Elevated Aqueous Cytokine Levels in Eyes With Ocular Surface Diseases

Development of topical eye-drops of lactoferrin-loaded biodegradable nanoparticles for the treatment of anterior segment inflammatory processes

Ocular inflammation is one of the most common comorbidities associated to ophthalmic surgeries and disorders. Since conventional topical ophthalmic treatments present disadvantages such as low bioavailability and relevant side effects, natural alternatives constitute an unmet medical need. In this sense, lactoferrin, a high molecular weight protein, is a promising alternative against inflammation. However, lactoferrin aqueous instability and high nasolacrimal duct drainage compromises its potential effectiveness. Moreover, nanotechnology has led to an improvement in the administration of active compounds with compromised biopharmaceutical profiles. Here, we incorporate lactoferrin into biodegradable polymeric nanoparticles and optimized the formulation using the design of experiments approach. A monodisperse nanoparticles population was obtained with an average size around 130 nm and positive surface charge. Pharmacokinetic and pharmacodynamic behaviour were improved by the nanoparticles showing a prolonged lactoferrin release profile. Lactoferrin nanoparticles were non-cytotoxic and non-irritant neither in vitro nor in vivo. Moreover, nanoparticles exhibited significantly increased anti-inflammatory efficacy in cell culture and preclinical assays. In conclusion, lactoferrin loaded nanoparticles constitute a safe and novel nanotechnological tool suitable for the treatment of ocular inflammation.

Ocular mucous membrane pemphigoid: novel treatment strategies

PURPOSE OF REVIEW

To describe current treatments of ocular mucous membrane pemphigoid (OMMP), including conventional systemic immunosuppression (CIST) and novel biologic agents.

RECENT FINDINGS

CIST remains the main stay therapy for the management of OMMP. The choice of agents is tailored to disease severity - mild disease is treated with dapsone, whereas moderately severe cases are often treated with mycophenolate mofetil or sulfa-based drugs and severe cases are treated with cyclophosphamide. In recalcitrant disease newer biologics such as Rituximab, intravenous immunoglobins and tumour necrosis alpha antagonists have proven to be effective in disease control. Control of inflammation with topical therapy and halting conjunctival fibrosis remain as areas of unmet clinical needs.

SUMMARY

OMMP is largely treated with CIST. The recent introduction of new biologic agents could shape the way the disease is treated in the near future.

Tear Film Cytokine Profile of Patients With the Boston Keratoprosthesis Type 1: Comparing Patients With and Without Glaucoma

Purpose

Inflammatory cytokines are involved in glaucoma pathogenesis. The purpose is to compare cytokine levels in the tear film of Boston keratoprosthesis (KPro) patients with and without glaucoma, relative to controls, and correlate levels with clinical parameters.

Methods

This cross-sectional study enrolled 58 eyes (58 patients): 41 KPro eyes with glaucoma, 7 KPro eyes without glaucoma, and 10 healthy controls. Twenty-seven cytokines were measured by multiplex bead immunoassay. Intraocular pressure (IOP), cup-to-disk ratio (CDR), retinal nerve fiber layer, visual acuity, topical medications, and angle closure were assessed in all KPro eyes. Cytokine levels between groups were analyzed by nonparametric tests, and correlations with clinical parameters by Spearman's test.

Results

Levels of TNF-ɑ, IL-1β, FGF-basic, and IFN-ɣ were significantly higher in KPro with glaucoma compared to KPro without (P = 0.020; 0.008; 0.043; 0.018, respectively). KPro groups had similar characteristics and topical antibiotic/steroid regimen. Levels of IL-1Ra, IL-15, VEGF, and RANTES were significantly higher in KPro with glaucoma compared to controls (P < 0.001; = 0.034; < 0.001; = 0.001, respectively). IL-1β and IFN-ɣ levels were positively correlated with CDR (r = 0.309, P = 0.039 and r = 0.452, P = 0.006, respectively) and IOP (r = 0.292, P = 0.047 and r = 0.368, P = 0.023, respectively). TNF-α and FGF-basic levels were positively correlated with CDR (r = 0.348, P = 0.022 and r = 0.344, P = 0.021, respectively).

Conclusions

TNF-α, IL-1β, FGF-basic, IFN-ɣ are elevated in tears of KPro patients with glaucoma and correlate with CDR and IOP. These results show, for the first time in humans, concordance with documented elevations of TNF-α and IL-1β in the murine KPro model. Ocular surface inflammation may reflect inflammatory processes of KPro glaucoma.

