Amelioration of experimental autoimmune uveoretinitis by inhibition of glyceraldehyde-derived advanced glycation end-product formation.

AGEs are permanently modified macromolecule derivatives that form through nonenzymatic glycation of amino groups of proteins. Glycer-AGEs are highly toxic and play an important role in the pathogenesis of chronic inflammatory diseases. However, the contribution of glycer-AGEs to the pathogenesis of uveitis is unclear. In this study, we measured serum levels of glycer-AGEs in 100 patients with endogenous uveitis (22 with HLA-B27-associated uveitis, 20 with VKH disease, 14 with Behçet's disease, and 44 with sarcoidosis) and 33 healthy volunteers. We then examined the effect of the AGE inhibitor in a mouse model of human endogenous uveitis (EAU) by continuous oral administration of pyridoxamine at 200 or 400 mg/kg/day. Regardless of the etiology, serum glycer-AGE levels were significantly higher in patients with uveitis than in healthy subjects. Treatment with 400 mg/kg pyridoxamine significantly reduced the clinical and histological severity of EAU and was accompanied by a significant decrease in serum and retinal glycer-AGE levels and suppression of translocation of NF-κB p65 into the nucleus of retinal cells. Serum glycer-AGE levels may therefore serve as a biomarker of human uveitis, as well as systemic inflammation, and may contribute to the progression of uveitis, including diabetic iritis, via the activation of NF-κB.

Is inflammation a common retinal-renal-nerve pathogenic link in diabetes?

The global diabetes burden is predicted to rise to 380 million by 2025 and would present itself as a major health challenge. However, both Type 1 and Type 2 diabetes increase the risk of developing micro-vascular complications and macro-vascular complications which in turn will have a devastating impact on quality of life of the patients and challenge health services Worldwide. The micro-vascular complications that affect small blood vessels are the leading cause of blindness (diabetic retinopathy) in the people of the working-age, end-stage renal disease (diabetic nephropathy) the most common cause of kidney failure today, and foot amputation (diabetic neuropathy) in patients with Type 1 and Type 2 diabetes. It is accepted that hyperglycemia is a major causative factor for the development of these complications, there is also growing evidence for the role of inflammation. Here we discuss low-grade inflammation as a common retinal-renal-nerve pathogenic link in patients with Type 1 and Type 2 diabetes. This review summarizes evidence showing a link between circulating and locally produced inflammatory biomarkers, such as cell adhesion molecules (vascular adhesion cell molecule-1, VCAM-1; intracellular adhesion molecule-1, ICAM-1), pro-inflammatory cytokines (interleukin-6, IL-6; tumour necrosis factor-alpha, TNF-α; C-reactive protein, CRP) with the development and progression of diabetic micro-vascular complications.

Prevention of experimental autoimmune uveoretinitis by blockade of osteopontin with small interfering RNA.

Osteopontin (OPN) is elevated during the progression of experimental autoimmune uveoretinitis (EAU) in C57BL/6 (B6) mice. Furthermore, EAU symptoms are ameliorated in OPN knockout mice or in B6 mice treated with anti-OPN antibody (M5). Recently, OPN has been shown to promote the Th1 response not only in the extracellular space as a secretory protein but also in cytosol as a signaling component. Thus, we attempted to reduce OPN in both compartments by using a small interfering RNA (siRNA) targeting the OPN coding sequence (OPN-siRNA). EAU was induced in B6 mice by immunization with human interphotoreceptor retinoid-binding protein (hIRBP) peptide sequence 1-20. The OPN- or control-siRNA was administered with hydrodynamic methods 24 h before and simultaneously with immunization (prevention regimen). When plasma OPN levels were quantified following siRNA administration with the prevention regimen, the level in the OPN-siRNA-treated group was significantly lower than that in the control-siRNA-treated group. Accordingly, the clinical and histopathological scores of EAU were significantly reduced in B6 mice when siRNA caused OPN blockade. Furthermore, TNF-alpha, IFN-gamma, IL-2, GM-CSF and IL-17 levels in the culture supernatants were markedly suppressed in the OPN-siRNA-treated group, whereas the proliferative responses of T lymphocytes from regional lymph nodes against immunogenic peptides was not significantly reduced. On the other hand, the protection was not significant if the mice received the OPN-siRNA treatment on day 7 and day 8 after immunization when the clinical symptoms appeared overt (reversal regimen). Our results suggest that OPN blockade with OPN-siRNA can be an alternative choice for the usage of anti-OPN antibody and controlling uveoretinitis in the preventive regimen.

