Intraocular Inflammatory Disease Research Articles

SIRT1 activation protects against autoimmune T cell-driven retinal disease in mice via inhibition of IL-2/Stat5 signaling

Sirtuins are a mammalian family of NAD+-dependent histone deacetylases that regulate cell function and survival as well as regulating cell responses under inflammatory conditions. SIRT1 activator treatment in vitro using mouse pLN cells, normal human and ocular Behçet's disease donor PBMC resulted in suppressed T cell proliferation and pro-inflammatory cytokine production. Our data suggest a novel mechanism by which SIRT1 activators contribute to suppression of T cell proliferation by both down regulating STAT5A/B expression and suppression of pSTAT5A/B signaling in response to IL-2. Experimental autoimmune uveoretinitis (EAU) in B10.RIII mice is an antigen-specific cell-mediated model of human intra-ocular inflammatory disease. Infiltrating CD4+ T cells in the retina secrete both IFN-γ and IL-17 and are accompanied by inflammatory granulocytes and macrophages which together result in retinal destruction. Oral SIRT1 activator treatment administered to EAU mice suppressed disease with an accompanying reduction in retinal leukocytic infiltrate, suppressed antigen-specific T cell responses and marked suppression of innate and adaptive pro-inflammatory cytokine production in the eye including IL-6, IL-17A and IFN-γ. In vivo SIRT1 activator treatment also suppressed production of IL-17A, IL-17F, IL-6, TGFβ and IL-22 by pLN cells. Oral SIRT1 activator treatment administered to mice during the efferent phase (days7–14) of EAU was effective at suppressing disease. These observations demonstrate that SIRT1 activation is anti-inflammatory in nature and future targeted activation of SIRT1 shows promise as a potential treatment for non-infectious intra-ocular disorders such as uveitis associated with Behçets disease.

Investigation of the peptidoglycan sensing molecule, PGLYRP-2, in murine inflammatory uveitis

Background/aimPeptidoglycan (PGN) recognition proteins (PGLYRPs) are innate immune molecules that recognise bacterial cell wall PGN, and participate in several inflammatory diseases such as arthritis. We sought to elucidate the contribution...

Interview With Chi-Chao Chan

Chi-Chao Chan, an American board certified ophthalmologist, is the Chief of Immunopathology Section, Laboratory of Immunology and the Head of Histology Core at the National Eye Institute at National Institutes of Health (USA). In 1967, Dr Chan graduated from Chungzhan Medical College in Guangzhou, China and then earned her AB (1972), as well as MD (1975) at Johns Hopkins University (USA). Currently, her research is focusing on primary intraocular (vitreoretinal) lymphoma; uveitis (intraocular inflammatory diseases); and the molecular pathology, animal models, and genetic epidemiology of age-related macular degeneration. Dr Chan spoke to Future Medicinal Chemistry, about the challenges ophthalmic research faces and how the aging population could lead to better drugs.

The 2009 prospective multi-center epidemiologic survey of uveitis in Japan

To investigate etiologic data on intraocular inflammation in Japan collected in the 2009 epidemiologic survey of uveitis in Japan and assess the current state of etiology compared with that reported in a previous survey. Thirty-six university hospitals participated in this prospective etiologic study. Patients who visited the outpatient uveitis clinic of each hospital for the first time between 1 June 2009 and 31 May 2010 were enrolled in the study. Uveitic diseases were diagnosed according to the guidelines when available or following commonly accepted diagnostic criteria. A total of 3,830 patients were enrolled in the survey and 2,556 cases of uveitis were identified, of which 1,274 cases were described as unclassified intraocular inflammation. In the identified cases, the most frequent intraocular inflammatory disease was sarcoidosis (10.6 %), followed by Vogt-Koyanagi-Harada disease (7.0 %), acute anterior uveitis (6.5 %), scleritis (6.1 %), herpetic iridocyclitis (4.2 %), Behçet's disease (3.9 %), bacterial endophthalmitis (2.5 %), masquerade syndrome (2.5 %), Posner-Schlossman syndrome (1.8 %), and retinal vasculitis (1.6 %). The current etiology of uveitis in Japan was elucidated by means of a multi-center prospective survey. Conducting such surveys on a periodic basis may help clinicians in their management of uveitis.

