 vs. 14.14 ± 2.45) at week 8 (Ps <0.001). In addition, a significant improvement in TBUT and Schirmer test was observed in both groups in weeks 4 and 8 ( P value <0.05). There was a significant difference between the treatment and control groups after 8 weeks for OSDI, DEQ5, Schirmer, TBUT, corneal fluorescein staining, and MG expressibility score ( P value <0.05).

CONCLUSIONS

The preliminary results of this randomized controlled trial suggested that use of topical vitamin D drops with a lipid vehicle could be safe and might significantly improve the symptoms and signs of dry eye associated with MGD.

Diamond Bur Microblepharoexfoliation Combined with Intense Pulse Light and Meibomian Gland Expression for Evaporative Dry Eye: A Short-term Controlled Clinical Trial

INTRODUCTION

To assess the efficacy and safety of the combination of microblepharoexfoliation (MBE), intense pulse light (IPL) and meibomian gland expression (MGX) for treatment of meibomian gland dysfunction (MGD).

METHODS

This was a prospective, parallel-control trial conducted from April 2022 to January 2023. Participants were assigned to receive either three sessions of MBE-IPL-MGX treatment and home-based therapy (treatment group) or home-based therapy alone (control group). Outcome measures were assessed at baseline and after 2-month follow-up.

RESULTS

Seventy eyes of 70 patients were enrolled. MBE-IPL-MGX treatment achieved better improvements than home-based therapy in ocular surface disease index (OSDI) and symptom assessment in dry eye (SANDE) scores, noninvasive tear film break-up time (NIBUT), lipid layer grade (LLG), loss area meibomian gland (LAMG) and meibomian gland yielding secretion score (MGYSS). The mean differences between the two groups were as follows: OSDI (- 11.23 ± 4.68 points, P < 0.001), SANDE (- 24.63 ± 13.41 points, P < 0.001), NIBUT (1.3 ± 1.57 s, P = 0.033), LLG (0.4 ± 0.04 points, P = 0.003), LAMG (- 2.85 ± 1.69%, P = 0.023) and MGYSS (7.5 ± 2.32 points, P < 0.001). In addition, the increment (Δ) of MGYSS after MBE-IPL-MGX treatment was significantly higher in MGD grades 2 and 3 (all P < 0.001).

CONCLUSIONS

MBE-IPL-MGX treatment is an effective and well-tolerated procedure that improves dry eye symptoms and signs as well as meibomian gland secretions in patients with MGD. In addition, this treatment is recommended for MGD grades 2 and 3.

Sex Differences in the Prevalence of Meibomian Gland Dysfunction: A Mini Review

PURPOSE

In this review, we aimed to investigate the literature on sex-specific prevalence of meibomian gland dysfunction (MGD) and to determine whether women or men are more at risk for MGD.

METHODS

A search was conducted on PubMed using the terms: (Sex OR Gender OR prevalence) AND (Meibomian gland).

RESULTS

Twenty-four relevant studies on MGD prevalence were identified, including 10 population-based and 14 hospital-based studies. Among the population-based studies, five studies reported higher rates among men, three studies found no differences, and one study observed higher rates among women. In the hospital-based studies, 10 studies reported no difference, two found higher rates among men, and one found higher among women. In the reviewed literature, there was a considerable variation between studies in terms of quality, sample size, age ranges, diagnostic criteria.

CONCLUSIONS

While most of the population-based studies suggest a higher prevalence among men, the majority of clinic-based studies show no significant difference. Further research with larger samples and standardized criteria is needed to determine whether men are indeed more susceptible to MGD.

Transient Receptor Potential Vanilloid-1 Channels Facilitate Axonal Degeneration of Corneal Sensory Nerves in Dry Eye

Corneal nerve impairment contributes significantly to dry eye disease (DED) symptoms and is thought to be secondary to corneal epithelial damage. Transient receptor potential vanilloid-1 (TRPV1) channels abound in corneal nerve fibers and respond to inflammation-derived ligands, which increase in DED. TRPV1 overactivation promotes axonal degeneration in vitro, but whether it participates in DED-associated corneal nerve dysfunction is unknown. To explore this, DED was surgically induced in wild-type and TRPV1-knockout mice, which developed comparable corneal epithelial damage and reduced tear secretion. However, corneal mechanosensitivity decreased progressively only in wild-type DED mice. Sensitivity to capsaicin (TRPV1 agonist) increased in wild-type DED mice, and consistently, only this strain displayed DED-induced pain signs. Wild-type DED mice exhibited nerve degeneration throughout the corneal epithelium, whereas TRPV1-knockout DED mice only developed a reduction in the most superficial nerve endings that failed to propagate to the deeper subbasal corneal nerves. Pharmacologic TRPV1 blockade reproduced these findings in wild-type DED mice, whereas CD4+ T cells from both strains were equally pathogenic when transferred, ruling out a T-cell-mediated effect of TRPV1 deficiency. These data show that ocular desiccation triggers superficial corneal nerve damage in DED, but proximal propagation of axonal degeneration requires TRPV1 expression. Local inflammation sensitized TRPV1 channels, which increased ocular pain. Thus, ocular TRPV1 overactivation drives DED-associated corneal nerve impairment.

Efficacy and safety of trigeminal parasympathetic pathway stimulation for dry eye: A systematic review and meta-analysis

This study aimed to investigate the efficacy and safety of trigeminal parasympathetic pathway (TPP) stimulation in the treatment of dry eye. A comprehensive search for randomized clinical trials was performed in seven databases (MEDLINE, Embase, CENTRAL, etc.) up to 28 February 2023. After screening the suitable studies, the data were extracted and transformed as necessary. Data synthesis and analysis were performed using Review Manager 5.4, and the risk of bias and quality of evidence were evaluated with the recommended tools. Fourteen studies enrolling 1714 patients with two methods (electrical and chemical) of TPP stimulation were included. Overall findings indicate that TPP stimulation was effective in reducing subjective symptom score (standardized mean difference [SMD], -0.45; 95% confidence interval [CI], -0.63 to -0.28), corneal fluorescence staining (mean difference [MD], -0.78; 95% CI, -1.39 to -0.18), goblet cell area (MD, -32.10; 95% CI, -54.58 to -9.62) and perimeter (MD, -5.90; 95% CI, -10.27 to -1.53), and increasing Schirmer's test score (SMD, 0.98; 95% CI, 0.65 to 1.31) and tear film break-up time (SMD, 0.57; 95% CI, 0.19 to 0.95). Compared to inactive or low-activity stimulation controls, it has a higher incidence of adverse events. Therefore, TPP stimulation may be an effective treatment for dry eye, whether electrical or chemical. Adverse events are relatively mild and tolerable. Due to the high heterogeneity and low level of evidence, the current conclusions require to be further verified.

A novel approach to the immediate effects of electroacupuncture on dry eye: A case series

INTRODUCTION

Dry eye disease (DED) is an inflammatory disorder that shares several features with autoimmune diseases. Research suggests that electroacupuncture (EA) is a promising alternative treatment option for this disorder; however, evidence of its immediate efficacy is limited.

CASE PRESENTATION

Three patients were diagnosed with DED, and used artificial tears or anti-inflammatory drugs for long-term relief of eye symptoms. However, the cure rates were low, and the side effects were high. To improve ocular symptoms, quality of life, and physical and mental health, the patients sought alternative complementary therapies and received electroacupuncture therapy. All patients showed significant improvements in fatigue and dryness of the ocular surface after 3-4 days of treatment, and follow-up after 4 weeks showed no tendency for recurrence. No adverse reactions or unexpected events were observed during treatment.

CONCLUSION

We propose an innovative electroacupuncture treatment aimed at fewer acupuncture points, shorter periods, and faster healing that improves the symptoms of patients with DED in the short term. Continuous current stimulation by anatomically positioned needles on both sides of the lacrimal gland and the creation of an electric field may improve the endogenous mechanisms of DED.

The Impact of Vaping on the Ocular Surface: A Systematic Review of the Literature

Background: The use of electronic cigarettes has become increasingly popular in recent years. However, the impact that electronic cigarettes have on the ocular surface is not well known. Therefore, the aim of this review is to explore the current literature on the acute and chronic sequelae of electronic cigarettes on the ocular surface. Methods: A systematic review of the literature was undertaken by keyword searching on the Embase, Medline, and Web of Science databases. Articles identified through the search underwent title/abstract screening, full-text screening, and data extraction. Results: A total of 18 studies were included in this review. Non-intended ocular surface exposures and intended exposures on the ocular surface were found to be associated with the use of electronic cigarettes. Conclusions: The impact of vaping on the ocular surface is not benign. There are significant risks that vaping can pose to the ocular surface. Hence, it is necessary to develop appropriate risk communication tools given the increasing popularity of this activity. Additionally, future long-term studies are needed to better understand the long-term impacts of vaping on the ocular surface given the lack of current data.

Discovery and Verification of Sjögren's Syndrome Protein Biomarkers in Tears by Targeted LC-MRM

Sjögren's syndrome (SS) is an autoimmune rheumatic disorder characterized by exocrine gland dysfunction, mainly from the lacrimal and salivary glands. The disease causes severe aqueous dry eye syndrome (DED) and is associated with high rates of complications, including corneal ulceration, scaring, and perforation. Systemic complications may occur as well as a higher risk of developing lymphoma. Diagnosis of SS-DED is often delayed and difficult to establish. With the aim of discovering biomarkers to help discriminate SS-DED patients, a combination of untargeted and targeted LC-MS/MS analyses were performed on tear samples collected on Schirmer strips and subjected to tryptic digestion. Following the analysis of three cohorts and the development of two targeted LC-sMRM methods for the verification of putative biomarkers found in the first cohort of samples, 64 proteins could be linked to Sjögren's syndrome, in the hopes of helping to confirm diagnoses as well as potentially stratifying the severity of disease in these patients. Proteins that were increased in SS-DED showed activation of the immune system and alterations in homeostasis. Several proteases and protease inhibitors were found to be significantly changing in SS-DED, as well as a consistent decrease in specific proteins known to be secreted by the lacrimal gland.

