Longitudinal neurometabolic changes in the hippocampus of a rat model of chronic hepatic encephalopathy

JOURNAL OF HEPATOLOGY

卷:71

Article

Braissant, Olivier^1,2  Rackayova, Veronika^3,4  Pierzchala, Katarzyna⁴  Grosse, Jocelyn⁵  McLin, Valerie A.^6,7  Cudalbu, Cristina⁴ 

[1] Univ Lausanne, Serv Clin Chem, Lausanne, Switzerland

[2] Univ Hosp Lausanne, Lausanne, Switzerland

[3] Ecole Polytech Fed Lausanne, Ctr Biomed Imaging, Lab Funct & Metab Imaging, Lausanne, Switzerland

[4] Ecole Polytech Fed Lausanne, Ctr Imagerie Biomed CIBM, Lausanne, Switzerland

[5] Ecole Polytech Fed Lausanne, Sch Life Sci, Brain Mind Inst, Lab Behav Genet, Lausanne, Switzerland

[6] Univ Hosp Geneva, Dept Pediat Gynecol & Obstet, Swiss Pediat Liver Ctr, Geneva, Switzerland

[7] Univ Geneva, Med Sch, Geneva, Switzerland

关键词: In vivo proton magnetic resonance spectroscopy;    Hepatic encephalopathy;    Brain metabolism;    Bile duct ligated;    Rats;    Chronic liver disease;    Cholestasis;   

DOI  :  10.1016/j.jhep.2019.05.022

来源: Elsevier

【 摘 要 】

Background & Aims: The sequence of events in hepatic encephalopathy (HE) remains unclear. Using the advantages of in vivo 1H-MRS (9.4T) we aimed to analyse the time-course of disease in an established model of type C HE by analysing the longitudinal changes in a large number of brain metabolites together with biochemical, histological and behavioural assessment. We hypothesized that neurometabolic changes are detectable very early, and that these early changes will offer insight into the primary events underpinning HE. Methods: Wistar rats underwent bile-duct ligation (BDL) and were studied before BDL and at post-operative weeks 2, 4, 6 and 8 (n = 26). In vivo short echo-time H-1-MRS (9.4T) of the hippocampus was performed in a longitudinal manner, as were biochemical (plasma), histological and behavioural tests. Results: Plasma ammonium increased early after BDL and remained high during the study. Brain glutamine increased (+47%) as early as 2-4 weeks post-BDL while creatine (-8%) and ascorbate (-12%) decreased. Brain glutamine and ascorbate correlated closely with rising plasma ammonium, while brain creatine correlated with brain glutamine. The increases in brain glutamine and plasma ammonium were correlated, while plasma ammonium correlated negatively with distance moved. Changes in astrocyte morphology were observed at 4 weeks. These early changes were further accentuated at 6-8 weeks post-BDL, concurrently with the known decreases in brain organic osmolytes. Conclusion: Using a multimodal, in vivo and longitudinal approach we have shown that neurometabolic changes are already noticeable 2 weeks after BDL. These early changes are suggestive of osmotic/oxidative stress and are likely the premise of some later changes. Early decreases in cerebral creatine and ascorbate are novel findings offering new avenues to explore neuroprotective strategies for HE treatment. Lay summary: The sequence of events in chronic hepatic encephalopathy (HE) remains unclear, therefore using the advantages of in vivo proton magnetic resonance spectroscopy at 9.4T we aimed to test the hypothesis that neurometabolic changes are detectable very early in an established model of type C HE, offering insight into the primary events underpinning HE, before advanced liver disease confounds the findings. These early, previously unreported neurometabolic changes occurred as early as 2 to 4 weeks after bile-duct ligation, namely an increase in plasma ammonium and brain glutamine, a decrease in brain creatine and ascorbate together with behavioural and astrocyte morphology changes, and continued to progress throughout the 8-week course of the disease. (C) 2019 European Association for the Study of the Liver. Published by Elsevier B.V.

【 授权许可】

Free