The sialyl Lewis X analogue, CY-1503, down-regulates leucocyte-endothelium interactions and the inflammatory response.

OBJECTIVE: To elucidate mechanisms of protection of ischaemic liver with the sialyl Lewis X analogue CY-1503 by regulation of inflammatory mediators such as oxygen free radicals and cytokines as well as blocking the migration of leucocytes. DESIGN: Laboratory study. SETTING: Teaching hospital, Spain. ANIMALS: 122 male Sprague-Dawley rats divided into four groups: normal (n = 18), sham-operated (n = 28), ischaemic controls (n = 38), and CY-1503 (n = 38). INTERVENTIONS: Warm total hepatic ischaemia for 90 minutes followed by various periods of reperfusion. MAIN OUTCOME MEASURES: Survival, liver histology, liver function, neutrophil infiltration, and free radical and cytokine concentrations. RESULTS: 2/20 ischaemic controls survived, compared with 14/20 given CY-1503. Liver function was better, as was histological appearance judged by the Suzuki score); myeloperoxidase activity was significantly decreased (n = 6 in each group, p<0.01) as were concentrations of free radicals (n = 12 in each group, p<0.05) in the group given CY-1503. CY-1503 had no effect on concentrations of the cytokines tumour necrosis factor-alpha or interleukin 1-alpha. CONCLUSIONS: CY-1503 exerts a protective effect in that it able to down-regulate concentrations of free radicals in our rat model. It is a potent inhibitor of neutrophil migration, but has no effect on cytokine concentrations.

Tacrolimus (FK506) down-regulates free radical tissue levels, serum cytokines, and neutrophil infiltration after severe liver ischemia.

BACKGROUND: Liver ischemia and reperfusion injury is associated with activation of multiple inflammatory pathways, including free radicals, cytokines, and neutrophil-mediated tissue damage among others. Tacrolimus (FK506) has shown important regulatory effects on some inflammatory pathways, such as cytokines, neutrophils, and adhesion molecules. In this study, we explored a new potential protective mechanism for tacrolimus in the liver inflammatory response after ischemia and reperfusion, specifically its effect on liver tissue free radicals. METHODS: Total hepatic ischemia was produced in the rat for 90 min with an extracorporeal portosystemic shunt. Animals (n=96) were divided into four groups: group 1 comprised normal rats for reference values; group 2 comprised sham operated rats; in group 3, ischemic control rats received only the vehicle; and the experimental treatment group, group 4, received tacrolimus at a dose of 0.3 mg/kg, 4 hr before ischemia. Animal survival was followed up to 7 days. Liver function tests were performed and liver tissue free radicals and myeloperoxidase, serum cytokines (interleukin 1, tumor necrosis factor-alpha), and liver histology were measured 4 hr after reperfusion. RESULTS: Seven-day survival was significantly improved from only 20% in the control group to 55% in the tacrolimus group (P<0.01). Liver function tests, histology, and myeloperoxidase tissue values were significantly improved (P<0.05) with tacrolimus pretreatment. Furthermore, a significant (P<0.05) down-regulation of serum cytokines and liver tissue free radicals was observed. CONCLUSIONS: These data indicate a new and different protective mechanism for FK506 in regard to its ability to down-regulate free radical levels in livers subjected to severe ischemia and reperfusion. Tacrolimus, also confirmed to be a potent suppressor of the cytokine response, specifically interleukin 1 and tumor necrosis, decreased neutrophil tissue migration as well.

Sulfo-Lewis(x) diminishes neutrophil infiltration and free radicals with minimal effect on serum cytokines after liver ischemia and reperfusion.

BACKGROUND: Cell adhesion plays a central role in the pathogenesis of neutrophil-induced hepatic injury after ischemia and reperfusion. Sialyl Lewis(x) binds to selectins mediating neutrophil adherence to endothelium, thereby facilitating subsequent migration and tissue damage. AIM: We studied the effect of a novel sulfo-derivative of sialyl Lewis(x), GM-1998, on the liver inflammatory response after ischemia and reperfusion. Specifically, we evaluated its impact on three key inflammatory mediators: neutrophil migration, free radicals, and serum cytokines. MATERIAL AND METHODS: Rats were subjected to total hepatic ischemia for 90 min using an extracorporeal portosystemic shunt to avoid splanchnic congestion. GM-1998 was given at a total dose of 20 mg/kg both prior to and after reperfusion. Liver function tests, liver tissue free radicals, and myeloperoxidase (MPO), serum cytokines (IL-1, TNF-alpha), and liver histology were analyzed 4 hr after reperfusion. Additionally, survival was followed for up to 7 days. RESULTS: Seven-day survival significantly increased from 20% in the control group to 65% in the sulfo-Lewis(x) treated group. Liver function tests and histological damage scores were improved in comparison to controls. We observed significant downregulation of free radicals and neutrophil migration. This compound did not significantly affect serum cytokine levels. CONCLUSIONS: GM-1998 showed a protective effect in an in vivo model of severe liver ischemia and reperfusion by decreasing tissue free radical levels and selectin-mediated neutrophil migration. This protective effect was also reflected in improved liver function tests and histological response leading to better survival. We confirmed the beneficial effect of neutrophil blockade as a key target to prevent damage after the reperfusion phenomenon by using a glycomimetic sulfo-Lewis(x).