Prevalence of dry eye disease among IT students in Pakistan

BACKGROUND

Dry eye disease (DED) is a common tear film disorder caused by decreased tear production or increased tear evaporation. The increased use of computers in the workplace has brought about the development of ocular health concerns, including dry eye disease. Therefore, this study was designed to determine the prevalence of DED associated with computer work and recommend preventing or reducing its development. This study investigated the prevalence of DED among IT students in Dera Ghazi Khan.

METHODS

A cross-sectional descriptive study was conducted among 327 undergraduate students of the IT department in the district of Dera Ghazi khan over 5 months from September 2021 to January 2022. DED was assessed subjectively with Ocular Surface Disease Index. Data were analysed using SPSS version 21. The quantitative analysis was presented as mean and standard deviation, and qualitative variables were introduced in frequency and percentages. The chi-square test (Fisher's exact test) was used to study the significance of associations between dependent and independent variables.

RESULTS

The mean age of the participants was 20.25 ± 1.305 years (range 17-25). The prevalence of DED among computer programmers was 47.7%. This study showed that gender (p = 0.31), contact lens usage (p = 0.64), and duration of time spent on computer display units (p = 0.47) were not significant determinants of DED among computer programmers.

CONCLUSION

DED is prevalent among IT students, along with different symptoms. However, further studies are required to adequately measure the prevalence of DED during longer exposure time to computer screens and explore environmental risk factors.

Recent United States Developments in the Pharmacological Treatment of Dry Eye Disease

Dry eye disease (DED) can arise from a variety of factors, including inflammation, meibomian gland dysfunction (MGD), and neurosensory abnormalities. Individuals with DED may exhibit a range of clinical signs, including tear instability, reduced tear production, and epithelial disruption, that are driven by different pathophysiological contributors. Those affected often report a spectrum of pain and visual symptoms that can impact physical and mental aspects of health, placing an overall burden on an individual's well-being. This cumulative impact of DED on an individual's activities and on society underscores the importance of finding diverse and effective management strategies. Such management strategies necessitate an understanding of the underlying pathophysiological mechanisms that contribute to DED in the individual patient. Presently, the majority of approved therapies for DED address T cell-mediated inflammation, with their tolerability and effectiveness varying across different studies. However, there is an emergence of treatments that target additional aspects of the disease, including novel inflammatory pathways, abnormalities of the eyelid margin, and neuronal function. These developments may allow for a more nuanced and precise management strategy for DED. This review highlights the recent pharmacological advancements in DED therapy in the United States. It discusses the mechanisms of action of these new treatments, presents key findings from clinical trials, discusses their current stage of development, and explores their potential applicability to different sub-types of DED. By providing a comprehensive overview of products in development, this review aims to contribute valuable insights to the ongoing efforts in enhancing the therapeutic options available to individuals suffering from DED.

Anti-inflammatory effect of curcuminoids and their analogs in hyperosmotic human corneal limbus epithelial cells

BACKGROUND

To assess the efficacy of curcuminoids (curcumin, demethoxycurcumin, bisdemethoxycurcumin [BDC]) and their analogs (tetrahydrocurcumin [THC], tetrahydrodemethoxycurcumin [THDC], tetrahydrobisdemethoxycurcumin) in reducing inflammatory cytokines and their toxicity to primary human corneal limbal epithelial cells, these cells were cultured and exposed to these compounds.

METHODS

The PrestoBlue assay assessed cell viability after treatment. Anti-inflammatory effects on hyperosmotic cells were determined using real-time polymerase chain reaction and significance was gauged using one-way analysis of variance and Tukey's tests, considering p-values < 0.05 as significant.

RESULTS

Curcuminoids and their analogs, at 1, 10, and 100 µM, exhibited no effect on cell viability compared to controls. However, cyclosporin A 1:500 significantly reduced cell viability more than most curcuminoid treatments, except 100 µM curcumin and BDC. All tested curcuminoids and analogs at these concentrations significantly decreased mRNA expression levels of tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-17 A, matrix metallopeptidase-9, and intercellular adhesion molecule-1 after 90 mM NaCl stimulation compared to untreated cells. Furthermore, proinflammatory cytokine levels from hyperosmotic cells treated with 1, 10, and 100 µM curcumin, 100 µM BDC, 100 µM THC, 1 and 100 µM THDC mirrored those treated with cyclosporin A 1:500.

CONCLUSION

The anti-inflammatory efficiency of 1 and 10 µM curcumin, 100 µM THC, 1 and 100 µM THDC was comparable to that of cyclosporin A 1:500 while maintaining cell viability.

The Association between Ovarian Cancer and the Incidence of Newly Developed Dry Eye Disease: A Nationwide Population-Based Study

