The risk of uveitis due to prostaglandin analogs in pediatric glaucoma

PURPOSE

To examine the incidence of uveitis in children prescribed prostaglandin analogs (PGAs) for glaucoma.

METHODS

In this dual-center cohort study, the medical records of consecutive patients <18 years old treated with a PGA between January 1, 2012, and December 31, 2018, were reviewed retrospectively. Patients with all forms of glaucoma, including those with a prior history of uveitis, were included. Patients who had been on a PGA prior to their first recorded visit were excluded. Patient charts were reviewed for new or recurrent uveitis during the first year of PGA therapy.

RESULTS

A total of 103 children (147 eyes) were included, with a total PGA exposure of 1,352 child-months. Ninety-eight children (142 eyes) tolerated the PGA without an episode of uveitis. Five patients with a documented prior history of uveitis experienced a unilateral episode of uveitis. A review of their medical records identified prescribed or unscheduled decrease in topical steroids or immunosuppressive medication as the most likely cause of uveitis recurrence.

CONCLUSIONS

This study provides further evidence that PGAs are unlikely to induce uveitis in children being treated for glaucoma and suggests that this may also be true in those with a history of uveitis. We are unable to evaluate whether PGAs make recurrence more likely or the tapering of steroids more difficult.

Lower Relapses Rate With Infliximab Versus Adalimumab in Sight-Threatening Uveitis: A Multicenter Study of 330 Patients

PURPOSE

To compare the relapse rate of sight-threatening noninfectious uveitis (NIU) in patients treated with infliximab (IFX) or adalimumab (ADA).

DESIGN

Observational retrospective multicenter study.

METHODS

A total of 330 patients (median age, 36 years; interquartile range, 27-54), 45.2% men) with sight-threatening NIU (ie, retinal vasculitis and/or macular edema) treated with anti-tumor necrosis factor [TNF]-α agents (IFX intravenously at 5 mg/kg at weeks 0, 2, 6, and every 4 to 6 weeks or ADA subcutaneously at 80 mg, then 40 mg every 2 weeks). Data were obtained retrospectively from patients' medical records. Main outcome measures were relapse rate, complete response of NIU, corticosteroid sparing effect, and safety.

RESULTS

Main etiologies of uveitis included Behçet disease (27%), idiopathic juvenile arthritis (5.8%), and sarcoidosis (5.5%). The estimated relapse rate at 6 months after introduction of biological agents was 13% (95% CI = 0.009-0.16). IFX was associated with less relapse risk than ADA (hazard ratio [HR] = 0.52, 95% CI = 0.36- 0.77, P = .001). ADA and IFX were comparable in terms of complete response rate of NIU as well as corticosteroid-sparing effect. Behçet disease was associated with higher odds of complete response (HR = 2.04, 95% CI = 1.16 -3.60, P = .01] and lower relapse rate (HR = 0.53, 95% CI = 0.33-0.85, P = .009) than other causes of NIU with anti-TNF-α agents.

CONCLUSIONS

In sight-threatening NIU, IFX seems to be associated with a lower relapse rate than ADA.

Anti-Inflammatory Effects of GM1 Ganglioside on Endotoxin-Induced Uveitis in Rats

Exogenous ganglioside GM1 has been reported to exert an immunomodulatory effect. We investigated the anti-inflammatory effect of GM1 ganglioside on endotoxin-induced uveitis (EIU) in rats and RAW 264.7 macrophages. Methods: EIU was induced in Lewis rats by administering a subcutaneous injection of lipopolysaccharide (LPS). GM1 was injected intraperitoneally for three consecutive days prior to the LPS injection. Twenty-four hours after the LPS injection, the integrity of the blood-aqueous barrier was evaluated by determining the protein concentration and number of infiltrating cells in the aqueous humor (AqH). Immunohistochemical and Western blot analyses of the iris-ciliary body (ICB) were performed to evaluate the effect of GM1 on the LPS-induced expression of cyclooxygenase-2 (COX-2) and intercellular adhesion molecule-1 (ICAM-1). The effect of GM1 on proinflammatory mediators and signaling cascades was examined in LPS-stimulated RAW 264.7 cells using Western blotting and immunofluorescence staining to further clarify the underlying anti-inflammatory mechanism. Results: GM1 significantly reduced the protein concentration and number of infiltrating cells in the AqH of rats with EIU. GM1 also decreased the LPS-induced expression of the ICAM-1 and COX-2 proteins in the ICB. In RAW 264.7 cells, GM1 inhibited the proinflammatory mediators induced by LPS, including inducible nitric oxide synthase (iNOS), COX-2, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6), and this inhibitory effect was potentially mediated by suppressing transforming growth factor-β-activated kinase 1 (TAK1) and reactive oxygen species (ROS)-mediated activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs). Conclusions: Based on this study, GM1 may be a potential anti-inflammatory agent for ocular inflammatory diseases.

