Overview Pulmonary-Allergy, Dermatological, Gastrointestinal & Arthritis: Novel, non-traditional, non-steroidal, anti-inflammatory agents

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 endotoxin-induced TNF-alpha production in macrophages by 5Z-7-oxo-zeaenol and other fungal resorcylic acid lactones

Resorcylic acid lactones are fungal metabolites that exhibit a wide range of biological properties which includes oestrogenic, antifungal, phytotoxic and anti-inflammatory activity. The capacity of 5Z-7-oxo-zeaenol, a resorcylic lactone of fungal origin and six naturally occurring analogues to inhibit lipopolysaccharide (LPS)-induced cytokine production in phorbol 12-myristate-13-acetate (PMA)-treated cultured myelomonocytic cells (U937) was compared. The activity of the natural analogues in the U937 assay varied over 10(4)-fold, with 5Z-7-oxo-zeaenol the most potent of those tested inhibiting tumour necrosis factor-alpha (TNF alpha) production in these cells with IC50 of 6 nM. The isomeric 7-oxo-zeaenol and structurally more distant monorden (radicicol) were the next most active compounds with IC50 approximately 500 nM, and zearalenone, the least active with IC50 > 400 microM. 5Z-7-oxo-zeaenol retained activity in LPS-stimulated peripheral blood mononuclear cells with an IC50 of 10-25 nM. This compound also inhibited LPS-induced TNF alpha production in whole blood experiments (IC50 100-1000 nM) and lowered serum levels of TNF alpha in mice when administered prior to LPS. 5Z-7-oxo-zeaenol was shown to inhibit the phosphorylation and activation of mitogen-activated protein kinase (MAPK) induced by LPS. These data are consistent with a mechanism of action at or upstream of MAPK with resultant downstream effects. This series of naturally occurring analogues represents an interesting group of compounds with diverse biological properties. Of this series, 5Z-7-oxo-zeanenol has exceptionally potent anti-inflammatory properties exhibited by its strong inhibition of cytokine production.

Anti-inflammation and antifibroblastic actions of interleukin-1 blockers

Interleukin-1 (IL-1) blockers, CK 127 and CK 129, were found to inhibit IL-1-induced posterior uveitis very effectively at 3-10 mg/kg i.p. and were more potent than prednisolone which required at least 20 mg/kg i.p. to achieve the same level of anti-uveitis action. CK 127 and CK 129 were also found to be effective in inhibiting fibroblast-like corneal cells at 30-300 micrograms/ml and conjunctival cells at 0.3-10 micrograms/ml. These results indicate that IL-1 blockers are more potent in inhibiting the cell growth of conjunctival cells than that of corneal cells. From in vitro cell culture experiments, it was found that inhibition of cell growth could be due primarily to the inhibition of DNA. Although the inhibition of cell growth was due mainly to the inhibition of DNA synthesis, mRNA synthesis was also markedly inhibited. In both cells, the protein synthesis was unaffected in a few cases and markedly stimulated in most cases.

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.

A hydrogel based on a polyaspartamide: characterization and evaluation of in-vivo biocompatibility and drug release in the rat

This paper deals with the characterization of a new microparticulate hydrogel obtained by gamma irradiation of alpha, beta-poly[N-(2-hydroxyethyl)-DL-aspartamide] (PHEA). When enzymatic digestion of PHEA hydrogel was evaluated using various concentrations of pepsin and alpha-chymotrypsin no degradation occurred within 24 h. In-vivo studies showed that this new material is biocompatible after oral administration to rats. PHEA hydrogel was also studied as a system for delivery of diflunisal, an anti-inflammatory drug. In-vitro release studies in simulated gastrointestinal juice (pH 1 or 6.8) showed that most of the drug was released at pH 6.8. In-vivo studies indicated that diflunisal-loaded PHEA microparticles significantly improved the gastric tolerance and oral bioavailability of the drug in comparison with free diflunisal. These results suggest the potential application of PHEA hydrogel as a new delivery system for the oral administration of anti-inflammatory drugs.