We aim to investigate the potential correlation between the presence of ovarian cancer and the development of dry eye disease (DED) via the usage of the Longitudinal Health Insurance Database (LHID) of Taiwan. A retrospective cohort study was executed, and patients with ovarian cancer were selected according to the diagnostic and procedure codes. One ovarian cancer patient was matched to four non-ovarian cancer participants which served as control group, and a total of 4992 and 19,968 patients constructed the ovarian cancer and control groups, respectively. The primary outcome in the current study is the development of DED according to the diagnostic and procedure codes. Cox proportional hazard regression was utilized to produce the adjusted hazard ratio (aHR) and related 95% confidence interval (CI) of DED between the two groups. There were 542 and 2502 DED events observed in the ovarian cancer group and the control group, respectively. The ovarian cancer group illustrated a significantly higher incidence of DED development than the control group after the adjustment of several confounders (aHR: 1.10, 95% CI: 1.01-1.21, p = 0.040). In the subgroup analysis stratified by age, ovarian cancer patients aged older than 60 years showed a higher incidence of DED compared to the non-ovarian cancer population (aHR: 1.19, 95% CI: 1.08-1.28, p = 0.011). In addition, ovarian cancer patients with a disease duration longer than five years also showed higher incidence of DED formation than the non-ovarian cancer population (aHR: 1.13, 95% CI: 1.04-1.22, p = 0.027). In conclusion, the presence of ovarian cancer is associated with higher incidence of subsequent DED, especially in those older than 60 years and with a disease interval of more than five years.

Recent Advances in Nanotechnology for the Treatment of Dry Eye Disease

Dry eye disease (DED) incidence is continuously growing, positioning it to become an emergent health issue over the next few years. Several topical treatments are commonly used to treat DED; however, reports indicate that only a minor proportion of drug bioavailability is achieved by the majority of eye drops available on the market. In this context, enhancing drug ability to overcome ocular barriers and prolonging its residence time on the ocular surface represent a new challenge in the field of ocular carrier systems. Therefore, research has focused on the development of multi-functional nanosystems, such as nanoemulsions, liposomes, dendrimers, hydrogels, and other nanosized carriers. These systems are designed to improve topical drug bioavailability and efficacy and, at the same time, require fewer daily administrations, with potentially reduced side effects. This review summarizes the different nanotechnologies developed, their role in DED, and the nanotechnology-based eyedrops currently approved for DED treatment.

Thermosensitive TRP Channels Are Functionally Expressed and Influence the Lipogenesis in Human Meibomian Gland Cells

While the involvement of thermosensitive transient receptor potential channels (TRPs) in dry eye disease (DED) has been known for years, their expression in the meibomian gland (MG) has never been investigated. This study aims to show their expression and involvement in the lipogenesis of the MG, providing a possible new drug target in the treatment of DED. Our RT-PCR, Western blot and immunofluorescence analysis showed the expression of TRPV1, TRPV3, TRPV4 and TRPM8 in the MG at the gene and the protein level. RT-PCR also showed gene expression of TRPV2 but not TRPA1. Calcium imaging and planar patch-clamping performed on an immortalized human meibomian gland epithelial cell line (hMGECs) demonstrated increasing whole-cell currents after the application of capsaicin (TRPV1) or icilin (TRPM8). Decreasing whole-cell currents could be registered after the application of AMG9810 (TRPV1) or AMTB (TRPM8). Oil red O staining on hMGECs showed an increase in lipid expression after TRPV1 activation and a decrease after TRPM8 activation. We conclude that thermo-TRPs are expressed at the gene and the protein level in MGs. Moreover, TRPV1 and TRPM8's functional expression and their contribution to their lipid expression could be demonstrated. Therefore, TRPs are potential drug targets and their clinical relevance in the therapy of meibomian gland dysfunction requires further investigation.

Ectoine protects corneal epithelial survival and barrier from hyperosmotic stress by promoting anti-inflammatory cytokine IL-37

PURPOSE

To explore novel role and molecular mechanism of a natural osmoprotectant ectoine in protecting corneal epithelial cell survival and barrier from hyperosmotic stress.

METHODS

Primary human corneal epithelial cells (HCECs) were established from donor limbus. The confluent cultures in isosmolar medium were switched to hyperosmotic media (400-500 mOsM), with or without ectoine or rhIL-37 for different time periods. Cell viability and proliferation were evaluated by MTT or WST assay. The integrity of barrier proteins and the expression of cytokines and cathepsin S were evaluated by RT-qPCR, ELISA, and immunostaining with confocal microscopy.

RESULTS

HCECs survived well in 450mOsM but partially damaged in 500mOsM medium. Ectoine well protected HCEC survival and proliferation at 500mOsM. The integrity of epithelial barrier was significantly disrupted in HCECs exposed to 450mOsM, as shown by 2D and 3D confocal immunofluorescent images of tight junction proteins ZO-1 and occludin. Ectoine at 5-20 mM well protected these barrier proteins under hyperosmotic stress. The expression of TNF-α, IL-1β, IL-6 and IL-8 were dramatically stimulated by hyperosmolarity but significantly suppressed by Ectoine at 5-40 mM. Cathepsin S, which was stimulated by hyperosmolarity, directly disrupted epithelial barrier. Interestingly, anti-inflammatory cytokine IL-37 was suppressed by hyperosmolarity, but restored by ectoine at mRNA and protein levels. Furthermore, rhIL-37 suppressed cathepsin S and rescued cell survival and barrier in HCECs exposed to hyperosmolarity.

CONCLUSION

Our findings demonstrate that ectoine protects HCEC survival and barrier from hyperosmotic stress by promoting IL-37. This provides new insight into pathogenesis and therapeutic potential for dry eye disease.