Two case reports of continued progression of chronic ocular graft-versus-host disease without concurrent systemic comorbidities treated by amniotic membrane transplantation

Background

Chronic ocular graft-versus-host disease (oGVHD) is an ocular comorbidity of graft-versus-host disease (GVHD) that usually occurs concurrently with systemic manifestations. Failure to detect and treat oGVHD in its early stages may lead to progression of ocular signs and symptoms leading to oGVHD that is refractory to conventional treatment.

Case presentation

We report the clinical course of a 19-year-old male and a 59-year-old female with severe and progressive chronic oGVHD without concurrent systemic signs of chronic graft-versus-host disease (cGVHD). Although their systemic conditions had been stable, both suffered from severe oGVHD and were referred to our clinic. Both cases exhibited marked improvement in conjunctival inflammation and fibrotic changes after amniotic membrane transplantation (AMT). Both cases underwent keratoplasty eventually to stabilize ocular surface conditions and to improve visual function.

Conclusions

We reported the clinical outcomes of 2 cases of chronic oGVHD without concurrent systemic comorbidities that were treated with AMT. The clinician should be aware that cGVHD may persist in target organs even in the absence of concurrent systemic comorbidities following seemingly successful systemic treatment. A multidisciplinary team approach is essential in the early detection and therapeutic intervention for chronic oGVHD.

CircRNA expression profile and functional analysis in retinal ischemia-reperfusion injury

Retinal ischemia-reperfusion (I/R) is involved in the pathogenesis of many vision-threatening diseases. circRNAs act as key players in gene regulation and human diseases. However, the global circRNA expression profile in retinal I/R injury has not been fully uncovered. Herein, we established a murine model of retinal I/R injury and performed circRNA microarrays to identify I/R-related circRNAs. 1265 differentially expressed circRNAs were identified between I/R retinas and normal retinas. Notably, the detection of cWDR37 level in aqueous humor could discriminate glaucoma patients from cataract patients (AUC = 0.9367). cWdr37 silencing protected against hypoxic stress- or oxidative stress-induced retinal ganglion cell (RGC) injury. cWdr37 silencing alleviated IR-induced retinal neurodegeneration as shown by increased NeuN staining, reduced retinal reactive gliosis, and decreased retinal apoptosis. Collectively, this study provides a novel insight into the pathogenesis of retinal I/R injury. cWdr37 is a promising target for the diagnosis or treatment of I/R-related ocular diseases.

Disruption of blood-aqueous barrier in dry eye disease

PURPOSE

To evaluate level of flare in aqueous humor of dry eye disease (DED) and compare it with normal controls.

METHODS

In this cross-sectional study, we compared the anterior chamber flare between 28 patients with DED (the DED group) and 27 normal age- and gender-matched controls (the control group). DED group was divided in Sjӧgren's syndrome dry eye (SDE, n = 10) and non- Sjӧgren's syndrome dry eye (non-SDE, n = 18) groups.

RESULTS

This study enrolled 55 participants including 28 patients with DED and 27 normal controls. The mean age was 53.4 ± 14.7 years in the DED group and 48.5 ± 14.7 years in the control group (P = 0.086). Mean flare was significantly higher in DED group (12.1 ± 10.2 ph/ms, range 2.7-68.3) compared to the control group (5.0 ± 3.9 ph/ms, range 1.30-30.0, P < 0.001). There was no statistically significant difference in the flare intensity between the Sjӧgren syndrome dry eye (SDE) group (14.5 ± 14.4 ph/ms) and the non-Sjӧgren dry eye (non-SDE) group (10.8 ± 6.9 ph/ms, P = 0.330). A significant correlation was observed between the flare intensity and the ocular surface staining in the SDE group (r = 0.62, P = 0.018).

CONCLUSION

There is a significant increase in aqueous humor flare in patients with DED. Such finding, which is a marker of disruption of blood-aqueous barrier, demonstrates deeper tissue involvement than ocular surface in these patients.

