One of the neurological alterations in patients with minimal or overt hepatic encephalopathy is cognitive impairment. This impairment is reproduced in rats with chronic liver failure due to portacaval shunt (PCS). These rats show decreased ability to learn a conditional discrimination task in a Y‐maze, likely due to reduced function of the glutamate–nitric oxide (NO)–cyclic guanosine monophosphate (cGMP) pathway in brain. It has been proposed that inflammation exacerbates the neuropsychological alterations induced by hyperammonemia, suggesting that inflammation‐associated alterations may contribute to cognitive impairment in hepatic encephalopathy. This study assessed whether treatment with an anti‐inflammatory drug, ibuprofen, is able to restore the function of the glutamate‐NO‐cGMP pathway in cerebral cortex in brain in vivo and/or learning ability in PCS rats. We show that PCS rats have increased levels of interleukin‐6 and increased activities of cyclooxygenase and of inducible NO synthase in cerebral cortex, indicating the presence of inflammation. Chronic treatment with ibuprofen normalizes cyclooxygenase and inducible NO synthase activities but not interleukin‐6 levels. Moreover, ibuprofen normalizes the function of the glutamate‐NO‐cGMP pathway in cerebral cortex in vivo and completely restores the ability of rats with chronic liver failure to learn the Y‐maze task. This supports that inflammation contributes to the cognitive impairment in hepatic encephalopathy. Conclusion: the results reported point to the possible therapeutic utility of decreasing inflammation in the treatment of the cognitive deficits in patients with minimal or overt hepatic encephalopathy. (HEPATOLOGY 2007.)

Background and Aims Patients with liver cirrhosis may present minimal hepatic encephalopathy (MHE) that can be unveiled using specific neuropsychologic examination. Evaluation of MHE in cirrhotic patients might have prognostic value. The psychometric HE score (PHES) has been recommended as the “gold standard” in the diagnosis of MHE. It has been proposed that critical flicker frequency (CFF) analysis would be useful for easier detection of MHE. It would also be useful to have some peripheral parameter that could reflect the presence of MHE. It has been recently proposed that inflammation-associated alterations and hyperammonemia may cooperate in the induction of hepatic encephalopathy. The aim of the present work was to assess whether there is a correlation between the alterations in parameters reflecting inflammation, hyperammonemia, and the presence of MHE. Methods We have studied in 55 patients with liver cirrhosis and 26 controls the performance in the PHES battery and the CFF, ammonia, and some interleukins (ILs) as inflammatory markers. Results IL-6 and IL-18 were significantly higher (2.5-fold and 2.2-fold, respectively) in patients with MHE than in those without MHE. There were significant correlations between IL-6 or IL-18 levels and PHES score and CFF. Moreover, all patients with MHE had IL-6 levels higher than 11 ng/mL, whereas all patients without MHE had IL-6 levels lower than 11 ng/mL. Conclusions Inflammatory alterations related with IL-6 and IL-18 may contribute to MHE. Serum concentration of IL-6 and IL-18 may be useful to discriminate cirrhotic patients with and without MHE.