The level of thymic expression of RPE65 inversely correlates with its capacity to induce experimental autoimmune uveitis (EAU) in different rodent strains

We have previously shown that immunization with RPE65 produces in rats of four strains a severe inflammatory eye disease, designated experimental autoimmune uveitis (EAU). Here, we examined the uveitogenicity of RPE65 in six strains of mice. Only one strain, C57Bl/6, was found to develop consistently moderate levels of EAU, whereas other strains (BALB/c, B10.A, B10.BR, B10.RIII, C57BL/10J) were found to be essentially resistant to disease induced by RPE65. Analysis of the expression of RPE65 mRNA in thymi of the six mouse strains revealed detectable levels of the transcript in all strains, but with remarkable quantitative differences, with the lowest levels seen in thymi of C57Bl/6 mice, the only strain susceptible to RPE65-induced EAU. Moreover, unlike the finding with the mice, no RPE65 mRNA was detected in thymi of any of the four rat strains (Lewis, BN, F344, SHR) all of which are susceptible to the disease. These data thus indicate that the susceptibility to RPE65-induced EAU is inversely related to the thymic expression of the molecule. The data also suggest that this disease can be induced only in mice in which thymic expression of RPE65 is sufficiently low to allow the escape from deletion of T-cells with the adequate capacity to initiate the pathogenic immune response.

Identification of crystallin family proteins in vitreous body in rat endotoxin-induced uveitis: Involvement of crystallin truncation in uveitis pathogenesis

Endotoxin-induced uveitis (EIU) is an animal model of acute ocular inflammation. To characterize the mechanism of EIU, we analyzed the infiltration of proteins in the vitreous bodies of rats with EIU and normal rats using 2-DE and micro LC/LC-MS/MS. Twenty spots were identified in vitreous bodies of rats. Eighteen of these spots were members of the crystallin family. The truncated form of beta A4- and beta B2-crystallin were predominant in normal vitreous bodies, but there were intact form of crystallins in lipopolysaccharide-injected rats with EIU. These results suggest that crystallin family proteins are the major group of proteins involved in uveitic vitreous and that C-terminal truncation of beta-crystallins may play a role in EIU-related disease progression.

Mechanisms for inducing nasal mucosal tolerance in experimental autoimmune uveoretinitis

Delivering soluble (auto) antigenic peptides via the naso-respiratory route induces tolerance to that peptide and suppression of experimental models of autoimmune disease. In the normal lung, respiratory tract dendritic cells (RTDCs) efficiently endocytose soluble antigens, migrate to regional lymph nodes and present peptide to T cells that subsequently become tolerant. This article describes protocols for inducing tolerance via the naso-respiratory tract in experimental autoimmune uveoretinitis (EAU); for the isolation of RTDCs to facilitate definition of, and conditions for, maturation and activation of cells; and to test RTDC ability to induce tolerance in murine EAU when adoptively transferred.

Induction of suppressors of cytokine signaling (SOCS) in the retina during experimental autoimmune uveitis (EAU): potential neuroprotective role of SOCS proteins

Suppressors of cytokine signaling (SOCS) are implicated in immunopathogenic mechanisms of autoimmune diseases. We show here that SOCS expression in retina is temporarily correlated with progression of experimental autoimmune uveitis (EAU), an organ-specific autoimmune disease that serves as model of human uveitis. Peak of EAU correlates with highest SOCS genes expression while disease resolution coincides with their down-regulation. Surprisingly, SOCS5 is constitutively expressed in retina. SOCS5 expression increases significantly during EAU and remains elevated even after disease resolution. Our data suggest that cytokine-inducible SOCS members may be involved in negative regulation of inflammatory cytokines activities during EAU, while constitutively expressed SOCS5 may have neuroprotective functions.