The role of IL-6-174 G/C polymorphism and intraocular IL-6 levels in the pathogenesis of ocular diseases: a systematic review and meta-analysis

Interleukin-6 (IL-6) is one of the key regulators behind the inflammatory and pathological process associated with ophthalmic diseases. The role of IL-6-174 G/C polymorphism as well as intraocular IL-6 levels among various eye disease patients differ across studies and has not been systematically reviewed. Thus, this study aims to provide a summary to understand the relationship between IL-6 and ophthalmic disease. In total, 8,252 and 11,014 subjects for IL-6-174 G/C and intraocular levels of IL-6, respectively, were retrieved from PubMed, Scopus and Web of Science. No association was found between IL-6-174 G/C polymorphisms with ocular diseases. Subgroup analyses revealed a suggestive association between the GC genotype of IL-6-174 G/C with proliferative diabetic retinopathy (PDR). Further, the level of intraocular IL-6 among ocular disease patients in general was found to be higher than the control group [standardized mean difference (SMD) = 1.41, 95% confidence interval (CI) 1.24-1.58, P < 0.00001]. Closer examination through subgroup analyses yielded similar results in several ocular diseases. This study thus indicates that the IL-6-174 G/C polymorphism does not predispose patients to ocular disease, although the GC genotype is likely to be a genetic biomarker for PDR. Moreover, intraocular IL-6 concentrations are related to the specific manifestations of the ophthalmic diseases. Further studies with larger sample sizes are warranted to confirm this conclusion.

Correlations between tear fluid and aqueous humor cytokine levels in bullous keratopathy

PURPOSE

To evaluate the correlation between tear fluid and aqueous humor (AqH) cytokine levels in eyes with bullous keratopathy (BK) and with normal endothelium.

METHODS

This prospective consecutive case-series study included 71 eyes of 71 patients: 31 eyes with BK, 18 eyes with non-BK corneal diseases, and 22 eyes with uncomplicated cataract (healthy controls). Total protein and cytokine (interleukin [IL]-1α, IL-1β, IL-4, IL-6, IL-8, IL-10, MIP-1α, MIP-1β, monocyte chemotactic protein [MCP]-1, E-selectin, P-selectin, soluble intercellular adhesion molecule [sICAM]-1, and IP-10) levels in the tear fluid and AqH were measured using multiplex beads immunoassay. The correlations between tear and AqH cytokine levels were assessed.

RESULTS

The AqH protein level was significantly higher in BK eyes (1.09 ± 0.08 mg/mL) than in non-BK (0.63 ± 0.11, P = 0.0004) and healthy control (0.62 ± 0.06, P = 0.0002) eyes. The tear total protein and IL-4 levels were significantly higher in the BK group compared to healthy controls (P = 0.0374 and 0.0032, respectively). The AqH IL-8 and sICAM-1 levels were significantly higher in the BK group compared to controls (P = 0.0001 and 0.0083, respectively). In BK eyes, the tear IL-4 level was significantly correlated with the MCP-1(r = 0.563, P = 0.001) and total protein (r = 0.589, P = 0.001) AqH levels. The tear IL-8 level was significantly correlated with the MCP-1(r = 0.598, p = 0.001) and IL-4 (r = 0.781, p < 0.0001) AqH levels in BK eyes. However, no significant correlations were found between tear and AqH cytokine levels in non-BK and healthy controls eyes.

CONCLUSIONS

The tear cytokine levels are correlated with those of AqH only in BK, but not in non-BK and healthy controls.

The Differential Expression of Cytokines and Growth Factors After SMILE Compared With FS-LASIK in Rabbits

Purpose

To investigate the differential expression of cytokines and growth factors in the cornea and aqueous humor after small incision lenticule extraction (SMILE) compared with femtosecond LASIK (FS-LASIK) using rabbit model.

Methods

Sixteen eyes of 16 rabbits in each group underwent SMILE or FS-LASIK with refractive correction of −6.00 DS/−1.00 DC. Eight additional rabbits served as controls. Pre- and 24 hours, 1 week, 1 month, and 3 months postoperatively, slit-lamp and anterior segment optical coherence tomography were performed, followed by cornea and aqueous humor collection. Apoptosis and proliferation were evaluated with TUNEL assay and Ki-67 immunostaining, respectively. The mRNA and protein expression of cytokines and growth factors was determined by RT-qPCR and Western blotting, respectively. Cytokine levels in the aqueous humor were detected with ELISA.

Results

Compared with FS-LASIK, SMILE induced less apoptosis and proliferation in the cornea within 1 week postoperatively. Levels of IL-1β, TNF-α, and EGFR in the cornea were significantly increased after FS-LASIK compared with SMILE within 24 hours. Levels of IL-8 in the aqueous humor remained elevated until 1 week after FS-LASIK but not SMILE. TGF-β1 level was elevated up to 1 month after both procedures, while BFGF level was kept high within 1 month after SMILE but not FS-LASIK.

