title: Modulation of neural activation following treatment of hepatic encephalopathy.
abstract: OBJECTIVE
  To measure changes in psychometric state, neural activation, brain volume (BV), and cerebral metabolite concentrations during treatment of minimal hepatic encephalopathy.
  
  
  METHODS
  As proof of principle, 22 patients with well-compensated, biopsy-proven cirrhosis of differing etiology and previous minimal hepatic encephalopathy were treated with oral l-ornithine l-aspartate for 4 weeks. Baseline and 4-week clinical review, blood chemistry, and psychometric evaluation (Psychometric Hepatic Encephalopathy Score and Cognitive Drug Research Score) were performed. Whole-brain volumetric and functional MRI was conducted using a highly simplistic visuomotor task, together with proton magnetic resonance spectroscopy of the basal ganglia. Treatment-related changes in regional BV and neural activation change (blood oxygenation level dependent) were assessed.
  
  
  RESULTS
  Although there was no change in clinical, biochemical state, basal ganglia magnetic resonance spectroscopy, or in regional BV, there were significant improvements in Cognitive Drug Research Score (+1.2, p = 0.003) and Psychometric Hepatic Encephalopathy Score (+1.5, p = 0.003) with treatment. This cognitive amelioration was accompanied by changes in blood oxygenation level-dependent activation in the posterior cingulate and ventral medial prefrontal cortex, 2 regions that form part of the brain's structural and metabolic core. In addition, there was evidence of greater visual cortex activation.
  
  
  CONCLUSIONS
  These structurally interconnected regions all showed increased function after successful encephalopathy treatment. Because no regional change in BV was observed, this implies that mechanisms unrelated to astrocyte volume regulation were involved in the significant improvement in cognitive performance.
authors: Hepatology & Gastroenterology Section, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, St. Mary's Hospital Campus, Imperial College London, UK.
authors: Mark J W
authors: MJ
authors: McPhail
authors: Robert
authors: R
authors: Leech
authors: Vijay P B
authors: VP
authors: Grover
authors: Julie A
authors: JA
authors: Fitzpatrick
authors: Novraj S
authors: NS
authors: Dhanjal
authors: Mary M E
authors: MM
authors: Crossey
authors: Henning
authors: H
authors: Pflugrad
authors: Brian K
authors: BK
authors: Saxby
authors: Keith
authors: K
authors: Wesnes
authors: M Alex
authors: MA
authors: Dresner
authors: Adam D
authors: AD
authors: Waldman
authors: Howard C
authors: HC
authors: Thomas
authors: Simon D
authors: SD
authors: Taylor-Robinson
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001921:Brain / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D004151:Dipeptides / Q000008:administration & dosage / Q000627:therapeutic use; D005260:Female; D006501:Hepatic Encephalopathy / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000187:drug effects / Q000378:metabolism*; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology*; D016896:Treatment Outcome
chemical_list: D004151:Dipeptides; C002939:ornithylaspartate