Comparison of idiopathic and secondary uveitis patients seen in a dual pediatric rheumatology-ophthalmology clinic

Purpose Uveitis is an intraocular inflammatory disease that accounts for 10-15% of all cases of total blindness in the U.S. Although uveitis is more prevalent in adults, children comprise approximately 5% of the uveitis population. The most common etiologies of childhood uveitis are idiopathic, infectious, and rheumatologic. Idiopathic uveitis is the most common cause of pediatric uveitis, while uveitis associated with Juvenile Idiopathic Arthritis (JIA) is the most common secondary cause. In 2005, the physicians of Children’s Mercy’s Hospital created a dual Pediatric Rheumatology and Ophthalmology uveitis clinic for patients with ocular inflammation requiring systemic immunosuppressant therapy. An ophthalmologist and rheumatologist jointly evaluate each patient, and formulate a comprehensive plan with the patient and family. To our knowledge, this is the only pediatric uveitis clinic in the U.S. staffed by the two subspecialties simultaneously. The aim of this study was to determine if the characteristics of ocular involvement differ between severe Idiopathic uveitis (IU) and Secondary uveitis (SU).

Neutralization of IL-17 ameliorates uveitis but damages photoreceptors in a murine model of spondyloarthritis

IntroductionUveitis, or intraocular inflammatory disease, is a frequent extra-articular manifestation of several forms of arthritis. Despite the frequent co-occurrence of uveitis and arthritis, little is understood of the eye's predisposition to this disease. We recently described a previously unreported uveitis in a murine model of spondyloarthropathy triggered by autoimmunity to aggrecan, a prominent proteoglycan (PG) macromolecule in cartilage. In contrast to the joint and spine, wherein interferon-gamma (IFNγ) deficiency reduced disease, IFNγ deficiency worsened uveitis. Given the regulatory role of IFNγ on the Th17 response and the current focus of anti-interleukin-17 therapeutics in patients with uveitis and spondyloarthritis, we sought to determine the extent to which interleukin (IL)-17 mediates uveitis in the absence of IFNγ.MethodsAntigen specific T cell cytokine production was measured in splenocyte cultures using multiplex-ELISA. Transgenic (Tg) mice expressing the T cell receptor (TCR) recognizing the dominant arthritogenic epitope in the G1 domain of PG (TCR-Tg), also lacking IFNγ, were immunized with PG. Mice were then systemically administered an anti-IL-17 neutralizing antibody. The onset and severity of peripheral arthritis was evaluated by clinical scoring criteria and histology. Uveitis was assessed using intravital videomicroscopy, which visualizes leukocyte trafficking within the vasculature and tissue of the iris, and by histology.ResultsTCR-Tg splenocytes stimulated in vitro with recombinant G1 peptide demonstrated exacerbated production of cytokines, such as macrophage inflammatory protein (MIP)-1α, MIP-1β, IL-1β, and most notably IL-17A as a consequence of IFNγ deficiency. In vivo, IL-17 inhibition prevented the component of PG-induced arthritis that occurs independently of IFNγ. Blockade of IL-17 ameliorated the ongoing leukocyte trafficking responses within the iris vasculature and tissue, which coincided with reduced infiltration of leukocytes within the anterior and posterior eye segments. However, the anti-IL-17 treatment resulted in unanticipated photoreceptor toxicity.ConclusionsThese data support a protective, regulatory role for IFNγ in suppression of IL-17-mediated intraocular disease and to a lesser extent, joint disease. The unanticipated photoreceptor toxicity raises some caution regarding the use of anti-IL-17 therapeutics until the mechanism of this potential effect is determined.

The NLRP3 inflammasome is active but not essential in endotoxin-induced uveitis.

