crx-526 and Disease-Models--Animal

Toll like receptor 4 (TLR4) represents a critical cellular link for endotoxin-induced pathology. The aim of this study was to evaluate the potential role of TLR4 inhibition on the intestinal microcirculation during experimental endotoxemia.. The intestinal microcirculation was studied by intravital microscopy in four groups of Lewis rats (n=10 per group): healthy controls (CON group), endotoxemic animals (15mg/kg lipopolysaccharide, LPS group), endotoxemic animals treated with a TLR4 antagonist (1mg/kg CRX-526, LPS+CRX526 group), and controls treated with CRX-526 (C-CRX526 group). Plasma samples were obtained for cytokine measurements at the end of the experiments.. Endotoxemia significantly increased leukocyte adhesion in intestinal submucosal venules (e.g., V1 venules: CON 20.4±6.5n/mm(2), LPS 237.5±36.2n/mm(2), p<0.05) and reduced capillary perfusion of the intestinal wall (e.g., longitudinal muscular layer: CON 112.5±5.9cm/cm(2), LPS 71.3±11.0cm/cm(2), p<0.05) at 2h. TLR4 inhibition significantly reduced endotoxemia-associated leukocyte adhesion (V1 venules: 104.3±7.8n/mm(2)) and improved capillary perfusion (longitudinal muscular layer: 111.0±12.3cm/cm(2)). Cytokine release was not significantly affected.. The TLR4 pathway may be a target in clinical Gram-negative sepsis since administration of the TLR4 antagonist CRX-526 improved intestinal microcirculation parameters in experimental endotoxemia.

Topics: Animals; Capillaries; Cell Adhesion; Cytokines; Disease Models, Animal; Endotoxemia; Glucosamine; Gram-Negative Bacteria; Inflammation; Intestines; Intravital Microscopy; Leukocytes; Lipopolysaccharides; Male; Microcirculation; Perfusion; Rats; Rats, Inbred Lew; Sepsis; Toll-Like Receptor 4

Current evidence indicates that the chronic inflammation observed in the intestines of patients with inflammatory bowel disease is due to an aberrant immune response to enteric flora. We have developed a lipid A-mimetic, CRX-526, which has antagonistic activity for TLR4 and can block the interaction of LPS with the immune system. CRX-526 can prevent the expression of proinflammatory genes stimulated by LPS in vitro. This antagonist activity of CRX-526 is directly related to its structure, particularly secondary fatty acyl chain length. In vivo, CRX-526 treatment blocks the ability of LPS to induce TNF-alpha release. Importantly, treatment with CRX-526 inhibits the development of moderate-to-severe disease in two mouse models of colonic inflammation: the dextran sodium sulfate model and multidrug resistance gene 1a-deficient mice. By blocking the interaction between enteric bacteria and the innate immune system, CRX-526 may be an effective therapeutic molecule for inflammatory bowel disease.

Topics: Adjuvants, Immunologic; Animals; Anti-Inflammatory Agents, Non-Steroidal; ATP Binding Cassette Transporter, Subfamily B, Member 1; Caproates; Cells, Cultured; Colitis; Dextran Sulfate; Disease Models, Animal; Female; Glucosamine; HeLa Cells; Humans; Inflammatory Bowel Diseases; Lipid A; Lipopolysaccharides; Mice; Mice, Inbred BALB C; Mice, Inbred C3H; Mice, Knockout; Monocytes; Receptors, Immunologic; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha