Evidence for neuroinflammation and neuroprotection in HCV infection-associated encephalopathy

Objective Fatigue, mood disturbances and cognitive dysfunction are frequent in patients infected with hepatitis C virus (HCV) who have mild liver disease. The reason is still unclear. The present study aims to gain more insight into the pathomechanism by combining an extensive neuropsychological examination with magnetic resonance spectroscopy in four different brain regions in a patient group covering the whole spectrum of neuropsychiatric findings in patients afflicted with HCV who have only mild liver disease. Methods 53 HCV-positive patients with only mild liver disease and differing degrees of neuropsychiatric symptoms were studied with single-voxel MRS of the parietal white matter, occipital grey matter, basal ganglia and pons. Brain metabolite concentrations were quantitatively analysed by using LCmodel. MRS data were compared to those of 23 healthy controls adjusted for age, and analysed for relationships with the extent of neuropsychiatric symptoms. Results Choline (p=0.02), creatine (p=0.047) and N-acetyl-aspartate plus N-acetyl-aspartyl-glutamate (NN, p - 0.02) concentrations in the basal ganglia and choline concentrations in the white matter (p=0.045) were significantly higher in the patients than in controls. Interestingly, the difference was most evident for the patients with low fatigue scores (eg, white matter: choline: p=0.001, creatine: p=0.003, NN: p=0.031). Myo-inositol differed significantly between groups in the white (p=0.001) and grey matter (p=0.003). Fatigue correlated negatively with white matter NN, choline and creatine and myo-inositol levels in white and grey matter and basal ganglia (p<0.01). Conclusion As the increase of choline, creatine and myo-inositol are usually interpreted to indicate glial activation and macrophage infiltration in chronic inflammation and slow virus infections of the brain the present data endorse the hypothesis, that HCV infection may induce neuroinflammation and brain dysfunction. The concomitant increase of NN and the negative correlation to the extent of fatigue suggest a cerebral compensatory process after HCV infection.