Early primary biliary cholangitis is characterised by brain abnormalities on cerebral magnetic resonance imaging

BACKGROUND

Brain change can occur in primary biliary cholangitis (PBC), potentially as a result of cholestatic and/or inflammatory processes. This change is linked to systemic symptoms of fatigue and cognitive impairment.

AIM

To identify whether brain change occurs early in PBC. If the change develops early and is progressive, it may explain the difficulty in treating these symptoms.

METHODS

Early disease brain change was explored in 13 patients with newly diagnosed biopsy-proven precirrhotic PBC using magnetisation transfer, diffusion-weighted imaging and ¹ H magnetic resonance spectroscopy. Results were compared to 17 healthy volunteers.

RESULTS

Cerebral magnetisation transfer ratios were reduced in early PBC, compared to healthy volunteers, in the thalamus, putamen and head of caudate with no greater reduction in patients with greater symptom severity. Mean apparent diffusion coefficients were increased in the thalamus only. No ¹ H magnetic resonance spectroscopy abnormalities were seen. Serum manganese levels were elevated in all PBC patients, but no relationship was seen with imaging or symptom parameters. There were no correlations between neuroimaging data, laboratory data, symptom severity scores or age.

CONCLUSIONS

This is the first study to be performed in this precirrhotic patient population, and we have highlighted that neuroimaging changes are present at a much earlier stage than previously demonstrated. The neuroimaging abnormalities suggest that the brain changes seen in PBC occur early in the pathological process, even before significant liver damage has occurred. If such changes are linked to symptom pathogenesis, this could have important implications for the timing of second-line-therapy use.

Cerebral microglial activation in patients with hepatitis C: in vivo evidence of neuroinflammation

Patients with chronic hepatitis C infection may exhibit neuropsychological symptoms and cognitive impairment. Post-mortem studies of hepatitis C virus HCV quasispecies and replicative intermediates indicate that the brain might act as a separate compartment for viral replication and microglia may be the locus for infection and subsequent neuroinflammatory activity. We sought to use two independent in vivo imaging techniques to determine evidence of neuroinflammation in patients with histologically mild chronic hepatitis C. Using positron emission tomography (PET) with a ligand for microglial/brain macrophage activation, (11)C-(R)-PK11195 (PK11195) and cerebral proton magnetic resonance spectroscopy, we determined whether there was evidence of neuroinflammation in a pilot study of 11 patients with biopsy-proven mild chronic hepatitis C, compared to healthy volunteers. Patients were characterized by cognitive testing and the fatigue impact scale to assess for CNS impairment. PK11195 binding potential was significantly increased in the caudate nucleus of patients, compared to normal controls (P = 0.03). The caudate and thalamic binding potential were more significantly increased in six patients with genotype 1 infection (P = 0.007) and positively correlated with viraemia (r = 0.77, P = 0.005). Basal ganglia myo-inositol/creatine and choline/creatine ratios were also significantly elevated in patients with chronic hepatitis C compared to normal controls (P = 0.0004 and P = 0.01, respectively). Using PET, we demonstrated evidence of microglial activation, which positively correlated with HCV viraemia and altered cerebral metabolism in the brains of patients with mild hepatitis C. This provides further in vivo evidence for a neurotropic role for HCV.

Does acute hepatitis C infection affect the central nervous system in HIV-1 infected individuals?

Central nervous system (CNS) manifestations of chronic hepatitis C virus (HCV) and chronic human immune deficiency virus-1 (HIV-1) infections have been reported, but the impact of acute HCV infection on the CNS is unknown. A total of 10 individuals with chronic stable HIV-1 with documented acute HCV (HCV-RNA polymerase chain reaction positive and HCV antibody negative, group 1) underwent cerebral proton magnetic resonance spectroscopy (MRS) using acquisition parameters to quantify myo-inositol/creatine (mI/Cr) ratio in the right basal ganglia (RBG). Two matched control groups also underwent MRS; group 2: ten with chronic HIV-1 and no evidence of HCV, and group 3: ten with no evidence of HIV or HCV. Subjects also underwent computerized neurocognitive assessments (CogState). RBG mI/Cr ratio in group 1 (acute HCV in a background of HIV) was significantly lower than that in groups 2 and 3 [2.90 (+/-0.7) vs 3.34 (+/-0.4) and 3.43 (+/-0.4), mean (SD) for group 1 vs 2 and 3 respectively, P = 0.049], with 50% of subjects in group 1 having a mI/Cr ratio below the lowest observed ratio in either of the other groups. On neurocognitive testing, significant defects in the monitoring domain were observed in group-1, compared with matched controls (P = 0.021). Acute HCV in HIV-1 infected subjects is associated with CNS involvement. Clinicians should be vigilant of early CNS involvement when assessing subjects with acute HCV.