Risk of Elevated Intraocular Pressure With Difluprednate in Patients With Non-Infectious Uveitis

PURPOSE

To evaluate the risk factors associated with clinically important intraocular pressure (IOP) elevation with topical difluprednate treatment in patients with non-infectious uveitis.

DESIGN

Retrospective cohort study.

METHODS

Fifty-four eyes of 54 patients with non-infectious uveitis treated with topical difluprednate at the current institution were included. Demographics and clinical characteristics of uveitis patients were collected. The main outcome measure was development of clinically important IOP elevation defined as IOP ≥21 mmHg and an increase of ≥10 mmHg from baseline.

RESULTS

A clinically important IOP elevation was observed in 17 patients (31.5%). The mean time to clinically important IOP elevation was 7.4±4.8 weeks (range 3-19). Statistically significant risk factors for incident clinically important IOP elevation were being a child (adjusted hazard ratio [aHR] 7.85 [95% CI 1.48-41.56], P = .02) and concurrent use of systemic steroids (aHR 5.31 [95% CI 1.18-24.00], P = .03). Patients with concurrent systemic corticosteroids developed clinically important IOP elevation earlier than those without systemic corticosteroid (mean 5.7±3.4 [range 3-14] vs 10.4±5.7 [range 4-19] weeks, P = .05). Incident IOP ≥30 mmHg occurred in 7 patients (13.0%). All patients responded well to the cessation of difluprednate and/or use of topical antiglaucomatous agents and no eyes required glaucoma surgery.

CONCLUSIONS

This study demonstrated that clinically important IOP elevation is common in uveitis patients with topical difluprednate treatment. Children and patients with concurrent systemic corticosteroids are at substantial risk of developing clinically important IOP elevation.

Therapeutic Effect of IL-38 on Experimental Autoimmune Uveitis: Reprogrammed Immune Cell Landscape and Reduced Th17 Cell Pathogenicity

Purpose

The purpose of this study was to elucidate the effects of interleukin (IL)-38 on experimental autoimmune uveitis (EAU) and its underlying mechanisms.

Methods

Mice with EAU were treated with IL-38, and the retinas and cervical draining lymph nodes (CDLNs) were analyzed by flow cytometry. Single-cell RNA sequencing (scRNA-seq) was conducted to analyze the immune cell profiles of CDLNs from normal, EAU, and IL-38-treated mice.

Results

Administration of IL-38 attenuated EAU symptoms and reduced the proportion of T helper 17 (Th17) and T helper 1 (Th1) cells in the retinas and CDLNs. In scRNA-seq analysis, IL-38 downregulated the IL-17 signaling pathway and reduced the expression of Th17 cell pathogenicity-related genes (Csf2 and Il23r), findings which were also confirmed by flow cytometry. In vitro, IL-38 reduced the granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation function of IL-23 and inhibited IL-23R expression in Th17 cells. Moreover, when co-cultured with Th17 cells, IL-38 prevented IL-23 production in antigen-presenting cells (APCs).

Conclusions

Our data demonstrate the therapeutic effect of IL-38 on EAU, and suggest that the effect of IL-38 may be caused by dampening of the GM-CSF/IL-23R/IL-23 feedback loop between Th17 cells and APCs.

Annexin A1 Mimetic Peptide and Piperlongumine: Anti-Inflammatory Profiles in Endotoxin-Induced Uveitis

Uveitis is one of the main causes of blindness worldwide, and therapeutic alternatives are worthy of study. We investigated the effects of piperlongumine (PL) and/or annexin A1 (AnxA1) mimetic peptide Ac2-26 on endotoxin-induced uveitis (EIU). Rats were inoculated with lipopolysaccharide (LPS) and intraperitoneally treated with Ac2-26 (200 µg), PL (200 and 400 µg), or Ac2-26 + PL after 15 min. Then, 24 h after LPS inoculation, leukocytes in aqueous humor, mononuclear cells, AnxA1, formyl peptide receptor (fpr)1, fpr2, and cyclooxygenase (COX)-2 were evaluated in the ocular tissues, along with inflammatory mediators in the blood and macerated supernatant. Decreased leukocyte influx, levels of inflammatory mediators, and COX-2 expression confirmed the anti-inflammatory actions of the peptide and pointed to the protective effects of PL at higher dosage. However, when PL and Ac2-26 were administered in combination, the inflammatory potential was lost. AnxA1 expression was elevated among groups treated with PL or Ac2-26 + PL but reduced after treatment with Ac2-26. Fpr2 expression was increased only in untreated EIU and Ac2-26 groups. The interaction between Ac2-26 and PL negatively affected the anti-inflammatory action of Ac2-26 or PL. We emphasize that the anti-inflammatory effects of PL can be used as a therapeutic strategy to protect against uveitis.

Intravitreal lupeol: A new potential therapeutic strategy for noninfectious uveitis

Lupeol is a pentacyclic triterpene with known anti-inflammatory effects. However, its role in the treatment of noninfectious uveitis has not been explored. This work investigated anti-inflammatory activity of lupeol in ocular tissues with in vitro and in vivo models. First, we evaluated the effect of lupeol (100 µM) on inflammatory response induced by lipopolysaccharide (LPS) in retinal pigment epithelium cells (ARPE-19) by measuring levels of released interleukins (IL-6 and IL-8). Then, we investigated the anti-inflammatory action of intravitreal lupeol in a rodent model of panuveitis induced by Mycobacterium bovis Calmette-Guérin Bacillus (BCG). Rats were submitted to electroretinography and clinical analyses on days 3, 7, and 15 after uveitis induction. In addition, histopathological analysis, and indirect quantification of myeloperoxidase (MPO) and N-acetylglucosaminidase (NAG) in the posterior segment were performed. Treatment with lupeol (100 µM) significantly decreased IL-6 and IL-8 levels in comparison to untreated LPS-activated ARPE-19 cells. This reduction was similar to that detected in ARPE-19 cells treated with dexamethasone. The results of the in vivo assay demonstrated that intravitreal lupeol is able to modulate inflammation in the anterior and posterior segment of the rat eyes, indicating that it should be further investigated as a novel potential candidate for management of uveitis.

Intravitreal Steroid Treatment for Uveitis Associated with Dabrafenib and Trametinib for Metastatic Cutaneous Melanoma

Purpose: To report a case of bilateral retinal inflammation under long-term therapy with dabrafenib/trametinib for metastatic cutaneous melanoma.Methods: Retrospective chart review.Results: A 59-year-old patient with metastatic cutaneous melanoma diagnosed in 2004 under treatment with dabrafenib/trametinib since 2014 presented to our department with intraretinal hemorrhage and extrafoveal macula edema on the right eye and optic disc swelling on the left eye. The patient did not report visual complaints. After cessation of dabrafenib/trametinib and subconjunctival and intravitreal corticosteroid injections, optic disc swelling on the left eye recovered after 6 months. The macula edema on the right eye was treated with one intravitreal anti-VEGF (vascular endothelial growth factor) injection after encroaching upon the fovea 10 months after initial presentation. The final visual acuity was 20/20 on both eyes.Conclusion: Even after years of treatment with low dose dabrafenib/trametinib, ocular toxicity can develop. Such cases can respond well to intravitreal corticosteroids.

The association between immune checkpoint or BRAF/MEK inhibitor therapy and uveitis in patients with advanced cutaneous melanoma

BACKGROUND

Treatment with immune checkpoint and BRAF/MEK inhibitors has significantly improved the survival of patients with advanced cutaneous melanoma and other metastatic malignancies. Therapy-related uveitis is a rare ocular adverse event, which may potentially lead to legal blindness. The epidemiology of treatment-related uveitis is currently insufficiently known.

PATIENTS AND METHODS

In this cohort study, we asked whether exposure to either immune checkpoint or BRAF/MEK inhibitors was associated with a higher risk of developing uveitis compared with the general population. Based on a Bayesian framework, we estimated the probability of developing uveitis with a right-censored, exponential survival model using data from the Zurich Melanoma Registry. The registry included all adult patients treated for advanced cutaneous melanoma between January 2008 and December 2018 at the University Hospital of Zurich, Switzerland.

RESULTS

In total, 304 patients (64%) were treated with immune checkpoint and 186 patients (38%) with BRAF/MEK inhibitors. Median follow-up time was 74 days (interquartile range: 57-233 days). Eleven patients developed uveitis and 30 patients died. We estimated the probability of developing uveitis per year in the general population as 0.05% (95% credibility interval [CrI]: 0.02%-0.1%). Corresponding posterior probabilities of treatment-related uveitis were 3.48% (95% CrI: 0.93%-7.49%) and 5.04% (95% CrI: 2.07%-9.19%) for immune checkpoint or BRAF/MEK inhibitors (posterior probability for difference: 76%).

CONCLUSIONS

Immune checkpoint and particularly BRAF/MEK inhibitor therapies are associated with an increase in the risk of developing uveitis. Treatment-related uveitis is not associated with systemic adverse events of immune checkpoint or BRAF/MEK inhibitors.

SHP-1 suppresses endotoxin-induced uveitis by inhibiting the TAK1/JNK pathway

We investigated how Src-homology 2-domain phosphatase-1 (SHP-1) regulates the inflammatory response in endotoxin-induced uveitis (EIU), and the signalling pathways involved. One week after intravitreal injection of short hairpin RNA targeting SHP-1 or SHP-1 overexpression lentivirus in rats, we induced ocular inflammation with an intravitreal injection of lipopolysaccharide (LPS). We then assessed the extent of inflammation and performed full-field electroretinography. The concentrations and retinal expression of various inflammatory mediators were examined with enzyme-linked immunosorbent assays and Western blotting, respectively. SHP-1 overexpression and knockdown were induced in Müller cells to study the role of SHP-1 in the LPS-induced inflammatory response in vitro. Retinal SHP-1 expression was up-regulated by LPS. SHP-1 knockdown exacerbated LPS-induced retinal dysfunction and increased the levels of proinflammatory mediators in the retina, which was abrogated by a c-Jun N-terminal kinase (JNK) inhibitor (SP600125). SHP-1 overexpression had the opposite effects. In Müller cells, the LPS-induced inflammatory response was enhanced by SHP-1 knockdown and suppressed by SHP-1 overexpression. SHP-1 negatively regulated the activation of the transforming growth factor-β-activated kinase-1 (TAK1)/JNK pathway, but not the nuclear factor-κB pathway. These results indicate that SHP-1 represses EIU, at least in part, by inhibiting the TAK1/JNK pathway and suggest that SHP-1 is a potential therapeutic target for uveitis.

Uveitis occurrence in patients with ankylosing spondylitis according to the type of tumour necrosis factor inhibitor: a cohort study of 175 patients

OBJECTIVES

To compare the occurrence of non-infectious uveitis based on the type of tumour necrosis factor (TNF) inhibitor used to manage spondyloarthritis in ankylosing spondylitis (AS) patients.

METHODS

The occurrence (new-onset and recurrence) of uveitis was reviewed retrospectively in AS patients receiving different TNF inhibitor therapies (adalimumab [ADA], infliximab [IFX], etanercept [ETN], and golimumab [GOL]) for the management of spondyloarthritis from 2005 to 2018. Kaplan-Meier analysis was performed to calculate the cumulative occurrence rates of uveitis during TNF inhibitor therapy, and a log-rank test was used to analyse differences between the survival curves. Multivariable Cox proportional-hazards models were used to compute hazard ratios (HRs) of different TNF agents for uveitis occurrence after adjusting for concurrent confounding factors.

RESULTS

The three-year cumulative occurrence rates of uveitis were significantly different according to the type of anti-TNFs used (23.1% in IFX, 18.5% in ETN, and 11.9% in ADA+GOL group) (p=0.020). The risk of new-onset uveitis was similar for different drugs. However, the IFX group showed a 5.4 times higher risk of recurrence than the ADA+GOL group (p=0.022). After adjusting for other confounding factors, IFX use was independently associated with a more frequent occurrence of uveitis in AS patients (HR=2.01; p=0.011).

CONCLUSIONS

A significant number of AS patients who received anti-TNF therapy developed uveitis. Different types of anti-TNF drugs were associated with uveitis recurrence. Particularly, chimeric mouse-human monoclonal antibody (IFX) was found to increase the risk of uveitis occurrence compared to humanised monoclonal antibody (ADA or GOL).

Uveitis and cystoid macular oedema secondary to topical prostaglandin analogue use in ocular hypertension and open angle glaucoma

BACKGROUND

Of the side effects of prostaglandin analogues (PGAs), uveitis and cystoid macular oedema (CME) have significant potential for vision loss based on postmarket reports. Caution has been advised due to concerns of macular oedema and uveitis. In this report, we researched and summarised the original data suggesting these effects and determined their incidence.

METHODS

Preferred Reporting Items for Systematic review and Meta-Analyses guidelines were followed. Studies evaluating topical PGAs in patients with ocular hypertension or open angle glaucoma were included. MEDLINE, PubMed, EMBASE, CINAHL, Web of Science, Cochrane Library, LILACS and ClinicalTrials.gov were searched between 1946 and 2019. Experimental studies, animal studies and randomised studies with other intraocular pressure-lowering eye drops were excluded.

RESULTS

214 studies (28 232 patients) met the inclusion criteria. Using prospective data, the incidence of uveitis and CME among PGA users were 62/28 232 (0.22%) and 25/28 232 (0.09%), respectively. A higher frequency of both uveitis and CME were found among latanoprost users compared with bimatoprost. There were 21 case studies reporting CME including 48 eyes in 43 patients. 47 of 48 eyes (97.9%) had previous incisional ocular surgery. 8 eyes were re-challenged, of which 7 (87.5%) recurred. 7 case studies reported uveitis in 15 eyes of 10 patients. 7 of 15 eyes (46.7%) were either pseudophakic or aphakic. 6 eyes were re-challenged, and all 6 (100%) recurred.

CONCLUSIONS

Cases of uveitis or CME revealed a confounding effect of ocular surgery, aphakia or subluxed intraocular lens. PGAs may be used in non-surgical patients without concern of causing CME or uveitis. The incidences of PGA-associated CME and uveitis are rare with limited prospective studies on the cause-effect relationship.

Sarcoid-like Granulomatous Intraocular Inflammation Caused by Vemurafenib Treatment for Metastatic Melanoma

Vemurafenib is a potent inhibitor of genetically activated BRAF, which is responsible for tumoral proliferation in cutaneous melanoma. A 56-year-old man receiving vemurafenib therapy presented with uveitis. Over the course of the disease, he developed bilateral, granulomatous uveitis with multiple peripheral chorioretinal lesions. Serum angiotensin-converting enzyme levels increased. The patient was diagnosed with probable ocular sarcoidosis related to vemurafenib and was treated with an intravitreal dexamethasone implant. This case is the first report that shows the clinical and angiographic features of a patient with vemurafenib-related sarcoid-like granulomatous uveitis.

Selective Cannabinoid 2 Receptor Agonists as Potential Therapeutic Drugs for the Treatment of Endotoxin-Induced Uveitis

(1) Background: The cannabinoid 2 receptor (CB₂R) is a promising anti-inflammatory drug target and development of selective CB₂R ligands may be useful for treating sight-threatening ocular inflammation. (2) Methods: This study examined the pharmacology of three novel chemically-diverse selective CB₂R ligands: CB₂R agonists, RO6871304, and RO6871085, as well as a CB₂R inverse agonist, RO6851228. In silico molecular modelling and in vitro cell-based receptor assays were used to verify CB₂R interactions, binding, cell signaling (ß-arrestin and cAMP) and early absorption, distribution, metabolism, excretion, and toxicology (ADMET) profiling of these receptor ligands. All ligands were evaluated for their efficacy to modulate leukocyte-neutrophil activity, in comparison to the reported CB₂R ligand, HU910, using an in vivo mouse model of endotoxin-induced uveitis (EIU) in wild-type (WT) and CB₂R^-/- mice. The actions of RO6871304 on neutrophil migration and adhesion were examined in vitro using isolated neutrophils from WT and CB₂R^-/- mice, and in vivo in WT mice with EIU using adoptive transfer of WT and CB₂R^-/- neutrophils, respectively. (3) Results: Molecular docking studies indicated that RO6871304 and RO6871085 bind to the orthosteric site of CB₂R. Binding studies and cell signaling assays for RO6871304 and RO6871085 confirmed high-affinity binding to CB₂R and selectivity for CB₂R > CB₁R, with both ligands acting as full agonists in cAMP and ß-arrestin assays (EC₅₀s in low nM range). When tested in EIU, topical application of RO6871304 and RO6871085 decreased leukocyte-endothelial adhesion and this effect was antagonized by the inverse agonist, RO6851228. The CB₂R agonist, RO6871304, decreased in vitro neutrophil migration of WT neutrophils but not neutrophils from CB₂R^-/-, and attenuated adhesion of adoptively-transferred leukocytes in EIU. (4) Conclusions: These unique ligands are potent and selective for CB₂R and have good immunomodulating actions in the eye. RO6871304 and RO6871085, as well as HU910, decreased leukocyte adhesion in EIU through inhibition of resident ocular immune cells. The data generated with these three structurally-diverse and highly-selective CB₂R agonists support selective targeting of CB₂R for treating ocular inflammatory diseases.

Endotoxin-Induced Uveitis in Rodents

Uveitis can affect individuals of all ages, genders, and races and accounts for 10-15% of all cases of blindness. Uveitis represents a diverse array of intraocular inflammatory conditions that can be associated with complications from autoimmune diseases, bacterial infections, viral infections, chemical injuries, and metabolic issues. In rodents, endotoxin-induced uveitis (EIU) is an efficient experimental model to study pathological mechanisms associated with the disease and evaluate the pharmacological efficacy of potential new drug agents. In the EIU model, uveitis is characterized by clinically relevant inflammation, including inflammatory exudates and cells infiltrated into the anterior and vitreous eye chambers. EIU in small animal models, including rats, mice, and rabbits, is characterized by a short-lived uveal inflammation. This inflammation can be facilitated using bacterial endotoxins, such as lipopolysaccharide (LPS). In this chapter, we present a reliable, reproducible, and simplified protocol to induce EIU in mice. This method is flexible and can be applied for EIU induction in other small animals and rodents.