Conclusions

SMILE could induce significantly less acute inflammation than FS-LASIK in the cornea and aqueous humor. The differential expression of TGF-β1 and BFGF between two procedures until 1 month might contribute to the post-SMILE delayed recovery and underline the importance of continued treatment postoperatively.

Ultraviolet Radiation Exposure of One Eye Stimulates Sympathizing Expression of Neurokinin-1 Receptor but Not Monocyte Chemoattractant Protein-1 in the Partner Eye

PURPOSE

To investigate the influence of unilateral ultraviolet radiation (UVR) exposure on the unexposed, partner eye in vivo. To characterize the immunological cross-talk between the eyes and verify a sympathizing reaction of the partner eye via a neurokinin-dependent signaling pathway of substance P and its neurokinin-1 receptor (NKR-1) and/or monocyte chemoattractant protein-1 (MCP-1).

METHODS

C57BL/6 mice were unilaterally exposed in vivo to UVR-B to a 5-fold cataract threshold equivalent dose of 14.5 kJ/m2 with a UV irradiation Bio-Spectra system. The unexposed contralateral eye was completely shielded during irradiation. After 3 and 7 days post exposure, eyes were stained with fluorescence-coupled antibody for substance P NKR-1. The same was performed in control animals receiving only anesthesia but no UVR-B exposure. NKR-1 and MCP-1 levels in ocular tissue lysates were quantified by enzyme-linked immunosorbent assay.

RESULTS

UVR-B induces NKR-1 upregulation after 3 and 7 days in the exposed and in the unexposed, contralateral mouse eye. NKR-1 protein level was upregulated in the exposed and contralateral iris/ciliary body complex, choroidea and in the contralateral retina as well as in the exposed cornea. MCP-1 levels were elevated in the exposed cornea, iris/ciliary body complex, and aqueous humor but not in contralateral ocular tissues.

CONCLUSIONS

UVR-B exposure triggers NKR-1 upregulation not only in the exposed but also in the unexposed, partner eye in various ocular tissues. Following UVR-B exposure, MCP-1 protein levels are upregulated in the exposed eye, but the contralateral side remains unaffected.

Inflammatory Response in Dry Eye

Purpose

Dry eye is a major ocular pathology worldwide. Although dry eye is a multifactorial disease, recent studies have shown that chronic immunologic processes have a pivotal role in its pathogenesis, characterized by the infiltration of immune cells in the lacrimal glands, elevated levels of tear inflammatory cytokines, and increased density of immune cells in the cornea and conjunctiva. This review describes the recent advances in understanding the relationship between dry eye and inflammation.

Methods

This narrative review is based on searches of recent international literature using terms related to the immune response in dry eye, and includes clinical trials, animal experiments, and expert reviews.

Results

Although dry eye presents clinically as tear film instability associated with corneal/conjunctival epithelial disorders, Meibomian gland dysfunction, and decreased visual function, recent laboratory and clinical studies have indicated inflammation in the lacrimal glands, Meibomian glands, conjunctiva, cornea, and aqueous tears. Furthermore, inflammation at these locations leads to conjunctival goblet cell apoptosis, corneal epithelial barrier disruption, and corneal nerve damage. These inflammatory outcomes can be exacerbated by intrinsic and extrinsic factors, such as aging, sex steroid hormone, autoimmune diseases, contact lens use, visual display terminals, and dry environment.

Conclusions

Recent advances in dry eye research have revealed the inflammatory process and its pathogenesis, which has been proposed as an "inflammatory vicious cycle" of dry eye. Comprehensive assessment of dry eye based on inflammation will improve the selection of treatments and help break the inflammatory cycle in clinical settings.

Immune privilege in corneal transplantation

Corneal transplantation is the most successful solid organ transplantation performed in humans. The extraordinary success of orthotopic corneal allografts, in both humans and experimental animals, is related to the phenomenon of "immune privilege". Inflammation is self-regulated to preserve ocular functions because the eye has immune privilege. At present, three major mechanisms are considered to provide immune privilege in corneal transplantation: 1) anatomical, cellular, and molecular barriers in the cornea; 2) tolerance related to anterior chamber-associated immune deviation and regulatory T cells; and 3) an immunosuppressive intraocular microenvironment. This review describes the mechanisms of immune privilege that have been elucidated from animal models of ocular inflammation, especially those involving corneal transplantation, and its relevance for the clinic. An update on molecular, cellular, and neural interactions in local and systemic immune regulation is provided. Therapeutic strategies for restoring immune privilege are also discussed.