Critical but divergent roles for CD62L and CD44 in directing blood monocyte trafficking in vivo during inflammation.

Using noninvasive in vivo imaging and experimental autoimmune uveoretinitis as a model, we show for the first time that the mechanisms controlling blood monocyte recirculation through peripheral and lymphoid tissues alter during inflammation. The recirculation of monocytes in mice with ocular inflammation but not controls was found to depend on the selectin CD62-ligand (CD62L) and on CD44. Not only was rolling efficiency ablated or markedly reduced in antibody-treated mice, but most of the labeled monocytes also disappeared from the circulation within seconds, anti-CD44-treated monocytes homing to the lymph nodes and anti-CD62L-treated monocytes homing to the spleen. Our data indicate that, although PSGL-1 has a partial role in the transmigration of monocytes into the inflamed retina, CD62L has a key role in regulating recruitment of monocytes to lymphoid tissue from the blood during inflammation and that CD44 is required to maintain CD62L(+) inflammatory monocytes within the circulation during inflammation. This effect was systemic, because sequestered monocytes accumulated in mesenteric as well as draining cervical lymph nodes, and inflammation dependent, because depletion of circulating blood monocytes was much reduced or absent in normal mice and accumulations of adoptively transferred monocytes in the lymphoid tissues did not occur.

Serum inflammatory markers in diabetic retinopathy.

PURPOSE: To evaluate the association of serum factors with the severity of diabetic retinopathy and to assess their presence in retinal tissue obtained at autopsy. METHODS: The following serum factors of 93 subjects were examined at the National Eye Institute (NEI) clinical center: the chemokines regulated on activation, normal T-cell expressed and presumably secreted (RANTES)/CCL5, epithelial neutrophil activator (ENA)-78/CXCL5, interferon-induced protein (IP)-10/CXCL10, stromal cell-derived factor (SDF)-1alpha/CXCLl2, monocyte chemoattractant protein (MCP)-1/CCL2, macrophage inflammatory protein (MIP)-1alpha/CCL3, interleukin (IL)-8/CXCL8; the cytokine IL-6; the cell adhesion molecules intercellular adhesion molecule (ICAM-1/CD54) and vascular cell adhesion molecule (VCAM/CD106); and the growth factor vascular endothelial growth factor (VEGF). Logistic regression was performed to assess the association of these factors with age, sex, severity of retinopathy, hemoglobin A(1C), total cholesterol, creatinine, duration of diabetes, and presence of macular edema. The outcome assessed was severity of retinopathy. Frozen sections of two donor eyes obtained at autopsy from a donor with documented severe nonproliferative diabetic retinopathy and diabetic macular edema and of a normal nondiabetic eye were processed by immunoperoxidase staining with primary antibodies against RANTES, MCP-1, ICAM-1, and LFA-1alpha/CD11a. RESULTS: The levels of RANTES and SDF-1alpha were significantly elevated in patients with at least severe nonproliferative diabetic retinopathy compared with those with less severe diabetic retinopathy (P < 0.001 and 0.007, respectively). Positive immunostaining was observed in the inner retina for MCP-1 and RANTES of the patient with diabetes. Staining was strongly positive throughout the diabetic retina for ICAM-1. Normal retinal tissues showed little reactivity. CONCLUSIONS: Serum chemokines were significantly elevated in patients with at least severe nonproliferative diabetic retinopathy compared with those who had less severe retinopathy. Elevated levels of the chemokines and cell adhesion molecules were also identified in eyes of a donor with ischemic diabetic retinopathy. These findings provide evidence to support the role of inflammation in the pathogenesis of diabetic retinopathy.

Retinal microangiopathy in human immunodeficiency virus infection is related to higher human immunodeficiency virus-1 load in plasma.