TUBULOINTERSTITIAL NEPHRITIS AND UVEITIS SYNDROME WITH A PRIMARY PRESENTATION OF ACUTE POSTERIOR MULTIFOCAL PLACOID PIGMENT EPITHELIOPATHY

PURPOSE

To report a case of tubulointerstitial nephritis and uveitis syndrome with a primary presentation of acute posterior multifocal placoid pigment epitheliopathy after use of lamotrigine.

METHODS

Retrospective case report with ultra-widefield fundus imaging, optical coherence tomography, and fluorescein angiography.

RESULTS

A 19-year-old woman presented with decreased visual acuity and acute renal failure after starting lamotrigine. Her examination demonstrated 1+ anterior chamber cell and numerous white deep retinal plaque-like lesions predominantly in the macula in both eyes. After extensive ophthalmic and systemic evaluation, the patient was diagnosed with tubulointerstitial nephritis and uveitis syndrome with a primary presentation of acute posterior multifocal placoid pigment epitheliopathy. She had excellent visual recovery with topical and systemic steroids.

CONCLUSION

Acute posterior multifocal placoid pigment epitheliopathy is a rare but important clinical presentation of tubulointerstitial nephritis and uveitis syndrome. Oral corticosteroid treatment can be considered for tubulointerstitial nephritis but is generally not necessary for acute posterior multifocal placoid pigment epitheliopathy.

Uveitis Following Treatment of Verruca Vulgaris with Intralesional Candida Antigen

This is a first literature report of a case of uveitis along with severe systemic symptoms following verruca vulgaris treatment with intralesional Candida antigen. We believe the Candida injection was causative.

Silibinin treatment prevents endotoxin-induced uveitis in rats in vivo and in vitro

Uveitis, an intraocular inflammatory disease, occurs mostly in young people and can result in the loss of socioeconomic capabilities. Silibinin has been shown to exert anti-inflammatory effects in human retinal pigment epithelial (RPE) cells. The present study investigated the anti-inflammatory effect of silibinin pretreatment on endotoxin-induced uveitis (EIU) in rats and the mechanisms by which it exerts these effects. Uveitis was induced via injection of lipopolysaccharides (LPS) into Lewis rats. Twenty-four hours after the LPS injection, histological examination showed that silibinin decreased inflammatory cell infiltration in the anterior segment of the eyes of LPS-treated rats. Analyses of the aqueous humor showed that silibinin decreased cell infiltration, protein concentration, nitric oxide (NO), and prostaglandin (PG)-E2 production. Western blot analysis indicated that silibinin decreased the expression of inducible NO synthase (iNOS), cyclooxygenase (COX-2), and phosphorylated IkB in the iris-ciliary body (ICB). Immunohistochemistry showed that silibinin decreased intercellular adhesion molecule (ICAM-1) expression in the ICB. In addition, western blot analysis showed that silibinin attenuated the expression of iNOS, COX-2, ICAM-1, and nuclear p65 in LPS-treated RAW cells. In conclusion, silibinin pretreatment prevents EIU and the subsequent production of proinflammatory mediators and ICAM-1, at least in part, by blocking the NF-κB–dependent signaling pathway both in vivo and in vitro. These effects may contribute to the silibinin-mediated preventive effects on intraocular inflammatory diseases such as acute uveitis.

[BISPHOSPHONATES AND OCULAR INFLAMMATION]

Bisphosphonates are a group of drugs used for treatment in several bone diseases such as osteoporosis in women, Paget's disease, hypercalcemia of malignancy, primary malignancies of the bone and metastatic bone disease (breast and prostate carcinoma). Numerous reports in the medical literature described ocular side effects in patients treated with these drugs. We report on two patients, treated with bisphosphonates due to malignancy, who presented with unilateral and bilateral uveitis. Treatment of the ocular inflammation should include local and systemic treatment and stopping the systemic use of bisphosphonates. Another alternative is switching to another bisphosphonate with less ocular side effects.