The inflammasome complex involving caspase-1 and nucleotide-binding domain, leucine-rich repeat containing protein (NLRP)3, also known as NALP3 or cryopyrin is important for host responses to microbial pathogens and several autoinflammatory diseases. We investigated the extent to which NLRP3 and caspase-1 control ocular interleukin (IL)-1β production and severity of uveitis (intraocular inflammatory disease) in an established, acute inflammatory uveitis model, endotoxin-induced uveitis (EIU). Expression of NLRP3, its adaptor molecule ASC, also known as PYCARD (PYD and CARD domain containing), and caspase-1 were examined by immunoblotting. IL-1β production was measured by enzyme-linked immunosorbent assay (ELISA). Using knockout mice, roles for caspase-1 and NLRP3 were examined in uveitis induced by intraocular injection of Escherichia coli lipopolysaccharide (LPS). NLRP3, ASC, and caspase-1 proteins are constitutively expressed in eye tissue. During EIU, IL-1β protein production increases; this requires the presence of both caspase-1 and NLRP3. However, severity of EIU is not altered by deficiency in either caspase-1 or NLRP3, as assessed by both intravital microscopy and histology. These data identify the importance of the NLRP3 inflammasome for IL-1β production in the eye, yet indicate that its participation in EIU is nonessential.

Therapeutic Dosing of Fingolimod (FTY720) Prevents Cell Infiltration, Rapidly Suppresses Ocular Inflammation, and Maintains the Blood-Ocular Barrier

Fingolimod (FTY720) is an FDA-approved therapeutic drug with efficacy demonstrated in experimental models of multiple sclerosis and in phase III human multiple sclerosis trials. Fingolimod prevents T-cell migration to inflammatory sites by decreasing expression of the sphingosine-1 phosphate receptor normally required for egress from secondary lymphoid tissue. As a preclinical model of human uveitis, experimental autoimmune uveoretinitis permits assessment of immunotherapeutic efficacy. Murine experimental autoimmune uveoretinitis is induced by activation of retinal antigen-specific CD4(+) T cells that infiltrate the eye. High-dose fingolimod treatment administered before disease onset reduces ocular infiltration within hours of administration and suppresses clinicopathologic expression of experimental autoimmune uveoretinitis. In the present investigation of the efficacy of fingolimod treatment for established disease, single-dose treatment was effective and immunosuppressive ability was maintained through a dose range, demonstrating significant and rapid reduction in CD4(+) cell infiltration at clinically relevant therapeutic doses of fingolimod. A repeated-treatment regimen using a dose similar to that in current multiple sclerosis patient protocols significantly reduced infiltration within 24 hours of administration; importantly, repeated doses did not compromise the vascular integrity of the blood-ocular barrier. On withdrawal of fingolimod, drug-induced remission was lost and recrudescence of clinical disease was observed. These results support a strong therapeutic potential for fingolimod as an acute rescue therapy for the treatment of ocular immune-mediated inflammation.

Intravitreal treatment with antisense oligonucleotides targeting tumor necrosis factor-α in murine herpes simplex virus type 1 retinitis

Tumor necrosis factor alpha (TNF-α) is a proinflammatory cytokine known to participate in intraocular inflammatory disease. This study investigated whether treatment with intravitreal antisense-oligonucleotides (ASON) targeting TNF-α mRNA affects the progression of herpes simplex virus 1 (HSV-1) retinitis in mice. The in vivo uptake of the oligonucleotid after intravitreal injection was determined with FITC-labeled TNF-α ASON. HSV-retinitis was induced on day 0 by the injection of HSV-1 (KOS strain) into the anterior chamber (AC) of the right eyes of BALB/c mice (von Szily model). The left contralateral eyes were injected intravitreally on day 7 with TNF-α ASON, sequence-unspecific control ASON (CON), or buffer. The clinical course of retinitis, ocular inflammatory cell-infiltration, TNF-α expression in the eye by ELISA, delayed-type hypersensitivity (DTH) reaction, virus-neutralizing antibody titers in the serum, uptake of [3H]thymidine from regional lymph node (rln) cells, and viral content in the eyes were determined. In vivo, strong fluorescence of FITC- TNF-α ASON was detected in the choroid and retina up to 3days after intravitreal injection, but none in the rln. After treatment of eyes with ASON, decreased expression of TNF-α in the eye, and reduced incidence and severity of retinitis on day 10 after infection (P < 0.05) could be found. The other parameters were not significantly influenced after TNF-α ASON treatment. TNF-α participates in the pathology of HSV-1 retinitis. Local inhibition of TNF-α mRNA by intraocular TNF-α ASON injection did not influence the systemic HSV-specific immune response or the antiviral response in the eye, but reduced ocular inflammatory bystander damage.