Therapeutic effect and mechanism of action of pterostilbene nano drugs in dry eye models

Dry eye disease is a multifactorial dysfunction of the tear film and ocular surface, with etiology involving inflammation and oxidative stress on the ocular surface. Pterostilbene (PS) is a secondary metabolite extracted from plants, which possesses remarkable anti-inflammatory and antioxidant effects. However, its application is limited by light instability and very poor water solubility. We modified fat-soluble PS into a biparental pterostilbene-glutaric anhydride-arginine-glycine-aspartic acid (PS-GA-RGD) nanomedicine by prodrug ligation of functional peptides. The aim of this study was to explore the protective effect and potential mechanism of PS-GA-RGD on dry eye disease in vitro and in vivo. We demonstrated good long-term biocompatibility of PS-GA-RGD through rabbit eye stimulation test. Lipopolysaccharide (LPS) was used to induce murine macrophages RAW 264.7 to establish an inflammation and oxidative stress model. In this model, PS-GA-RGD effectively reduced the production of ROS and 8-OHdG, enhancing the expression of antioxidant factor Nrf2 and antioxidant enzyme heme oxygenase-1. In addition, the expression of NF-κB inflammatory pathway significantly increased in LPS-induced RAW 264.7 cells, while PS-GA-RGD could significantly reduce this pathway. Hypertonic saline was utilized to establish a hypertonic model of human corneal epithelial cells. PS-GA-RGD was found to significantly reduce the production of ROS and NLRP3 inflammasomes in this model, exhibiting superior efficacy compared to PS. Experimental dry eye animal models were co-induced with subcutaneous injection of scopolamine and an intelligently controlled environmental system. We demonstrated that PS-GA-RGD nano drugs can prevent and reduce corneal epithelial cell defects and apoptosis, protect conjunctival goblet cells, and have an excellent anti-inflammatory effect. Finally, we demonstrated that RGD sequence in PS-GA-RGD can enhance cellular uptake, corneal retention, and penetration, thereby increasing their bioavailability and efficacy by a cell uptake assay and rabbit corneal drug retention experiment. Overall, this study highlights the potential of PS-GA-RGD nanomedicines in the treatment of dry eyes.

Efficacy of meibomian gland expression combined with Home-Based therapy in the management of dry eye Disease: A systematic review and Meta-Analysis

PURPOSE

To compare the effectiveness of meibomian gland expression (MGX) combined with home-based therapy versus home-based therapy alone for the treatment of dry eye disease (DED) caused by meibomian gland dysfunction (MGD).

METHODS

A systematic review of randomized controlled studies (RCTs), reporting the effects of MGX combined with home-based therapy in 2 databases, PubMed and Web of Science, was performed according to the PRISMA statement. The search period was until August 20, 2023. According to the heterogeneity, a random or fixed effects model was performed in the meta-analysis. The standardized mean difference (SMD) was calculated to analyze dry eye symptoms (DES) score, tear film break-up time (TBUT), total corneal fluorescein staining (tCFS) and meibomian glands expressibility (MGE). All analyses were performed by RevMan Web, version 5.7. The Cochrane risk of bias tool was used to analyze the quality of the studies selected.

RESULTS

Two RCTs with a total of 99 patients were included. The studies reported that MGX combined with home-based therapy improves DES score, TBUT, tCFS and MGE compared to the home-based therapy. However, the meta-analysis indicated that MGX combined with home-based therapy only seems to be beneficial in reducing DES score (SMD -0.49; 95 % CI: -0.89 to -0.08; P = 0.02; I2 = 0 %). In addition, although TBUT, tCFS and MGE reported a slight trend in favor of MGX combined with home-based therapy, it was non-significant.

CONCLUSIONS

While MGX combined with home-based therapy seem to show some evidence of alleviating dry eye symptoms, there is insufficient evidence to conclude the effects of this treatment definitively particularly in improving dry eye signs caused by MGD, such as TBUT, tCFS and MGE. Therefore, further RCTs are needed to elucidate these results.

Potential New Target for Dry Eye Disease-Oxidative Stress

Dry eye disease (DED) is a multifactorial condition affecting the ocular surface. It is characterized by loss of tear film homeostasis and accompanied by ocular symptoms that may potentially result in damage to the ocular surface and even vision loss. Unmodifiable risk factors for DED mainly include aging, hormonal changes, and lifestyle issues such as reduced sleep duration, increased screen exposure, smoking, and ethanol consumption. As its prevalence continues to rise, DED has garnered considerable attention, prompting the exploration of potential new therapeutic targets. Recent studies have found that when the production of ROS exceeds the capacity of the antioxidant defense system on the ocular surface, oxidative stress ensues, leading to cellular apoptosis and further oxidative damage. These events can exacerbate inflammation and cellular stress responses, further increasing ROS levels and promoting a vicious cycle of oxidative stress in DED. Therefore, given the central role of reactive oxygen species in the vicious cycle of inflammation in DED, strategies involving antioxidants have emerged as a novel approach for its treatment. This review aims to enhance our understanding of the intricate relationship between oxidative stress and DED, thereby providing directions to explore innovative therapeutic approaches for this complex ocular disorder.

Quantitative evaluation of morphological and functional changes in meibomian glands and lipid layer thickness in patients with and without keratoconus

PURPOSE

To quantitatively evaluate the morphological parameters of meibomian glands (MGs) and lipid layer thickness (LLT) in patients with keratoconus (KC).