MMP-3 Deficiency Alleviates Endotoxin-Induced Acute Inflammation in the Posterior Eye Segment

Matrix metalloproteinase-3 (MMP-3) is known to mediate neuroinflammatory processes by activating microglia, disrupting blood-central nervous system barriers and supporting neutrophil influx into the brain. In addition, the posterior part of the eye, more specifically the retina, the retinal pigment epithelium (RPE) and the blood-retinal barrier, is affected upon neuroinflammation, but a role for MMP-3 during ocular inflammation remains elusive. We investigated whether MMP-3 contributes to acute inflammation in the eye using the endotoxin-induced uveitis (EIU) model. Systemic administration of lipopolysaccharide induced an increase in MMP-3 mRNA and protein expression level in the posterior part of the eye. MMP-3 deficiency or knockdown suppressed retinal leukocyte adhesion and leukocyte infiltration into the vitreous cavity in mice subjected to EIU. Moreover, retinal and RPE mRNA levels of intercellular adhesion molecule 1 (Icam1), interleukin 6 (Il6), cytokine-inducible nitrogen oxide synthase (Nos2) and tumor necrosis factor α (Tnfα), which are key molecules involved in EIU, were clearly reduced in MMP-3 deficient mice. In addition, loss of MMP-3 repressed the upregulation of the chemokines monocyte chemoattractant protein (MCP)-1 and (C-X-C motif) ligand 1 (CXCL1). These findings suggest a contribution of MMP-3 during EIU, and its potential use as a therapeutic drug target in reducing ocular inflammation.

The efficacy of intravitreal interferon alpha-2b for the treatment of experimental endotoxin-induced uveitis

PURPOSE

To study the efficacy of intravitreal interferon alpha-2b for endotoxin-induced uveitis.

MATERIALS AND METHODS

A total of 36 rabbits were randomly allocated to one of the three groups: (1) received interferon plus balanced-salt solution; (2) received lipopolysaccharide (LPS) plus interferon; and (3) received LPS plus balanced-salt solution. Intraocular inflammation was evaluated by slit-lamp biomicroscopy (standardization of uveitis nomenclature grading), binocular indirect ophthalmoscopy (BIO) score, and histopathology.

RESULTS

Group 2 showed significantly lower mean (±standard deviation) anterior chamber reaction than Group 3 (3.1 ± 0.9 vs. 3.8 ± 0.4) on day 1 postinjection, lower vitreous cells on days 1 through 7 (day 1: 3.1 ± 0.9 vs. 3.8 ± 0.4; day 3: 2.1 ± 1.6 vs. 3.8 ± 0.4; day 7: 1.9 ± 1.3 vs. 3.6 ± 0.7), and lower BIO score on days 1-7 (day 1: 3.3 ± 1.2 vs. 4.4 ± 0.7; day 3: 3.0 ± 1.4 vs. 4.3 ± 0.9; day 7: 2.4 ± 1.4 vs. 3.7 ± 1.2). The protein content of anterior and vitreous aspirates was lower in Group 2 than 3 (1618.5 ± 411.4 vs. 2567.3 ± 330.8 and 2157.0 ± 283.3 vs. 3204.6 ± 259.5, respectively).

CONCLUSION

Intravitreal interferon alpha-2b was effective in controlling endotoxin-induced uveitis.

[The Clinical Signs of Experimental Autoimmune Uveitis]

INTRODUCTION

Autoimmune uveitis is a sight threatening disease which in many cases fails to respond to conventional immunosuppressive or biological therapy. The research in experimental models of autoimmune uveitis helps to find new therapeutical strategies. The aim of this study is to present the clinical and histological signs of experimental autoimmune uveitis (EAU) in mice.

METHODS

EAU was induced in C57BL/6 mice by subcutaneous application of IRBP (interphotoreceptor retinoid binding protein) in complete Freunds adjuvant and intraperitoneal application of pertussis toxin. Clinical evaluation of uveitis was performed in vivo using special imaging system with otoscope. Histological evaluation of uveitis was performed at day 35 post induction of EAU on hematoxylin and eosin stained frozen sections. Clinical and histological grading was used to assess the inflammation intensity of EAU.

RESULTS

The intensity of inflammation is depicted on representative fundus images and histological images of retina at day 35 post induction.

CONCLUSION

The model of EAU is robust and reproducible and allows us to study the immunopathological mechanisms of inflammation and its regulation. The inflammatory signs in our model are similar to findings of posterior uveitis of autoimmune etiology in humans, thus we may apply our experimental results in human medicine.

[Effects of leflunomide on experimental autoimmune uveitis in Lewis rats]

OBJECTIVES

To investigate the protective efficacy of leflunomide on the Lewis rats with experimental autoimmune uveitis (EAU).

