ABSTRACT
PURPOSE: In this study, we developed an ex vivo functional assay to assess liver metabolic capacity adapted from the lidocaïne test in rats. METHODS: Animals used were subjected to different models of liver injury: hypothermic ischemia (H/I, n = 8), ischemia-reperfusion (I/R, n = 8) and CCl4 induced liver cirrhosis (n = 11), and compared with sham operated rats (n = 5). Livers were then extracted and a fragment of whole tissue was incubated with lidocaïne for 15, 30, 60, 120, 240, 360, and 720 min at which both lidocaïne and its major metabolite monoethylglycinexylidide (MEGX) were measured by high performance liquid chromatography (HPLC). A histological study and biochemical assays (transaminase levels) were also performed to further evaluate and confirm our data. RESULTS: Pharmacokinetic profile of lidocaïne metabolism in sham-operated animals revealed that the maximum concentration of MEGX is achieved at 120 min. Both lidocaïne metabolism and MEGX formation levels were significantly altered in all three models of hepatic injury. The extent of hepatic damage was confirmed by increased levels of transaminase levels and alteration of hepatocyte's structure with areas of necrosis. CONCLUSION: Our method provides reliable and reproducible results using only a small portion of liver which allows for a fast and easy assessment of liver metabolic capacity. Moreover, our method presents an alternative to the in vivo technique and seems more feasible in a clinical setting.
ABSTRACT
Inflammation participates in the genesis and progression of hypoxic-ischemic brain injury. Interleukin (IL)-1 is a major pro-inflammatory cytokine, which plays a dominant role in hypoxic-ischemic (and postinfectious) brain damage. Abundant evidence reveals the principal involvement of IL-1 over other pro-inflammatory cytokines. IL-1 interacts with the IL-1 receptor I (IL-1RI). The natural IL-1 receptor antagonist (IL-1ra) is a large 17.5-kDa peptide that competes with IL-1 for its binding site on IL-1RI. Recombinant IL-1ra (Kineret) is effective in human inflammatory conditions. However, a number of drawbacks of IL-1ra limit its broader use; these include injection site reactions [70%], broad immunosuppression, and high costs. We hereby report the characterization of a small (peptide) IL-1RI antagonist we developed, namely rytvela (termed 101.10), and its efficacy in models of (gut) inflammation and of newborn hypoxic-ischemic brain injury. Experiments reveal that 101.10 is selective for the IL-1RI and inhibits to a variable extent different effects induced by IL-1. 101.10 is effective in vivo (on systemic as well as oral administration) in established models of inflammation involving IL-1, notably in inflammatory bowel disease, and is superior to dexamethasone. In a rat pup model of hypoxic-ischemic brain injury (Rice-Vannucci model), where IL-1 and IL-1R expression is increased, 101.10 preserved microvascular density, parenchymal integrity, and brain mass. In conclusion, we hereby describe for the first time the discovery of a stable, potent, and effective specific IL-1RI small (peptide) antagonist, namely 101.10 (rytvela), which exhibits allosteric modulatory properties, and is effective in vivo in models of inflammation (known to involve IL-1) and in particular in hypoxic-ischemic newborn brain injury. 101.10 (and small alike compounds) may be suitable alternatives to IL-1ra.