Pigment epithelium‐derived factor (PEDF) is an endogenous antiinflammatory factor

Pigment epithelium-derived factor (PEDF) is a potent angiogenic inhibitor. Reduced PEDF levels are associated with diabetic retinopathy. However, the mechanism for the protective effects of PEDF against diabetic retinopathy (DR) is presently unclear. As inflammation plays a role in DR, the present study determined the effect of PEDF on inflammation. Western blot analysis and ELISA demonstrated that retinal and plasma PEDF levels were drastically decreased in rats with endotoxin-induced uveitis (EIU), which suggests that PEDF is a negative acute-phase protein. Intravitreal injection of PEDF significantly reduced vascular hyper-permeability in rat models of diabetes and oxygen-induced retinopathy, correlating with the decreased levels of retinal inflammatory factors, including VEGF, VEGF receptor-2, MCP-1, TNF-alpha, and ICAM-1. In cultured retinal capillary endothelial cells, PEDF significantly decreased TNF-alpha and ICAM-1 expression under hypoxia. Moreover, down-regulation of PEDF expression by siRNA resulted in significantly increases of VEGF and TNF-alpha secretion in retinal Müller cells. These findings suggest that PEDF is a novel endogenous anti-inflammatory factor in the eye. The decrease of ocular PEDF levels may contribute to inflammation and vascular leakage in DR.

Effects of intraperitoneal vitamin E, melatonin and aprotinin on leptin expression in the guinea pig eye during experimental uveitis

PURPOSE

To observe ultrastructural changes and leptin expression in the guinea pig eye during experimental uveitis (EU) and the effects of vitamin E, melatonin and aprotinin on leptin expression.

METHODS

Thirty male guinea pigs were randomly classified into five groups. Group 1 was the control group. Groups 2, 3, 4 and 5 received intravitreal injections of bovine serum albumin (BSA) to induce EU. At the same time on the third day, groups 3 (EU + vitamin E), 4 (EU + melatonin) and 5 (EU + aprotinin) received intraperitoneal vitamin E (150 mg/kg), melatonin (10 mg/kg) and aprotinin (20,000 IU/kg), respectively. On the sixth day, histopathological and clinical scoring of inflammation were performed, and leptin expression was investigated in the retina, choroid, sclera, episclera and cornea, and compared.

RESULTS

There was a remarkable increase in leptin expression in the retina, choroid, sclera and episclera in the EU group. Leptin expression in the treatment groups was similar to that in the control group. At light and electron microscopic levels, ganglion cells were oedematous and inner plexiform layer thickness had increased in the EU group retinas. Oedema was decreased in the treatment groups. Comparison of the EU and treatment groups revealed significant differences histopathologically and clinically.

CONCLUSION

Experimental uveitis causes an increase in leptin expression in the retina, choroid, sclera and episclera of guinea pigs. Vitamin E, melatonin and aprotinin inhibit this increase. Leptin seems to be closely related to ocular inflammation.

Endotoxin-Induced Uveitis Causes Long-Term Changes in Trigeminal Subnucleus Caudalis Neurons

Endotoxin-induced uveitis (EIU) is commonly used in animals to mimic ocular inflammation in humans. Although the peripheral aspects of EIU have been well studied, little is known of the central neural effects of anterior eye inflammation. EIU was induced in male rats by endotoxin or lipopolysaccharide (LPS, 1 mg/kg ip) given 2 or 7 days earlier. Neurons responsive to mechanical stimulation of the ocular surface were recorded under barbiturate anesthesia at the trigeminal subnucleus interpolaris/caudalis (Vi/Vc) transition and subnucleus caudalis/cervical cord (Vc/C1) junction, the main terminal regions for corneal nociceptors. Two days after LPS, Vc/C1 units had reduced responses to histamine, nicotine, and CO2 gas applied to the ocular surface, whereas unit responses were increased 7 days after LPS. Those units with convergent cutaneous receptive fields at Vc/C1 were enlarged 7 days after LPS. Units at the Vi/Vc transition also had reduced responses to histamine and CO2 2 days after LPS but no enhancement was seen at 7 days. Tear volume evoked by CO2 was reduced 2 days after LPS and returned toward control values by 7 days, whereas CO2-evoked eye blinks were normal at 2 days and increased 7 days after LPS. These results indicate that a single exposure to endotoxin causes long-term changes in the excitability of second-order neurons responsive to noxious ocular stimulation. The differential effects of EIU on tear volume and eye blink lend further support for the hypothesis that ocular-sensitive neurons at the Vi/Vc transition and Vc/C1 junction regions mediate different aspects of pain during intraocular inflammation.

Effects of blue honeysuckle (Lonicera caerulea L.) extract on lipopolysaccharide-induced inflammation in vitro and in vivo

The aim of the present study was to investigate the effects of blue honeysuckle extract (BHE), which contains high level of phenolic compounds, on endotoxin-induced uveitis (EIU). Male Lewis rats were randomly divided into 5 groups with 14 rats in each (eight rats for collection of aqueous humor, six rats for histologic examination). EIU was induced by a footpad injection of lipopolysaccharide (LPS). 1, 10, or 100 mg of BHE was injected intravenously immediately after LPS injection. The aqueous humor was collected at 24 h after LPS injection, the number of infiltrating cells, protein concentration, nitric oxide (NO), tumor necrosis factor (TNF)-alpha, and prostaglandin (PG)-E2 levels in the aqueous humor were determined. Some eyes were enucleated for histologic examination and immunohistochemical analysis. Immunohistochemical staining with a monoclonal antibody against activated nuclear factor (NF)-kappaB was performed to evaluate the effect of BHE on NF-kappaB activation. To further clarify the anti-inflammatory effect, RAW264.7 cells (a mouse macrophage cell line) were stimulated with LPS in the presence or absence of BHE and its major phenolics, cyanidin 3-glucoside (C3G), cyanidin 3-rutinoside (C3R), chlorogenic acid (CA). Expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) were analyzed by Western blot method. BHE treatment significantly reduced the inflammatory cell infiltration, the protein concentration, the levels of NO, TNF-alpha and PGE2 in the aqueous humor and improved histologic status of the ocular tissue. The number of activated NF-kappaB-positive cells was lower in the iris-ciliary body treated with BHE at 3 h after LPS injection. BHE significantly suppressed the production of NO, PGE2 and TNF-alpha in the culture medium as well as the expression of iNOS and COX-2 by LPS-stimulated RAW264.7 cells in a dose-dependent fashion. C3G, C3R and CA showed no or weak inhibitory effects on the level of inflammatory mediators and the expression of iNOS and COX-2. These results suggest that BHE attenuates the degree of inflammation in eyes with EIU by inhibiting the NF-kappaB dependent signaling pathway and the subsequent production of proinflammatory mediators.

Tetracycline-inducible viral interleukin-10 intraocular gene transfer, using adeno-associated virus in experimental autoimmune uveoretinitis

Members of the adeno-associated virus (AAV) family are good candidates for the treatment of ocular diseases because of their relative lack of pathogenicity. We studied the effect of intraocular injection of AAV2-viral IL-10 (vIL-10) on retinal S-antigen-induced experimental autoimmune uveoretinitis (EAU) in Lewis rats. We demonstrated that AAV2/2-GFP injected into the vitreous body transduced the iris and ciliary body, or anterior uvea, and the retina. We showed that intravitreal injection of the AAV2/2-tetON-vIL-10 construct achieved detectable levels of vIL-10 mRNA and protein within the eye and was effective in protecting the rat retina against destruction. This protection was dependent on the level of vIL-10 present in the aqueous humor/ vitreous body. Intravitreal injection of the same construct encased within an AAV5 shell, AAV2/5-tetONvIL- 10, did not confer any degree of protection. It appeared that the AAV2/5 vectors did not transduce the anterior uvea, the site at which inflammatory cells first localize in EAU, nor the ganglion cell layer; induced low expression of vIL-10 mRNA; and did not achieve detectable levels of transgene expression in the aqueous humor/vitreous body. Local treatment with AAV2/2-tetON-vIL-10 did not dampen the systemic immune response, as determined by S-antigen-specific lymphocyte proliferation. Our results show that local intravitreal injection of AAV2/2 is an effective means by which to deliver immunoregulatory molecules into the eye during uveitis, a chronic human ocular disease.

Rifabutin-associated uveitis in a child

Uveitis associated with rifabutin treatment is a well-known adverse effect in adults with human immunodeficiency virus infection. In children, however, uveitis related to rifabutin has been reported in only a few cases. We present a case of rifabutin-associated uveitis in a human immunodeficiency virus-negative child. We review the literature and discuss special precautions to be considered when children are treated with rifabutin.

