Effective treatment of experimental uveitis with interleukin-1 blockers, CK 123 and CK 124

Cytokines and chemokines in uveitis: is there a correlation with clinical phenotype?

Uveitis is a general term for intraocular inflammation and includes a large number of clinical phenotypes. As a group of disorders, it is responsible for 10% of all registered blind patients under the age of 65 years. Immune-mediated uveitis may be associated with a systemic disease or may be localized to the eye. The pro-inflammatory cytokines interleukin (IL)-1beta, IL-2, IL-6, interferon-gamma and tumor necrosis factor-alpha have all been detected within the ocular fluids or tissues in the inflamed eye together with others, such as IL-4, IL-5, IL-10 and transforming growth factor-beta. The chemokines IL-8, monocyte chemoattractant protein-1, macrophage inflammatory protein (MIP)-1alpha, MIP-1beta and fractalkine are also thought to be involved in the associated inflammatory response. There have been a number of studies in recent years investigating cytokine profiles in different forms of uveitis with a view to determining what cytokines are important in the inflamed eye. This review attempts to present the current state of knowledge from in vitro and in vivo research on the inflammatory cytokines in intraocular inflammatory diseases.

Effect of interleukin-1 blockers, CK112, and CK116 on rat experimental choroidal neovascularization in vivo and endothelial cell cultures in vitro

PURPOSE

The aim of this study was to investigate the effect of interleukin-1 blockers, CK112 and CK116, on laser-induced experimental choroidal neovascularization (CNV) in rat models in vivo and endothelial cell proliferation in vitro.

METHODS

Male Brown Norway rats were anesthetized to receive Nd:YAG laser to break the Bruch's membrane. CK112, CK116, and prednisolone were given once-daily through intraperitoneal (i.p.) injection after laser treatment for 4 weeks. The development of CNV was determined by fluorescein angiography performed on weeks 2 and 4. Human umbilical vein endothelial cells (HUVEC) were tested with proliferation assay with CK112, CK116, and prednisolone at different concentrations.

RESULTS

The intensity of fluorescein leakage from the photocoagulated lesions decreased significantly, compared to the control group (treated with dimethyl sulfoxide [DMSO] only), following CK112, CK116, and prednisolone treatment. Four (4) weeks after administration, CK112, at 10 mg/kg and 30 mg/kg, inhibited CNV development to 75% and 77% of the control group, respectively (P < 0.01). Both CK116, 10 mg/kg, and prednisolone, 5 mg/kg, inhibited the CNV development to 85% of the control group (P < 0.05). All three compounds interfered with the endothelial cell proliferation significantly. The reduction of the endothelial cells was 50.5% (P < 0.01), 28.5% (P < 0.05), and 23.1% (P < 0.05), respectively, in 500 microg/mL, 300 microg/mL, and 100 microg/mL of the CK112-treated group. CK116 inhibited the cell proliferation significantly to 77.2% of the control group at 500 microg/mL (P < 0.05).

CONCLUSIONS

CK112 and CK116 inhibited the development of CNV in the rat model and interfered with vascular endothelial cell proliferation in vitro. Our results suggest that CK112 and CK116 may be good candidates to inhibit ocular neovascularization related to age-related macular degeneration (ARMD).

Review: effects of nitric oxide on eye diseases and their treatment

Both underproduction and overproduction of nitric oxide (NO) could lead to various eye diseases. It is known that endothelial NO synthase (eNOS) and neuronal NOS (nNOS) are activated in normal tissues to produce NO for physiological functions. Thus, underproduction of NO results in various eye diseases which could be corrected by providing NOS substrates or NO donors to lower the intraocular pressure, increase ocular blood flow, relax ciliary muscle, etc. On the other hand, immunological NOS (iNOS) is inducible only in pathological conditions by endotoxins, inflammation, and certain cytokines, such as interleukin-1 (IL-1), IL-6, TNF (tumor necrosis factor) and the like. Once induced, iNOS will produce large amounts of NO for long periods of time, so that NO is converted into NO2, nitrite, peroxynitrite and free radicals to induce pathophysiological actions, such as optic nerve degeneration and posterior retinal degeneration lesion, which lead to glaucoma, retinopathy, age-related macular degeneration (AMD), myopia, cataracts and uveitis. To treat/prevent these eye diseases, inhibitors of iNOS activity and/or iNOS induction could be tried.

Inhibition of interleukin-1-induced uveitis and corneal fibroblast proliferation by interleukin-1 blockers

Interleukin-1 (IL-1) is known to trigger induction of inducible nitric oxide synthase (iNOS) to persistently mass produce nitric oxide (NO) to induce various diseases such as cancer, inflammation, Alzheimer's disease and eye diseases, including uveitis, retinopathy, age-related macular degeneration, glaucoma and myopia. Therefore, IL-1 blockers could become an important class of drugs to fight numerous diseases. Among the many compounds studied so far, 1-methyl hydrazino analogs are among the most promising agents to be developed. A minor structural change of 1-methyl hydrazino group into 1-methyl thiosemicarbazido group enhanced their anti-inflammatory activity but reduced their antiproliferation activity on corneal fibroblast cell growth.

Suppression of interleukin-1alpha-induced uveitis and inhibition of fibroblast-like cell proliferation by synthetic interleukin-1 blockers

To treat uveitis and prolong the functional life of filtration surgery on glaucomatous eyes, some interleukin-1 (IL-1) blockers were used to inhibit IL-1-induced uveitis in rat eyes and to suppress proliferation of fibroblast-like corneal and conjunctival cells in the cell cultures, respectively. It was found in this research that the blood-aqueous barrier can be broken by IL-1alpha to allow fluorescein to enter the eyeballs and to be detected by fluorotron. The uveitis was effectively blocked by the IL-1 blockers studied in this research. It was also noted that the proliferation of fibroblast-like corneal and conjunctival cells was effectively inhibited by IL-1 blockers. The inhibition of cell growth seems to be caused primarily by the inhibition of RNA synthesis. There was a significant difference in the potency of IL-1 blockers to inhibit corneal vs. conjunctival cells. It was noted that conjunctival cells were more easily inhibited by IL-1 blockers than corneal cells. These results indicate that IL-1 blockers can suppress the proliferation of conjunctival cells at dose levels which do not affect the normal cell growth of corneal cells.

Anti-uveitis and inhibition of fibroblast-like corneal and conjunctival cells by interleukin-1 blockers

Effects of interleukin-1 (IL-1) blockers, CK130 and CK131, on IL-1-induced uveitis and proliferation of fibroblast-like corneal and conjunctival cells were investigated in this study. It was found that CK130 and CK131 inhibited IL-1-induced uveitis in rat eyes effectively at 3 mg/kg and 10 mg/kg, respectively. Further, CK130 and CK131 inhibited fibroblast-like corneal and conjunctival cell growth effectively at 10-300 microg/ml and 30-300 microg/ml, respectively. It was also found that DNA synthesis was markedly reduced by CK130 and CK131 at 30-100 microg/ml. RNA synthesis was also inhibited by these CK compounds but protein synthesis was little affected or enhanced.