PURPOSE: To evaluate the prevalence of retinal microangiopathy in human immunodeficiency virus (HIV)-1-infected patients and its association with virologic, immunologic, and sociodemographic parameters. DESIGN: Single-center cross-sectional study. PARTICIPANTS: One hundred eighty-eight HIV-1-positive individuals from a single outpatient clinic. METHODS: Human immunodeficiency virus-positive patients were screened for signs of HIV-associated retinal angiopathy. Plasma HIV-1 RNA and CD4-positive cell counts were monitored within 3 months of the ophthalmologic assessment. The absence or presence of angiopathy or of opportunistic viral retinitis was then correlated to data respecting CD4-positive cell count, plasma viral load of HIV-1, and sociodemographic parameters. MAIN OUTCOME MEASURES: Association between CD4-positive cell count, HIV-1 plasma viral load, sociodemographic parameters, and the manifestation of retinal microangiopathy. RESULTS: At the baseline consultation, 130 (69%) patients exhibited no retinal pathologic features, 45 (24%) manifested retinal angiopathy, and 13 (7%) had opportunistic viral retinitis. In univariate analysis, retinal angiopathy was associated with lower CD4-positive cell count and higher HIV-1 plasma viral load. In a multivariate logistic model, the presence of retinal microangiopathy was associated with higher age (P = 0.02) and higher viral load of HIV-1 (P < 0.005), but not with lower CD4 cell counts (P > 0.05). CONCLUSIONS: Human immunodeficiency virus-associated retinal microangiopathy is likely a multifactorial condition. Its presence is associated with higher age and higher replication of HIV-1 as measured by plasma HIV-1 RNA levels. In contrast to opportunistic infectious retinitis, the degree of immunodeficiency does not seem to be independently correlated with retinal angiopathy.

In vitro induction of CD25+ CD4+ regulatory T cells by the neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH).

Recently, we have found that the neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH) not only suppresses IFN-gamma production, but also induces TGF-beta1 production by activated effector T cells. These alpha-MSH- treated effector T cells function as regulatory T cells in that they suppress IFN-gamma production and hypersensitivity mediated by other effector T cells. Experimental autoimmune uveoretinitis (EAU) was suppressed in its severity and incidence in mice that were injected with primed T cells activated in vitro by APC and antigen in the presence of alpha-MSH. Moreover, it appeared that alpha-MSH had converted a population of effector T cells polarized to mediate hypersensitivity into a population of T cells that now mediated immunoregulation. To characterize these alpha-MSH- treated T cells, primed T cells were TCR-stimulated in the presence of alpha-MSH in vitro and their lymphokine profile was examined. Such effector T cells displayed enhanced levels of TGF-beta1 production and no IFN-gamma or IL-10, with IL-4 levels remaining unchanged in comparison with inactivated T cells. In addition, if soluble TGF-beta receptor II was added to cocultures of alpha-MSH-treated T cells and activated Th1 cells, the alpha-MSH-treated T cells could not suppress IFN-gamma production by the Th1 cells. These results suggest that alpha-MSH induces T cells with a regulatory lymphokine pattern, and that through their production of TGF-beta1 these cells suppress other effector T cells. Examination of the alpha-MSH-treated T cells showed that alpha-MSH did not alter the phosphorylation of CD3 molecules following TCR engagement. Primed T cells express the melanocortin 5 receptor (MC5r), a receptor that is linked to an intracellular signalling pathway shared by other cytokine receptors. Blocking the receptor with antibody prevented alpha-MSH from suppressing IFN-gamma production by the activated regulatory T cells, suggesting that alpha-MSH immunoregulation is through the MC5r on primed T cells. Surface staining and cell sorting of the alpha-MSH- treated primed T cells showed that the regulatory T cells are CD25+ CD4+ T cells. From these results we find that alpha-MSH can mediate the induction of CD25+ CD4+ regulatory T cells. These regulatory T cells require specific antigen for activation, but through non-specific TGF-beta1-mediated mechanisms they can suppress other effector T cells.

Experimental autoimmune uveoretinitis in mice (Biozzi ABH and NOD) expressing the autoimmune-associated H-2A(g7) molecule: identification of a uveitogenic epitope.

To determine whether Biozzi ABH (H-2A(g7)) mice were susceptible to chronic experimental autoimmune uveoretinitis (EAU). Biozzi ABH were immunized with the two retinal antigens, interphotoreceptor retinoid binding protein (IRBP) and soluble antigen (S-Ag). Biozzi ABH mice were found to be susceptible to EAU induction with native bovine IRBP. Recombinant protein domains were used to identify IRBP domain 2 (EcR2) as the uveitogenic domain. Histopathological examination indicated that EcR2-induced disease was of a chronic, non-destructive nature in the Biozzi ABH. Using synthetic overlapping peptides corresponding to EcR2, a uveitogenic and immunogenic epitope was identified corresponding to human IRBP511-530. Non-obese diabetic (NOD) mice share the same MHC class II (H-2A(g7)) molecule as the Biozzi ABH, and were also found to be susceptible to EAU induction with EcR2. This study has identified a novel mouse model of EAU, whereby disease is of a chronic, non-destructive nature, which has potential to be used in immune manipulation and neuroprotection studies.