METHODS

Complete randomized controlled trials research. Lewis rats were immunized with interphotoreceptor retinoid-binding peptide (IRBP) in order to build the model of EAU. Rats were randomized assigned into four groups, that is control group as A, model group without leflunomide as B, model group with leflunomide administrations as C, and model group with cyclosporine A as D. Rats in group C received intragastric administration of three doses of leflunomide at 3mg/kg/d; 6mg/kg/d; 12mg/kg/d. Rats in group D received 10 mg/kg cyclosporin A were considered as a positive control. Each group has 6 to 8 rats. At the second day of immunization with IRBP, rats were intragastric administrated one time every day till day 13. Rats were investigated for EAU symptoms under slit lamp. Enucleated eyes were collected for sections with HE staining as histopathological evidences at the peak point of disease activity day 14. Treatment effectiveness was evaluated referred by Agarwal standard for clinical EAU and histopathological scoring. The expression of IL-17 in ocular sections was detected by immunohistochemistry (SP method). The expression levels of IL-17 and IFN-γ in the serum were quantified by ELISA. Intracellular expression of IL-17 in the activated CD4+T cells was assessed by flow cytometry. Ocular of rats were harvested and mRNA expression of IL-17 and IFN-γ were quantified through RT-PCR. Continuous variables were reported as mean ± SD. The comparison among groups was done by using analysis of students't test. Nonparametric test was used in Hierarchical data comparison and multiple comparison method was Bonferroni.

RESULTS

The model of EAU disease was built successfully in Lewis rats. With giving IRBP for 14 days, the clinic EAU scores were lower in model rats than those without leflunomide. Moreover, the effects of leflunomide on the clinic EAU scores was dose-dependent. Comparing to vehicle-treated eyes, treatment with leflunomide significantly prevented the onset of EAU-induced ocular inflammation [1.5 (1,2) vs. 3 (3,4), P = 0.0006, P < α', α' = 0.05/15]. The pathological examination showed model rats eye characterized by severe inflammatory cells infiltration and all layers of retina damaged. The pathologic grade was significant higher in model group than in medium dose leflunomide. [3(3, 4) vs. 2(1,3), P = 0.0014, P < α', α' = 0.05/15]. IL-17 was positively expressed in iris, ciliary and retina in model group. While, it was markedly reduced in leflunomide-treated eyes. Flow cytometry detection found that compared with normal group, Th17 cells rates in rats' spleen of model group also increased significantly (8.5% ± 1.3% vs. 0.5% ± 0.2%; t = 8.057, P = 0.000, P < α', α' = 0.05/15). Compared with model group, Th17 cells in spleen of rats in leflunomide groups showed a decreased number by flow cytometry. And it showed dosage dependent. It was significant different between different doses leflunomide treated group compared with control group. The results showed as below, in low dose group (4.1% ± 0.6% vs. 8.5% ± 1.3%; t = 6.372, P = 0.01, P < α', α' = 0.05/15), in medium dose group (2.8% ± 0.2% vs. 8.5% ± 1.3%; t = 4.49, P = 0.002, P < α', α' = 0.05/15) and in high dose group (1.8% ± 0.2% vs. 8.5% ± 1.3%; t = 5.743, P = 0.000, P < α', α' = 0.05/15). Gene expression of IL-17 and IFN-γ were markedly reduced in leflunomide-treated eyes. Leflunomide significantly decreased the serum levels of IL-17 and IFN-γ. Compared with model group, in leflunomide-treated low dosage group (0.603 ± 0.03 vs. 0.787 ± 0.104; t = 0.183, P = 0.002, P < α', α' = 0.05/15), medium dosage group (0.535 ± 0.048 vs. 0.787 ± 0.104; t = 0.252, P = 0.000, P < α', α' = 0.05/15) and high dosage group (0.374 ± 0.051 vs. 0.787 ± 0.104; t = 0.412, P = 0.000, P < α', α' = 0.05/15), IL-17 mRNA showed lower expression. Moreover, IFN-γ mRNA in the tissue of EAU eyes were suppressed by medium dosage leflunomide group (0.375 ± 0.018 vs. 0.427 ± 0.056; t = 0.69, P = 0.001, P < α', α' = 0.05/15) and high leflunomide dosage group respectively (0.367 ± 0.018 vs. 0.427 ± 0.056; t = 0.077, P = 0.000, P < α', α' = 0.05/15). The difference was statistically significant. All the results suggested that IL-17, which was secreted by Th17 cell, a subtype of T lymphocytes, might play an important role in the pathogenesis of uveitis.

CONCLUSIONS

Oral administration of leflunomide effectively suppressed IRBP-induced uveitis in rats, not only reduced exudation in iris but also alleviated the infiltration damage of inflammation cells in fundus. It might be ascribed to the effect that leflunomide could treat inflammation by down-regulating the expressions of IL-17 and IFN-γ. Therefore, it suggested that leflunomide had protective effects against EAU in Lewis rats.