The Influence of Uveitis on Patients with Immune-Mediated Inflammatory Disease

Uveitis, defined as an intraocular inflammatory disease, is one of the main causes of visual impairment in the working-age population. The condition often coexists with other immune-mediated inflammatory diseases (IMID) and greatly contributes to reduced quality of life (QOL) in affected individuals. While visual acuity remains the most commonly used measure of visual function in patients with uveitis, the US National Eye Institute Visual Function Questionnaire is frequently used to assess their health-related QOL. However, despite intuition that coexisting uveitis might exaggerate already impaired QOL in patients with IMID, specific questions related to their visual functioning are rarely included in clinical trials or assessed in daily practice. We provide an overview of the occurrence and significance of uveitis in patients with IMID, its consequences, and the role of tumor necrosis factor-α inhibitors in overall treatment approaches.

Suppressor of Cytokine Signaling-1 (SOCS1) Inhibits Lymphocyte Recruitment into the Retina and Protects SOCS1 Transgenic Rats and Mice from Ocular Inflammation

Suppressors of cytokine signaling (SOCS) proteins regulate the intensity and duration of cytokine signals and defective expression of SOCS1 and SOCS3 has been reported in a number of human diseases. The purpose of this study was to investigate the role of SOCS1 in intraocular inflammatory diseases (uveitis) and whether SOCS1 expression is defective in patients with ocular inflammatory diseases. Blood from patients with scleritis or healthy human volunteers was analyzed for SOCS expression by RNase protection assay and RT-PCR. The authors generated SOCS1 transgenic rats and mice (SOCS1-Tg), induced experimental autoimmune uveoretinitis (EAU) by active immunization with interphotoreceptor retinal binding protein or adoptive transfer of uveitogenic T cells, and investigated effects of SOCS1 overexpression on EAU. SOCS1-mediated protection of retinal cells from apoptosis was assessed by annexin V staining. Induction of cytokine-induced SH2 protein was comparable between patients and volunteers, whereas 80% of lymphocytes from patients with scleritis failed to induce SOCS1 in response to IL-2. Compared with wild-type littermates, SOCS1-Tg rats/mice developed less severe EAU. Constitutive overexpression of SOCS1 in retina inhibited expression of chemokines (CCL17, CCL20, CXCL9, CXCL10), reduced Th17/Th1 expansion, and inhibited recruitment of inflammatory cells into the retina. The authors also show that SOCS1 protected retinal cells from staurosporine as well as H₂O₂-induced apoptosis. Defective expression of SOCS1 in patients with scleritis, taken together with SOCS1-mediated protection of neuroretinal cells from apoptosis, suggest that SOCS1 has neuroprotective function in the retina, implying that administration of SOCS1 mimetic peptides may be useful in treating uveitis or scleritis.

C5a contributes to intraocular inflammation by affecting retinal pigment epithelial cells and immune cells

BackgroundThe complement activation molecule C5a has been found in the eye and is implicated in the pathogenesis of ocular inflammatory diseases. In this study, the authors sought to investigate C5a's...

Oxidative photoreceptor cell damage in autoimmune uveitis

Uveitis comprises an extensive array of intraocular inflammatory diseases and often results in irreversible visual loss. Experimental autoimmune uveitis (EAU) is an animal model used to study human uveitis. Both innate and adaptive immune responses are known to mediate retinal damage in EAU. The innate immune response occurs first with activation of toll-like receptors which upregulate inflammatory cytokines, leading to oxidative stress; subsequently, the adaptive immune response results in inflammatory cytokine upregulation and mitochondrial oxidative stress. In early EAU, mitochondrial DNA is damaged before inflammatory cellular infiltration and alters mitochondrial protein levels and the functions of mitochondria in AU. Our recent study confirms the importance of TLR4 in the generation of inflammatory cytokines, initiation of oxidative DNA damage, and induction of mitochondrial oxidative stress. Like EAU, sympathetic ophthalmia also results in photoreceptor mitochondrial oxidative damage. Agents that prevent mitochondrial oxidative stress and photoreceptor apoptosis may help prevent retinal damage and preserve vision in uveitis.