Transthyretin synthesis in rabbit ciliary pigment epithelium

Ocular symptoms of transthyretin (TTR)-related familial amyloidotic polyneuropathy (FAP) suggest that ciliary pigment epithelium (CPE) may synthesize TTR and its TTR may lead to amyloid formation in addition to TTR from vessels and retinal pigment epithelium (RPE). To clarify sites of TTR synthesis in ocular tissues, we performed in situ hybridization and reverse transcription-polymerase chain reaction (RT-PCR) for qualitative detection of TTR mRNA. In addition, we quantified levels of TTR mRNA expression by means of real-time quantitative RT-PCR. Furthermore, although TTR is an anti-acute phase protein in serum level, no reports on changes in TTR expression in ocular tissues during acute inflammation exist. To investigate changes in TTR expression in ocular tissues during inflammation, we induced uveitis by endotoxin challenge in rabbits and used real-time quantitative RT-PCR to examine changes in TTR mRNA expression in ocular tissues. In situ hybridization and RT-PCR qualitatively demonstrated TTR mRNA not only in RPE but also in CPE. Real-time quantitative RT-PCR showed that the level of TTR mRNA expression in the CPE was about one-third of that in the RPE. TTR mRNA expression in ocular tissues decreased as the degree of inflammation increased. These results suggest that TTR synthesized in the CPE may lead to ocular manifestations, especially glaucoma, in FAP. TTR mRNA also acts as an anti-acute phase reactant in ocular tissues.

CCR5-Deficient Mice Develop Experimental Autoimmune Uveoretinitis in the Context of a Deviant Effector Response

PURPOSE

Experimental autoimmune uveoretinitis (EAU) is an organ-specific, Th1-cell-mediated disease that targets the neural retina. CCR5 is a chemokine receptor expressed on Th1 cells that promotes their migration. In CCR5-deficient mice, we examined the role of CCR5 in the development of EAU induced by immunization with interphotoreceptor retinoid-binding protein (IRBP) peptide.

METHODS

Wild-type or CCR5-deficient B6 mice were immunized with human IRBP peptide 1-20 (hIRBP-p), and the severity of EAU was assessed clinically and histologically. Splenocytes and cells of regional lymph nodes near the eye were collected and their proliferation and production of IL-6, IL-10, IFN-gamma, and CCL2 (MCP-1) in response to hIRBP-p stimulation were measured. Moreover, the intraocular levels of these cytokines were analyzed.

RESULTS

Immunization with hIRBP-p induced EAU in CCR5-deficient mice with a severity comparable to that in wild-type mice. Histologically, T-cell infiltration of the eye was reduced, but granulocyte infiltration was augmented in CCR5-deficient mice. Although splenic T cells from CCR5-deficient mice produced IFN-gamma but not IL-10 on stimulation by hIRBP-p, T cells from the regional lymph nodes failed to produce both cytokines. IL-6 production in the eye and IL-6 and CCL2 production by splenic T cells were predominantly augmented in CCR5-deficient mice.

CONCLUSIONS

The development of EAU is not prevented in CCR5-deficient mice. Although T-cell infiltration into the eye is apparently reduced in CCR5-deficient mice, the defect is compensated for by granulocyte infiltration, supposedly mediated by augmented intraocular production of IL-6.

Immunostimulatory and immunomodulatory peptides derived from the alpha1 domain of HLA-B27 in experimental autoimmune diseases in Lewis rats

Peptides derived from amino acid sequence 60-80 of HLA-B27 (B27PA, aa 60-72 and B2702PA, aa 60-80) mimic cytokeratin and are able to induce in vitro proliferation of human peripheral blood lymphocytes as well as arthritis in Lewis rats. Here we show that the pathogenic epitope recognized by autoaggressive rat T cells is located at the N-terminus of the sequence, between aa 60 and 72. A C-terminally elongated 25mer peptide (B2702.60-84) showed increased pathogenicity, indicating either a second arthritogenic epitope or an immunomodulatory region within this peptide. B2702.60-84 has been described to inhibit murine and human CD8 + cytotoxic T cells (CTL) and was even successfully used for the treatment of allograft rejection. In addition to pathogenicity we have investigated the immunomodulatory effect of peptide B2702.60-84 in our rat model of experimental autoimmune uveitis (EAU), induced with retinal S-Antigen peptide PDSAg. We found that disease exacerbated following coimmunization of PDSAg with B2702.60-84. In vitro, the B27-peptide enhanced the proliferation of CD4+ T cell lines specific for retinal autoantigen peptides during coincubation of B2702.60-84 with the respective antigen. Oral tolerance induction, an effective mechanism to prevent uveitis in Lewis rats, is abrogated by cofeeding peptide B2702.60-84 with the tolerogen PDSAg. In rat EAU, naturally occurring regulatory T cells and orally induced gamma deltaTCR+ suppressor cells are CD8+ which might be impeded by peptide B2702.60-84. As a consequence of their abrogated suppressive capacity disease was exacerbated. We propose a similar role of HLA-B27 in man: disturbing the mechanisms down-regulating self-responses might lead to autoimmune diseases. This could explain the high association of HLA-B27 with a variety of autoimmune diseases targeting different organs or tissues.