Association of Iris Damage With Reduction in Corneal Endothelial Cell Density After Penetrating Keratoplasty

PURPOSE

To evaluate the effect of iris damage on endothelial cell loss in the early phase after penetrating keratoplasty (PKP).

METHODS

This prospective consecutive study included 74 patients who underwent PKP without graft rejection during the follow-up period. Endothelial cell density (ECD) was measured using specular microscopy at 1, 3, 6, and 12 months after PKP. Iris damage scores (IDSs) were determined on the basis of slit-lamp microscopy or anterior segment optical coherence tomography imaging. Graft survival rates were compared among the different IDSs. Using multivariate analysis, the factors influencing postoperative ECD were assessed, taking into consideration the presence of glaucoma, history of graft failure, donor age, and graft ECD as independent variables.

RESULTS

Graft ECD decreased from 2674 ± 329 cells/mm to 2114 ± 570 at 1 month, 1907 ± 629 at 3 months, 1669 ± 738 at 6 months, and 1404 ± 792 at 12 months (all, P < 0.0001). ECD at 12 months was associated with the IDS (β = -0.444, P < 0.0001), graft ECD (β = 0.309, P = 0.003), and history of graft failure (β = -0.251, P = 0.016). The IDS was significantly correlated with %ECD loss at 1 month (r = 0.427, P = 0.003), at 3 months (r = 0.376, P = 0.002), at 6 months (r = 0.301, P = 0.013), and at 12 months (r = 0.517, P < 0.0001). The graft survival rates in eyes with severe iris damage were significantly lower than those in eyes with either no or mild iris damage (P < 0.0001).

CONCLUSIONS

Severe iris damage is associated with rapid reduction in ECD and graft endothelial failure after PKP.

Cytokine Levels in the Aqueous Humor Are Associated With Corneal Thickness in Eyes With Bullous Keratopathy

PURPOSE

We sought to investigate the association between the severity of bullous keratopathy and proinflammatory cytokine levels in the aqueous humor (AqH).

DESIGN

Cross-sectional study.

METHODS

This study included a total of 95 eyes: 62 with bullous keratopathy and 33 that underwent cataract surgery. Central corneal thickness (CCT) and central corneal volume within 4 and 6 mm (CCV_4mm and CCV_6mm, respectively) were determined using anterior segment optical coherence tomography. A total of 95 AqH samples were collected at the beginning of surgery. The levels of cytokines (interleukins [ILs]-1α, -1β, -4, -6, -8, -10, -12p70, -13, -17A, interferon [IFN]-α, IFN-γ, monocyte chemotactic protein [MCP]-1, E-selectin, P-selectin, and soluble intercellular adhesion molecule-1 [sICAM-1]) in the AqH were measured using multiplex beads immunoassay. We evaluated the correlation among AqH cytokine levels, CCT, CCV_4mm, and CCV_6mm in eyes with bullous keratopathy.

RESULTS

The levels of protein, ILs-4, -6, -8, -10, -12p70, and -17A, MCP-1, IFN-γ, E-selectin, P-selectin, and sICAM-1 were significantly higher in eyes with bullous keratopathy compared with those of the normal control subjects (all P < .0025). CCT was significantly correlated with the levels of IL-13 (r = 0.551, P = .0009) and sICAM-1 (r = 0.448, P = .0005). CCV_4mm was significantly correlated with the levels of IL-13 (r = 0.514, P = .0022) and sICAM-1 (r = 0.404, P = .0019). CCV_6mm was significantly correlated with the level of sICAM-1 (r = 0.459, P = .0003).

CONCLUSION

The severity of corneal edema in eyes with bullous keratopathy was associated with the levels of specific cytokines in the AqH.

Monitoring Neurodegeneration in Glaucoma: Therapeutic Implications

Glaucoma is one of the leading causes of blindness globally, and is characterized by loss of retinal ganglion cells (RGCs). Because vision loss in glaucoma is not reversible, therapeutic interventions early in disease are highly desirable. However, owing to the current limitations in evaluating glaucomatous neurodegeneration, it is challenging to monitor the disease severity and progression objectively, and to design rational therapeutic strategies accordingly. Therefore, there is a clear need to identify quantifiable molecular biomarkers of glaucomatous neurodegeneration. As such, in our opinion, molecular biomarker(s) that specifically reflect stress or death of RGCs, and which correlate with disease severity, progression, and response to therapy, are highly desirable.