A look at autoimmunity and inflammation in the eye

Autoimmune and inflammatory uveitis are a group of potentially blinding intraocular inflammatory diseases that arise without a known infectious trigger and are often associated with immunological responses to unique retinal proteins. In the United States, about 10% of the cases of severe visual handicap are attributed to this group of disorders. As I discuss here, experimental models of ocular autoimmunity targeting retinal proteins have brought about a better understanding of the basic immunological mechanisms involved in the pathogenesis of uveitis and are serving as templates for the development of novel therapies.

Human herpesvirus 6‐A, 6‐B, and 7 in vitreous fluid samples

Human herpesvirus 6 and 7 (HHV-6, HHV-7) have been associated with several neurologic syndromes and have been detected in nervous tissue from healthy persons; however, only two cases of HHV-6A have been reported to be associated with intraocular inflammatory disease. Vitreous fluid was tested from 101 patients, including 69 samples from patients with ocular inflammation including CMV retinitis, idiopathic retinitis, iritis, and vitritis, for HHV-6A, HHV-6B, and HHV-7 DNA by PCR. HHV-6A DNA (4,950 copies per ml) was detected in vitreous fluid from one patient with CMV retinitis, HHV-6B DNA (10,140 copies per ml) was detected in vitreous fluid from one patient with idiopathic ocular inflammation in the absence of CMV DNA, and HHV-7 was not detected in any of the vitreous samples. HHV-6A, HHV-6B, and HHV-7 DNA are detectable in less than 2% of vitreous samples in patients with ocular inflammation.

The causes of uveitis in a referral centre of Northern Italy

Uveitis is a complex intraocular inflammatory disease resulting from several aetiological entities that are linked to geographical, genetic and socioeconomic variables. The purpose of this study was to provide an overview of the distribution patterns of uveitis as seen in a nationwide referral centre at a community hospital in Reggio Emilia, northern Italy, and to compare our data with those reported in previously published international series. The records of 1064 patients of Italian origin with uveitis referred to the Immunology Ocular Unit of the Arcispedale S. Maria Nuova Hospital in Reggio Emilia from 2002 to 2008 were classified and analysed. Data regarding sex, race, residence, age at presentation and at onset of uveitis, ocular involvement, clinical characteristics, ocular condition, and systemic disease associations were collected. The mean age at onset of uveitis was 41 years (range: 1-94), and the male-to-female ratio was 1:1.2. Anterior uveitis was the most common location (51.2%), followed by posterior uveitis (23.4%), panuveitis (19.6%), and intermediate uveitis (5.8%). The most frequent entities included Fuchs uveitis (22.7%), herpetic anterior uveitis (9.9%), toxoplasmosis (6.9%), HLA-B27-associated anterior uveitis (5.3%), and Behçet's disease (5.3%). The distribution we observed of the most common disease entities conformed to previous international series. In our series, Fuchs uveitis represented the most common diagnosis (22.7%, 45% of anterior uveitis). The high percentage of specific diagnosis (74%) can be explained by the establishment of new disease categories over time as well as by a systematic multi-disciplinary diagnostic approach.

A New Treatment for Intraocular Inflammatory Diseases

A New Treatment for Intraocular Inflammatory Diseases

Systemic and local anti-C5 therapy reduces the disease severity in experimental autoimmune uveoretinitis.