Photoreceptor mitochondrial tyrosine nitration in experimental uveitis

PURPOSE

In experimental autoimmune uveitis (EAU), phagocytes are thought to be the primary cells in the initiation and maintenance of pathologic tissue damage through the release of cytotoxic agents. Recently, the presence of nitric oxide synthase has been shown in mammalian mitochondria. In this study, the effect of mitochondrial peroxynitrite on the modification of cellular proteins was evaluated in the early phase of uveitis, before the infiltration of leukocytes.

METHODS

Tyrosine nitration in proteins was detected by UV/Vis (visible) absorption and Western blot analysis. The identity of the nitrated protein was obtained by liquid chromatography-tandem mass spectrometry. The release of cytochrome c was assessed in whole retinal extract and in isolated mitochondria. The protein nitration in the inflamed retina was also localized by immunohistochemistry.

RESULTS

Before the leukocyte infiltration in the early phase of EAU, the mitochondria-originated peroxynitrite initiated the inflammatory insult by specifically nitrating three mitochondrial proteins. In vitro nitration of the control retina by peroxynitrite donor resulted in nonspecific nitration of all major retinal proteins. After nitration, cytochrome c was displaced from its original binding site in the respiratory chain. Further, the nitration appeared to commence in the early phase of inflammation, on postimmunization day 5, long before the peak of inflammation on day 14. Immunohistochemically, tyrosine-nitrated proteins were localized exclusively in the photoreceptor inner segments, which are known to be densely populated with mitochondria.

CONCLUSIONS

These data indicate that mitochondrial proteins are the prime targets of inactivation by the mitochondrial peroxynitrite and that photoreceptor mitochondria initiate the subsequent irreversible retinal damage in experimental uveitis.

Leukocyte diapedesis in vivo induces transient loss of tight junction protein at the blood-retina barrier

PURPOSE

Although much is now understood about the molecular structure of tight junctions (TJs), little is known about the regulation of their function during neural inflammatory disease processes in vivo. The mechanisms by which leukocytes transmigrate the blood-retina barrier (BRB) without affecting endothelial permeability are controversial.

METHODS

Confocal immunofluorescence microscopy of ex vivo retinal wholemounts was used to study BRB integrity during leukocyte adhesion and migration during experimental autoimmune uveoretinitis (EAU). Western blot analysis was used to measure levels of TJ proteins in EAU retina and RPE and in normal retina or RPE cultured with cytokines or chemokines.

RESULTS

No evidence for discontinuity or other weakness of the endothelial or epithelial barrier at tricellular corners was observed, and maximum disruption of TJ protein expression was focused in retinal venules correlating with sites of leukocyte extravasation. Areas of maximum TJ protein loss in vivo also correlated with redistribution or loss of ensheathing astrocyte processes on venules but not adjacent capillaries or arterioles. Exposure of normal choroidal and retinal explants ex vivo to cytokines and chemokines alone did not downregulate total occludin-1 or claudin-3 TJ protein expression.

CONCLUSIONS

The data presented herein support an active role for leukocytes in TJ disruption and blood-retina barrier (BRB) breakdown during retinal inflammation and further implicate venule microenvironment as a key factor in leukocyte recruitment to retinal tissue in vivo.

Suppression of Ocular Inflammation in Endotoxin-Induced Uveitis by Blocking the Angiotensin II Type 1 Receptor

PURPOSE

To examine whether the angiotensin II type 1 receptor (AT1-R) signaling plays a role in ocular inflammation in endotoxin-induced uveitis (EIU).

METHODS

EIU was induced in C57BL/6 mice by a single intraperitoneal injection of 150 mug lipopolysaccharide (LPS). Tissue localization, mRNA expression, and protein levels of AT1-R in murine retinas were examined by immunohistochemistry, RT-PCR, and Western blot analyses, respectively. Telmisartan, an AT1-R antagonist widely used as an antihypertensive agent, was administered intraperitoneally at a dose of 10 mg/kg daily for 5 days until the injection of LPS. Twenty-four hours after administration, leukocyte adhesion to the retinal vasculature was evaluated with a concanavalin A lectin perfusion-labeling technique. Retinal mRNA and protein levels of intercellular adhesion molecule (ICAM)-1 were examined by RT-PCR and ELISA, respectively. Protein concentration and inflammatory cells in the aqueous humor were also measured.

RESULTS

Retinal vessels were positive for AT1-R. In mice with EIU, retinal AT1-R mRNA and protein levels were significantly increased when compared to the normal control. EIU animals also showed significant increases in the number of inflammatory cells infiltrating the anterior chamber and adhering to the retinal vessels and in retinal ICAM-1 levels. Administration of telmisartan to EIU mice resulted in significant suppression of retinal ICAM-1 expression and leukocyte adhesion and infiltration compared with vehicle treatment. Protein concentration in the aqueous humor of telmisartan-treated EIU mice tended to be lower than that of vehicle-treated EIU mice, but the difference was not statistically significant.

CONCLUSIONS

AT1-R signaling blockade inhibited retinal ICAM-1 upregulation and leukocyte adhesion and infiltration in the EIU model. These results suggest the potential use of an AT1-R antagonist as a therapeutic agent to reduce ocular inflammation.

[Acute and bilateral uveitis secondary to moxifloxacin]

CASE REPORT

We report a case of a 77-year-old woman with an anterior acute bilateral uveitis and pigmentary dispersion after treatment of a neumococic pneumonia with moxifloxacin. Her response to treatment was good but she presented as a result of treatment abundance of pigment over all the structures of the anterior segment.

DISCUSSION

Many drugs can produce uveitis. After Med-line revision, we can not find any previously reported case of anterior Uveitis associated with fourth generation quinolones.

Anti-inflammatory effects of alpha-melanocyte-stimulating hormone against rat endotoxin-induced uveitis and the time course of inflammatory agents in aqueous humor

PURPOSE

We examined the effects of the immunosuppressive neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH) on rat endotoxin-induced uveitis, and to measure the expression of inflammatory cytokines and chemokines with and without the alpha-MSH treatment over the course of the disease.

METHODS

We injected Lewis rats once with Salmonella typhimurium lipopolysaccharide (LPS) to induce uveitis. The rats were given intravenous injections of 250, 500 or 1000 microg of alpha-MSH. The eyes were examined over the next 24 h for inflammation. Aqueous humor was collected 6, 12 and 24 h after endotoxin injections and the number of infiltrating cells were counted in anterior chamber. In addition, we assayed the concentration of protein, nitric oxide, TNF-alpha, IL-6, MCP-1 and MIP-2.

RESULTS

Rats injected with alpha-MSH showed a significant decrease in the number of infiltrating cells in anterior chamber. Moreover, alpha-MSH-treated rats with endotoxin-induced uveitis (EIU) showed significantly lower concentrations of protein, nitric oxide, proinflammatory cytokines and chemokines in their aqueous humor. Even the early stages of EIU were suppressed by the injection of alpha-MSH.

CONCLUSIONS

Our results demonstrate that the immunosuppressive neuropeptide alpha-MSH inhibits the early induction events of endotoxin-induced inflammation in the eye; therefore, suppresses the subsequent infiltration of cells and intraocular production of inflammatory cytokines and chemokines in eyes. alpha-MSH has a possibility of being a therapeutic strategy for anterior uveitis.

The effect of the CC chemokine receptor antagonist Met-RANTES on experimental autoimmune uveitis and oral tolerance

Lymphocyte trafficking is controlled in part by the actions of chemokines. In rat experimental autoimmune uveitis (EAU) we observed differential therapeutic effects of Met-RANTES, a CCR1/CCR5 receptor antagonist, depending on the retinal antigen peptides inducing the disease and the time of application during the afferent or efferent immune response. CCR1 and/or CCR5 blockade may have inhibitory effects on different phases of the autoimmune response, depending on the antigen specificity of T cells in EAU. In contrast, Met-RANTES enhanced therapeutic oral tolerance independently of orally applied antigen.