METHODS

In this prospective, cross-sectional study, 164 eyes of 164 keratoconus patients and 64 eyes of 64 age-matched control subjects were included. An advanced automatic MG analyzer was used to quantitatively measure the morphological and functional parameters of MGs. Morphological and functional parameters of MGs, LLT, and other ocular surface parameters were compared between the control and KC groups.

RESULTS

The mean meibomian gland diameter, length, square, and gland area ratio (GA) were all significantly decreased in the KC group (all P < 0.05), while no significant difference was observed in the gland tortuosity index (TI) and gland signal index (SI) between the KC and control groups (all P > 0.05). There was no significant difference in the number of total and incomplete blinking among patients with different stages of keratoconus (all P > 0.05). The gland diameter, square, and TI were all negatively associated with KC severity (all P < 0.05), while no significant difference was observed among all stages of KC in gland length, GA, and SI (all P > 0.05). Moreover, the LLTs were positively correlated with the gland diameter, square, GA, and TI and negatively correlated with anterior corneal curvature or KC severity (all P < 0.05).

CONCLUSIONS

Atrophic morphological changes in the meibomian glands were closely correlated with the severity of keratoconus. Gland diameter may be a sensitive functional morphology metric of meibomian glands in patients with keratoconus.

Deep learning-based fully automated grading system for dry eye disease severity

There is an increasing need for an objective grading system to evaluate the severity of dry eye disease (DED). In this study, a fully automated deep learning-based system for the assessment of DED severity was developed. Corneal fluorescein staining (CFS) images of DED patients from one hospital for system development (n = 1400) and from another hospital for external validation (n = 94) were collected. Three experts graded the CFS images using NEI scale, and the median value was used as ground truth. The system was developed in three steps: (1) corneal segmentation, (2) CFS candidate region classification, and (3) estimation of NEI grades by CFS density map generation. Also, two images taken on different days in 50 eyes (100 images) were compared to evaluate the probability of improvement or deterioration. The Dice coefficient of the segmentation model was 0.962. The correlation between the system and the ground truth data was 0.868 (p<0.001) and 0.863 (p<0.001) for the internal and external validation datasets, respectively. The agreement rate for improvement or deterioration was 88% (44/50). The fully automated deep learning-based grading system for DED severity can evaluate the CFS score with high accuracy and thus may have potential for clinical application.

Impact of Clinician Subjectivity on the Assessment of Dry Eye Disease Prevalence in a UK Public Health Care Patient Population

Purpose

To understand the impact of subjectivity on diagnosis rates of dry eye disease (DED) in an unbiased population.

Patients and Methods

A multicenter study enrolled 818 subjects with complete report forms (465 females, 67.1 ± 16.7 years, 353 males, 65.0 ± 15.9 years). Subjects were evaluated for staining, TBUT, tear osmolarity, meibomian gland disease, and OSDI.

Results

Physicians diagnosed 48.7% of subjects as having DED, ranging from 42.9% to 62.3% between sites. Positivity rates for staining (≥ grade 1) ranged from 41.3% to 84.1% (mean = 0.8 ± 0.9 grade), TBUT (<10s) ranged from 39.1% to 61.6% (mean = 10.4 ± 6.6 seconds), osmolarity (>308 mOsm/L) ranged from 63.7% to 72.4% (mean = 319.7 ± 20.8), MGD grading ranged from 28.9% to 51.3% (mean = 0.5 ± 0.7), and symptoms measured by OSDI ranged from 57.6% to 71.0% (mean = 23.5 ± 20.5) between sites. Tear osmolarity was the most consistent between sites (max/min positivity = 114%), followed by OSDI (123%), TBUT (158%), MGD (178%), and staining (204%). DED markers were uncorrelated (average r2 = 0.05 ± 0.07). A substantial number of subjects (N = 110) exhibited positive symptoms (OSDI = 32.4 ± 15.7) and hyperosmolarity (338.1 ± 20.1 mOsm/L) but no other obvious signs of DED (MGD grade = 0.2 ± 0.4, TBUT = 13.5 ± 7.0 seconds, staining grade = 0.4 ± 0.5).

Conclusion

Subjective signs of DED varied considerably, whereas objective measurements of OSDI and osmolarity were the most consistent between sites. A large proportion of subjects exhibited high symptoms and hyperosmolarity but no other obvious signs of dry eye disease, most of whom were undiagnosed by clinical assessment without access to the osmolarity measurement.

How gut microbiota may impact ocular surface homeostasis and related disorders

Changes in the bacterial flora in the gut, also described as gut microbiota, are readily acknowledged to be associated with several systemic diseases, especially those with an inflammatory, neuronal, psychological or hormonal factor involved in the pathogenesis and/or the perception of the disease. Maintaining ocular surface homeostasis is also based on all these four factors, and there is accumulating evidence in the literature on the relationship between gut microbiota and ocular surface diseases. The mechanisms involved are mostly interconnected due to the interaction of central and peripheral neuronal networks, inflammatory effectors and the hormonal system. A better understanding of the influence of the gut microbiota on the maintenance of ocular surface homeostasis, and on the onset or persistence of ocular surface disorders could bring new insights and help elucidate the epidemiology and pathology of ocular surface dynamics in health and disease. Revealing the exact nature of these associations could be of paramount importance for developing a holistic approach using highly promising new therapeutic strategies targeting ocular surface diseases.

