Beatriz E Brito | PubMed Health

PubMed2006

Age as a determinant factor for endotoxin induced uveitis.

PURPOSE: To determine if susceptibility to systemic endotoxin-induced uveitis is an age-related phenomenon in the rabbit. METHODS: Young and adult rabbits were injected intravenously with 2.5 microg/kg of E. coli endotoxin or saline. Thereafter, the number of exudating cells at 2, 6, 12, 24 and 48 hours were determined. The levels of lipopolysaccharide-binding protein, total protein, prostaglandin-E2, nitric oxide and interleukin-6 in aqueous humor were also determined 24 hours after the injections. RESULTS: A significant increase in the number of exudating cells and the levels of lipopolysaccharide-binding protein, total protein, prostaglandin-E2 and nitric oxide in aqueous humor was observed only in adult rabbits 24 hours after endotoxin injection. No differences were observed in the increased IL-6 levels. CONCLUSIONS: Life stage seems to be a critical factor in developing an eye-inflammatory response induced by systemic endotoxin. This could be a consequence of a differential specific activation of the ocular immune response.

Age Factors↗

PubMed2004

Toll-like receptor 4 and CD14 expression in human ciliary body and TLR-4 in human iris endothelial cells.

We investigated the expression of the functional endotoxin receptor proteins Toll-like receptor-4 and CD14 in human eyes. Toll-like receptor-4 and CD14 proteins were detected by immunohistochemical analysis of sections of whole human eyes embedded in paraffin with monoclonal antibodies against human toll-like receptor-4 (HTA-125), human CD14 (RPA-M1), or as a control, an irrelevant mouse IgG1k (MOPC-21). Incubation of explants with a neutralizing anti-toll-like receptor-4 monoclonal antibody was used to determine if lipopolysaccharide stimulation of tumor necrosis factor or interleukin-6 secretion was dependent on Toll-like receptor-4 activity. Reverse transcription-polymerase chain reaction was used to detect mRNAs for toll-like receptor-4, tumor necrosis factor-alpha, interleukin-1beta, interleukin-6 and interleukin-8, 3 hr after stimulation of cultured iris microvascular endothelial cells. By immunohistochemistry, human ciliary body non-pigmented epithelial cells showed strong expression of the endotoxin receptor proteins, toll-like receptor-4 and CD14. Toll-like receptor-4 antibodies significantly inhibited lipopolysaccharide-stimulated tumor necrosis factor secretion by the ciliary body. Toll-like receptor-4 mRNA was constitutively expressed in iris endothelial cells and slightly down-regulated by endotoxin. mRNA levels for tumor necrosis factor-alpha, interleukin-1beta, interleukin-6 and interleukin-8 were all increased by endotoxin treatment. This is the first report that shows intraocular (ciliary body and iris) expression of toll-like receptor-4, other than in cornea. Our results show that the ciliary body also expresses CD14, which is anatomically colocalized with toll-like receptor-4. This suggests a potential interaction between both molecules during endotoxin activation of ciliary body cells. The juxtaposition of toll-like receptor-4 and CD14 in the anterior uveal tract helps to explain the sensitivity of the iris/ciliary body to bacterial endotoxin as seen in the standard animal model of endotoxin-induced uveitis.

Adult↗