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Hepatic encephalopathy (HE) is a complex neuropsychiatric syndrome resulting from acute or chronic hepatic impairments. The clinical features of HE include attention as well as a mild cognitive deficits associated with impaired attentional and executive networks in patients as well as in animal models of HE. The underlining pathomechanism of memory impairment in HE patients is still not fully understood; however, it may involve a possible gliopathy as well as neuropathy. The aim of the present investigation is to assess progression of short working memory deterioration in acute HE and to delineate the glial and the neuronal alteration which may underlie such cognitive impairment. The study was carried out in male Sprague-Dawley rats with acute liver failure induced by thioacetamide (TAA). The study was performed on different stages of acute HE; 12 h, 24 h and 36 h following administration of TAA. The liver functions were assessed via different biochemical markers (ALT, AST, bilirubin, urea and creatinine) and an histopathological examination of the liver tissue. While for the behavioral study, we used T-Maze test to assess short working memory using the percentage of alternation behavior, together with an immunohistochemical analysis of the Glial Fibrillary Acidic Protein (GFAP) as the key marker of astrocytes in the hippocampus, as well as serotonin (5-HT) for 5-HTergic neurons within the dorsal Raphe nucleus (DRN). Our data revealed a progressive loss of liver tissue integrity with inflammation and hepatocytes degeneration which was associated to obvious loss of the liver function. In parallel, we observed a gradual alteration of the alternation behavior, as a sign of altered short working memory in the acute HE rats. At the central level, the immunohistochemical study showed a time dependent region-specific changes of GFAP-immunoreactive astrocytes within the hippocampus. While within the DRN, serotonin levels declined progressively in a time-dependant manner. Our data revealed for the first time, a gradual loss of short memory function in acute HE, resulting from liver dysfunction. Such cognitive deterioration may involve a possible gliopathy as well as a 5-HTergic dysfunction which could be considered as a new key element for understanding the basis of memory and attention loss in HE patients., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Hepatic encephalopathy (HE) is a major neuropsychological condition that occursas a result of impaired liver function. It is frequently observed in patients with advanced liver disease or cirrhosis. Memory impairment is among the symptoms of HE; the pathophysiologic mechanism for this enervating condition remains unclear. However, it is possible that neuroinflammation may be involved, as recent studies have emphasized such phenomena. Therefore, the aim of the present study is to assess short working memory (SWM) and examine the involvement of microglia in a chronic model of HE. The study was carried out with male Wistar rats that were induced by repeated thioacetamide (TAA) administration (100 mg/kg i.p injection for 10 days). SWM function was assessed through Y-maze, T-Maze, and novel object recognition (NOR) tests, together with an immunofluorescence study of microglia activation within the hippocampal areas. Our data showed impaired SWM in TAA-treated rats that was associated with microglial activation in the three hippocampal regions, and which contributed to cognitive impairment. [ABSTRACT FROM AUTHOR]

Hepatic encephalopathy (HE) is a neurophysiological syndrome secondary to acute or chronic liver failure. Studies showed that HE patients exhibit a deficit in motor coordination, which may result from cerebellar functional impairment. The aim of this study is to assess the time-dependent alteration of locomotor behavior and the glial and neuronal alteration in rat with acute HE induced chemically. The study was carried out in male Sprague-Dawley rats with thioacetamide (TAA) induced acute liver failure at different stages 12 h, 24 h and 36 h. Hepatic and renal functions were assessed via various biochemical and histopathological examinations, while the cerebellum and the midbrain were examined using histology and immunohistochemistry for tyrosine hydroxylase (TH), cyclooxygenase-2 (COX-2) and glial fibrillary acidic protein (GFAP). We used as well, the open field test and the Rotarod test for assessing the locomotor activity and coordination. Our data showed a progressive loss of liver function and a progressive alteration in locomotor behavior and motor coordination in acute HE rats. In the cerebellum, we noted an increase in the degeneration of cerebellar Purkinje neurons parallel to increased COX-2 immunoreactivity together with astrocytic morphology and density changes. Likewise, in substantia nigra pars compacta, TH levels were reduced. We showed through the current study, a progressive deterioration in locomotor behavior in acute HE rats, as a result of Purkinje neurons death and a deficient dopaminergic neurotransmission, together with the morpho-functional astroglial modifications involving the oxidative stress and neuroinflammation. • Acute liver failure in rat elicits progressive time-dependant loss of motor coordination. • Acute hepatic encephalopathy in rat is associated to deficient dopaminergic innervations. • Impaired motor coordination may result from morphological astroglial modifications leading to deep functional disruptions. • Presence of cerebellar neuroinflammation correlated to neuronal death of Purkinje cells. [ABSTRACT FROM AUTHOR]