Sialylated IVIg promotes clinical improvements in a rabbit dry eye model by regulating inflammatory cytokines

Dry eye disease (DED) is caused by a loss of homeostasis of the tear film, which results in visual disturbance, ocular surface inflammation and damage, and neurosensory abnormalities. Although it is prevalent in 5-50% of the global population, there are limited clinical options for its treatment. This study explored the potential use of human intravenous immunoglobulin (IVIg) and its enriched fractions of sialylation, sialylated IVIg (sIVIg), as a treatment for DED. Fifteen female New Zealand white rabbits were topically instilled with 0.2% benzalkonium chloride (BAC) twice daily for five consecutive days to induce experimental dry eye. Saline, 0.4% IVIg, or 0.04% sIVIg eye drops were instilled twice daily for 20 consecutive days. Clinical evaluations, such as non-invasive tear break-up time (NIBUT) and corneal fluorescein staining (CFS), were conducted. mRNA levels of mucin 4, mucin 16, TNF-α, IL-1β, MMP9, IL-10, TGF-β, and CD209 in rabbit conjunctival tissues were examined using reverse transcription polymerase chain reaction (RT-PCR) or quantitative RT-PCR (qRT-PCR). The relationships between CD209 family members in rabbits and various mammalian species were analyzed using a phylogenetic tree. IVIg or sIVIg treatment resulted in clinical improvements in the rabbit DED model. The inflammatory cytokines, TNF-α and IL-1β, were increased and mucin 4 and mucin 16, cell surface-associated mucins, were decreased in BAC-induced dry eye. Following IVIg or sIVIg treatment, inflammatory cytokines decreased, whereas the anti-inflammatory cytokine, IL-10, increased substantially. Moreover, a 10-fold lower sIVIg treatment dose resulted in prolonged IL-10 production, representing a significantly improved DED compared to IVIg. Furthermore, the expression of rabbit CD209 mRNA in the rabbit conjunctiva and its close relationship with primate homologs suggest that it may interact with IVIg or sIVIg to promote IL-10 expression, as previously described in humans. At a lower dosage, sIVIg showed a more efficient improvement in DED, making it a promising new candidate medication for DED.

A Novel Ophthalmic Solution Containing Glicopro® Complex for the Treatment of Patients with Dry Eye Disease: Results from a Pilot Study

(1) Background: Dry eye disease (DED) is a multifactorial ocular surface disease characterized by an imbalance in ocular surface homeostasis, and tear substitutes constitute the first line of treatment. The present study aimed to evaluate the changes in the signs and symptoms of patients with DED treated with a novel tear substitute containing the GlicoPro® complex. (2) Methods: Patients with DED not successfully responding to other tear substitutes were enrolled and treated with a novel ophthalmic solution (two drops four times daily). Patients were examined before starting the study treatment (T0) and after 30 (T1) and 60 (T2) days of treatment by means of Keratograph for the evaluation of the following: (i) tear meniscus height (TMH); (ii) noninvasive Keratograph break-up time (NIKBUT); (iii) bulbar redness; and (iv) infrared meibography. The SANDE questionnaire was administered to assess ocular discomfort symptoms. Analysis of the tear content of proenkephalin and Met/Leu-enkephalin was also performed. (3) Results: At T2, a significant improvement in NIKBUT first, average, and class, TMH, and SANDE score was found. The tear content of proenkephalins was significantly higher at T1, whereas processed active Met/Leu-enkephalins increased at both T1 and T2. (4) Conclusions: Our novel tear substitute based on GlicoPro® resulted in a significant improvement in ocular discomfort symptoms, tear volume, and stability in the patients treated. The increase in active peptides processed in tears may represent the pathophysiological substrate underlying this finding.

Modified Danzhi Xiaoyao Powder (MDXP) improves the corneal damage in dry eye disease (DED) mice through phagocytosis

ETHNOPHARMACOLOGICAL RELEVANCE

Modified Danzhi Xiaoyao Powder (MDXP) is a traditional Chinese medicine formula remedy for treating Dry Eye Disease (DED). It showed the function of dispersing stagnated liver Qi for relieving Qi stagnation and clearing heat, which can be effective in treating conditions such as Dry Eye Disease (DED) and irregular menstruation due to liver depression and fire transformation.

AIM OF THE STUDY

This study investigated the mechanism of the effect of MDXP in mice with DED.

MATERIALS AND METHODS

A DED model was induced in mice using chronic painful stimulation (tail clamping) in combination with Benzalkonium Chloride Solution drops administered in a dry box for 28 days. After modeling, the MDXP groups were given Chinese medicine with different dosages by gavage for 14 days. The following parameters were recorded in each group: body mass, anal temperature, tear secretion, tear film rupture time, and corneal fluorescein staining. Behavioral changes were evaluated by elevating cross-maze and open-field experiments. The levels of inflammatory factors serum tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), fcγR-mediated phagocytosis pathway cell division control protein 42 homolog (CDC42), actin-related protein 2/3 complex subunit 2 (ARPC2), and actin-related protein 3 (ACTR3) were measured by using Enzyme-linked immunoassay (ELISA), immunohistochemical staining, and real-time fluorescent qualitative polymerase chain reaction (RT-qPCR).