An ocular cat-scratch disease patient positive for cytoplasmic anti-neutrophil cytoplasmic antibody.

BACKGROUND: We report a case of ocular cat-scratch disease with permanent vision reduction in a patient who was cytoplasmic anti-neutrophil cytoplasmic antibody (C-ANCA) positive. METHODS: Case report and review of the literature. RESULTS: While taking steroids and antibiotics, a 52-year-old man with uveitis associated with cat-scratch disease developed retinal vein occlusion and a macular exudate. His final visual acuity was poor because of residual macular degeneration and optic atrophy. Serum C-ANCA increased and decreased in parallel with ocular inflammatory activity. CONCLUSION: C-ANCA is an indicator of vasculitis and may be useful as an indicator of severe cat-scratch disease.

Copolymer 1 inhibits experimental autoimmune uveoretinitis.

Copolymer 1 (Cop 1) inhibits experimental allergic encephalomyelitis induced by a variety of myelin proteins, but has been found ineffective so far in inhibiting other experimental autoimmune diseases such as diabetes or arthritis. Here, we report for the first time that Cop I inhibits the development of experimental autoimmune uveoretinitis, induced in mice by interphotoreceptor retinoid-binding protein (IRBP). Pooled data of three experiments showed that treatment with Cop 1, at 0.5 mg/mouse, reduced the disease severity by 53% ( p = 0.0002). Cop 1 treatment also inhibited the proliferation and the production of cytokines by lymph node cells in response to IRBP and moderately reduced the antibody response to this antigen. The possible mechanisms of EAU inhibition by Cop 1 are discussed.

Low plasma concentrations achieved with conventional schedules of administration of ganciclovir in patients with AIDS.

Plasma concentration of ganciclovir was studied prospectively in 15 AIDS patients treated for acute cytomegalovirus (CMV) retinitis. Ganciclovir was administered at a mean dose of 10.3 +/- 0.6 mg/kg/day. The mean trough plasma concentration was 0.6 +/- 0.3 mg/L (n = 24), and the mean peak concentration was 7.2 +/- 2.4 mg/L (n = 6). In 12 patients, trough concentrations were below the range that has been associated with effective treatment. Low trough concentrations were associated with treatment failure in 6 patients. Following an increase in the daily dose, improvement was observed in 4 of the 6 patients. These results suggest that low plasma ganciclovir levels are associated with the failure of therapy. Monitoring the plasma concentration of ganciclovir may thus be useful before considering the virus to be resistant to the drug or before switching from ganciclovir to foscarnet.

Haematological changes in retinal vasculitis.

Two selected cases of retinal vasculitis, apparently of unknown aetiology, are reported; one case without any systemic or laboratory manifestation and the second case with a clinical picture similar to VKH syndrome and immunodepression. Both cases showed abnormal haematological parameters related to blood viscosity in the early and acute phases which could be manipulated by therapy. Reduction or near normalisation of these haemorrheological parameters coincided with clinical and angiographic improvement. The second case with severe immunodepression was found to be retrovirus HIV-2 positive.

Human pharmacokinetics of the antiviral drug DHPG.

The pharmacokinetics of the antiviral drug 9-[2-hydroxy-1-(hydroxymethyl) ethoxymethyl]guanine (DHPG) were examined in six patients receiving 2.5 or 5.0 mg/kg every 8 or 12 hours for human cytomegalovirus (HCMV) pneumonitis or retinitis. Biexponential decay with a mean distribution t1/2 of 0.23 hours and terminal t1/2 of 2.53 hours was observed. Total clearance correlated well with and exceeded creatinine clearance by a factor of 2.4. Mean volume of the central compartment was 15.26 L/1.73 m2 and the volume of distribution at steady state was 32.8 L/1.73 m2. Peak (model predicted) and trough plasma concentrations were 4.75 to 6.20 micrograms/ml and less than 0.25 to 0.63 microgram/ml, respectively, in patients receiving 2.5 mg/kg. Peak concentrations are well above those needed to inhibit HCMV at the 50% level (ID50) and troughs are near this ID50. Cerebrospinal fluid concentrations of DHPG indicate a penetration of 24% to 67%. No accumulation of DHPG was apparent in these patients. However, dosage reduction is necessary in renal insufficiency. Neutropenia occurred in one patient. The plasma concentration profile of DHPG suggests potential beneficial activity against HCMV.