Systemic interferon-gamma suppresses the development of endotoxin-induced uveitis in mice

PURPOSE

It has been shown that interferon (IFN)-gamma is involved in the development of endotoxin-induced uveitis (EIU), but its exact role is unclear. We aimed to elucidate the role that endogenous systemic IFN-gamma plays in EIU pathogenesis.

METHODS

EIU was induced in wild-type (WT) or IFN-gamma knockout (GKO) mice on the C57BL/6 background by injecting Salmonella typhimurium endotoxin into a hind footpad. Twenty-four hours later, the eyes were harvested for histological analysis, and the serum was collected for cytokine ELISAs. WT and GKO mice were also intraperitoneally injected with 1 microg of recombinant murine IFN-gamma (rmIFN-gamma) just after and 6 h after EIU induction, and their eyes and sera were evaluated 24 h after EIU induction, as above.

RESULTS

The GKO mice had significantly more severe EIU as determined by the number of ocular infiltrating cells and lower serum IL-6 levels after EIU induction compared to WT mice. The injection of rmIFN-gamma suppressed the severity of EIU and increased the serum IL-6 levels in both the WT and GKO mice.

CONCLUSIONS

Endogenous IFN-gamma suppresses EIU pathogenesis. In addition, the systemic administration of IFN-gamma suppresses EIU. The suppressive mechanism involved is unclear but may relate to the production of IL-6.

Effects of intravitreal injection of tacrolimus (FK506) in experimental uveitis

PURPOSE

To examine the immunosuppressive and neuroprotective effects of intravitreal injection of tacrolimus in experimental uveitis.

METHODS

Tacrolimus (40 microg) was injected intravitreally in rabbits to examine safety. Experimental uveitis was induced in rabbits by systemic immunization with bovine serum albumin (BSA) followed by intravitreal challenge with BSA. On day 1 after BSA challenge, tacrolimus (20 or 40 microg) or betamethasone (400 microg) was injected intravitreally in one eye and balanced salt solution in the contralateral eye. The eyes were evaluated by slit-lamp biomicroscopy, electroretinography, and histopathology.

RESULTS

No local or systemic adverse reaction was observed in normal rabbits. In experimental uveitis, intravitreal injection of tacrolimus significantly reduced intraocular inflammation in histopathological analysis (p < 0.03). Amplitudes on the electroretinogram were restored (p < 0.01), and retinal thickness was preserved in tacrolimus-treated eyes (p < 0.03).

CONCLUSIONS

In experimental uveitis, intravitreal injection of tacrolimus effectively suppresses ocular inflammation and preserves retinal architecture.

Ibandronate (Boniva): a new oral bisphosphonate

In a 3-year study with 2.5 mg of ibandronate daily in postmenopausal women with at least 1 pre-existing vertebral fracture, the drug reduced new vertebral fractures by 50%, but had no effect on non-vertebral fractures. The 150-mg once-monthly formulation of ibandronate was as effective as the daily one in increasing bone mineral density and decreasing bone turnover markers. It appears to be similar to alendronate and risedronate in efficacy and tolerability, but head-to-head comparisons are lacking.

Lesions caused by ricin applied to rabbit eyes

PURPOSE

Ricin, a highly potent toxin from castor beans, is a potential biological weapon that could be dispersed in the air as dust or aerosol. In these forms, ricin, besides being inhaled, could reach unprotected eyes. The present research was performed to ascertain the lesions that the toxin causes when applied to rabbit eyes.

METHODS

Ricin was applied to rabbit eyes in solution, in quantities ranging from 1 to 100 mug. Animals were observed until death, when eyes and internal organs were removed and fixed. Sections were stained and examined microscopically.

RESULTS

Ricin caused inflammation of the eyes and adnexa, visible both macroscopically and histologically. The damage was greatly reduced by rinsing the eyes with 10% lactose, provided the rinsing was done almost immediately after application of the toxin. Rinsing with phosphate-buffered saline (PBS) had no effect. With the highest dosage, congestion of internal organs was also apparent.

CONCLUSIONS

Application of ricin to eyes causes local damage, mainly of the inflammatory type. The ineffectiveness of rapid rinsing with PBS and the partial efficacy of rapid rinsing with lactose indicate that the toxin quickly binds to and is taken up by cells. The lesions of internal organs show that ricin applied to the eyes can be absorbed, pass into the circulation, and, at least at some dosages, damage internal organs.