RESULTS

MDXP increased body mass and lowered body temperature, prolonged tear film break-up time, promoted tear secretion, repaired corneal damage, decreased horizontal and vertical scores, elevated percentage of open arm times and boom opening time percentage, and reduced the expression levels of inflammatory factors of TNF-α, IL-1β and pathway-related proteins CDC42, ARPC2, and ACTR3 in mice. MDXP also reduced the expression levels of inflammatory factors of TNF-α and IL-1β in human corneal endothelial cells (HCECs), mouse mononuclear macrophage cells (RAW264.7), and human myeloid leukemia mononuclear cells (THP-1).

CONCLUSIONS

MDXP can relieve tension and anxiety, inhibit apoptosis, reduce phagocytosis, reduce the expression of pro-inflammatory factors, repair corneal damage, and improve the symptoms in DED mice. The mechanism of action may be through the fcγR-mediated phagocytosis pathway.

Adult stem cells in the eye: Identification, characterisation, and therapeutic application in ocular regeneration - A review

Adult stem cells, present in various parts of the human body, are undifferentiated cells that can proliferate and differentiate to replace dying cells within tissues. Stem cells have specifically been identified in the cornea, trabecular meshwork, crystalline lens, iris, ciliary body, retina, choroid, sclera, conjunctiva, eyelid, lacrimal gland, and orbital fat. The identification of ocular stem cells broadens the potential therapeutic strategies for untreatable eye diseases. Currently, stem cell transplantation for corneal and conjunctival diseases remains the most common stem cell-based therapy in ocular clinical management. Lens epithelial stem cells have been applied in the treatment of paediatric cataracts. Several early-phase clinical trials for corneal and retinal regeneration using ocular stem cells are also underway. Extensive preclinical studies using ocular stem cells have been conducted, showing encouraging outcomes. Ocular stem cells currently demonstrate great promise in potential treatments of eye diseases. In this review, we focus on the identification, characterisation, and therapeutic application of adult stem cells in the eye.

Understanding CFTR Functionality: A Comprehensive Review of Tests and Modulator Therapy in Cystic Fibrosis

Cystic fibrosis is a genetic disorder inherited in an autosomal recessive manner. It is caused by a mutation in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene on chromosome 7, which leads to abnormal regulation of chloride and bicarbonate ions in cells that line organs like the lungs and pancreas. The CFTR protein plays a crucial role in regulating chloride ion flow, and its absence or malfunction causes the production of thick mucus that affects several organs. There are more than 2000 identified mutations that are classified into seven categories based on their dysfunction mechanisms. In this article, we have conducted a thorough examination and consolidation of the diverse array of tests essential for the quantification of CFTR functionality. Furthermore, we have engaged in a comprehensive discourse regarding the recent advancements in CFTR modulator therapy, a pivotal approach utilized for the management of cystic fibrosis, alongside its concomitant relevance in evaluating CFTR functionality.

Meibomian Gland Probing Stimulates a Proliferative Epithelial Response Resulting in Duct Regeneration

Purpose

To demonstrate that the meibomian gland ductal basement membrane and basal epithelial cell layer are in continuity with and may derive from lid margin orifice-associated rete ridge epithelial/basement membrane structures (OARREBS) and to characterize changes in the distal duct microanatomy after meibomian gland probing (MGP) using in vivo confocal microscopy (IVCM).

Patients and Methods

Pre/post-MGP IVCM examinations were performed on upper lids. Thirty-six identical glands from 20 lids of 16 patients (49.24 ±17.11 y/o with 13:3 F:M) were identified, analyzed, and compared to control cases. Statistical analyses were performed using ImageJ software and IBM SPSS version 27. All MGPs were performed within 12 weeks of the initial examination. Post-MGP follow-up exams occurred at 5.03 ±4.48 months.

Results

Post-MGP images showed more superficially organized OARREBS with accelerated and more superficial basement membrane formation, and an average increase of 32.2%, 25.4%, 32.04%, 77.7%, and 81.3% in duct wall epithelial cell layers (DWECL) (p < 0.001, compared to control (CTC) p < 0.001), distal duct wall thickness (DWT) (p < 0.001, CTC p < 0.001), proximal DWT (p < 0.001, CTC p < 0.001), distal lumen area (p < 0.001, CTC p = 0.037), and proximal lumen area (p < 0.001, CTC p = 0.007), respectively. The increase in the distal DWT and lumen area correlated with the months of follow-up (p = 0.004 and p = 0.010, respectively). Immediate post-MGP imaging revealed the probe track confined to the ductal epithelial compartment.

Conclusion

MGP appears to stimulate a proliferative epithelial response characterized by an accelerated more superficial formation of ductal basement membrane with increased DWECL as well as DWT and lumen area at two separate duct foci. These findings suggest activation of lid margin meibomian gland precursor cells and confirm that MGP stimulates an epithelial regenerative phenomenon, not a fibrotic one.