Activation of complement occurs during autoimmune retinal and intraocular inflammatory disease as well as neuroretinal degenerative disorders. The cleavage of C5 into fragments C5a and C5b is a critical event during the complement cascade. C5a is a potent proinflammatory anaphylatoxin capable of inducing cell migration, adhesion and cytokine release, while membrane attack complex C5b-9 causes cell lysis. Therapeutic approaches to prevent complement-induced inflammation include the use of blocking monoclonal antibodies (mAb) to prevent C5 cleavage. In these current experiments, the rat anti-mouse C5 mAb (BB5.1) was utilized to investigate the effects of inhibition of C5 cleavage on disease progression and severity in experimental autoimmune uveoretinitis (EAU), a model of organ-specific autoimmunity in the eye characterized by structural retinal damage mediated by infiltrating macrophages. Systemic treatment with BB5.1 results in significantly reduced disease scores compared with control groups, while local administration results in an earlier resolution of disease. In vitro, contemporaneous C5a and interferon-gamma signalling enhanced nitric oxide production, accompanied by down-regulation of the inhibitory myeloid CD200 receptor, contributing to cell activation. These experiments demonstrate that C5 cleavage contributes to the full expression of EAU, and that selective C5 blockade via systemic and local routes of administration can suppress disease. This presents great therapeutic potential to protect against tissue damage during autoimmune responses in the retina or inflammation-induced degenerative disease.

Administration of Mycobacterium leprae rHsp65 Aggravates Experimental Autoimmune Uveitis in Mice

The 60kDa heat shock protein family, Hsp60, constitutes an abundant and highly conserved class of molecules that are highly expressed in chronic-inflammatory and autoimmune processes. Experimental autoimmune uveitis [EAU] is a T cell mediated intraocular inflammatory disease that resembles human uveitis. Mycobacterial and homologous Hsp60 peptides induces uveitis in rats, however their participation in aggravating the disease is poorly known. We here evaluate the effects of the Mycobacterium leprae Hsp65 in the development/progression of EAU and the autoimmune response against the eye through the induction of the endogenous disequilibrium by enhancing the entropy of the immunobiological system with the addition of homologous Hsp. B10.RIII mice were immunized subcutaneously with interphotoreceptor retinoid-binding protein [IRBP], followed by intraperitoneally inoculation of M. leprae recombinant Hsp65 [rHsp65]. We evaluated the proliferative response, cytokine production and the percentage of CD4+IL-17+, CD4+IFN-γ+ and CD4+Foxp3+ cells ex vivo, by flow cytometry. Disease severity was determined by eye histological examination and serum levels of anti-IRBP and anti-Hsp60/65 measured by ELISA. EAU scores increased in the Hsp65 group and were associated with an expansion of CD4+IFN-γ+ and CD4+IL-17+ T cells, corroborating with higher levels of IFN-γ. Our data indicate that rHsp65 is one of the managers with a significant impact over the immune response during autoimmunity, skewing it to a pathogenic state, promoting both Th1 and Th17 commitment. It seems comprehensible that the specificity and primary function of Hsp60 molecules can be considered as a potential pathogenic factor acting as a whistleblower announcing chronic-inflammatory diseases progression.

Appraisal and management of subclinical choroidal inflammation: the iceberg phenomenon

Abstract Purpose To explore further the ocular fundal structures after funduscopy has been performed in intraocular inflammatory diseases, we have at our disposal among other investigational imaging methods, fluorescence angiography comprising fluorescein angiography (FA) and indocyanine green angiography (ICGA). In most cases dual FA &amp; ICGA is necessary as the two methods image completely different structures. Fluorescein angiography is giving information on superficial structures including the optic disc, the retinal vessels and the retina as well as on the RPE, whereas ICGA is exploring the choroidal compartment. In contrast to FA that usually does not furnish additional information but is only giving more precise images of the superficial structures explored, ICGA is revealing elements, in case of choroidal inflammatory involvement, that no other method can show. The choroidal inflammatory lesions can be very extensive while often causing only faint or no signs during clinical examination and with other investigational imaging methods, a phenomenon which corresponds to the so‐called “iceberg effect”. This aptitude of ICGA to show lesions that are otherwise inaccessible make it an essential method to detect and follow choroidal lesions. Methods Cases where diagnosis cannot be made without ICGA or cases where inflammation can only be followeb by ICGA, the so‐called iceberg constellation because other methods show only faint or no signs, will be presented. Conclusion Inflammatory lesions limited to the choroid cannot be detected without performing ICGA which is indispensible to diagnose purely choroidal diseae and to monitor the evolution of choroidal inflammation.