Cerebral microglia activation in hepatitis C virus infection correlates to cognitive dysfunction

Hepatitis C virus (HCV) infection may induce chronic fatigue and cognitive dysfunction. Virus replication was proven within the brain and HCV-positive cells were identified as microglia and astrocytes. We hypothesized that cerebral dysfunction in HCV-afflicted patients is associated with microglia activation. Microglia activation was assessed in vivo in 22 patients with chronic HCV infection compared to six healthy controls using [(11) C]-PK11195 Positron Emission Tomography (PET) combined with magnetic resonance tomography for anatomical localization. Patients were subdivided with regard to their PCR status, Fatigue Impact Scale score (FIS) and attention test sum score (ATS). A total of 12 patients (54.5%) were HCV PCR positive [of which 7 (58.3%) had an abnormal FIS and 7 (58.3%) an abnormal ATS], 10 patients (45.5%) were HCV PCR negative (5 (50%) each with an abnormal FIS or ATS). Patients without attention deficits showed a significantly higher accumulation of [(11) C]-PK11195 in the putamen (P = 0.05), caudate nucleus (P = 0.03) and thalamus (P = 0.04) compared to controls. Patients with and without fatigue did not differ significantly with regard to their specific tracer binding in positron emission tomography. Preserved cognitive function was associated with significantly increased microglia activation with predominance in the basal ganglia. This indicates a probably neuroprotective effect of microglia activation in HCV-infected patients.

Apolipoprotein E-ε4 deficiency and cognitive function in hepatitis C virus-infected patients

Hepatitis C virus (HCV) causes not only liver damage in certain patients but can also lead to neuropsychiatric symptoms. Previous studies have shown that the type 4 allele of the gene for apolipoprotein E (APOE) is strongly protective against HCV-induced damage in liver. In this study, we have investigated the possibility that APOE genotype is involved in the action of HCV in brain. One hundred HCV-infected patients with mild liver disease underwent a neurological examination and a comprehensive psychometric testing of attention and memory function. In addition, patients completed questionnaires for the assessment of fatigue, health-related quality of life and mood disturbances. Apolipoprotein E gene genotyping was carried out on saliva using buccal swabs. The APOE-ε4 allele frequency was significantly lower in patients with an impairment of working memory, compared to those with a normal working memory test result (P = 0.003). A lower APOE-ε4 allele frequency was also observed in patients with definitely altered attention ability (P = 0.008), but here, the P-value missed the level of significance after application of the Bonferroni correction. Our data suggest that the APOE-ε4 allele is protective against attention deficit and especially against poor working memory in HCV-infected subjects with mild liver disease. Considering the role of apolipoprotein E in the life cycle of the virus, the findings shed interesting new light upon possible pathomechanisms behind the development of neuropsychiatric symptoms in hepatitis C infection.

The temporal profile of inflammatory markers and mediators in blood after acute ischemic stroke differs depending on stroke outcome

BACKGROUND

Early inflammation has been suggested as an important factor contributing to unfavorable prognosis after acute ischemic stroke. The present study aimed to clarify the temporal dynamics of discrete inflammatory markers/mediators for future mechanism-targeting anti-inflammatory strategies in ischemic brain damage.

METHODS

Blood samples of 69 patients with transient ischemic attack or ischemic stroke were taken upon admission and at time points 6, 12 and 24 h, as well as 3 and 7 days after symptom onset for analysis of monocyte chemotactic protein-1 (MCP-1), matrix metalloproteinase-9 (MMP-9), tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), interleukin-6 (IL-6), C-reactive protein (CRP) and the brain damage marker S100B. Clinical scores (modified Rankin Scale, National Institute of Health Stroke Scale) were assessed on day 90.

RESULTS

MCP-1, MMP-9, TIMP-1, IL-6, CRP and S100B showed significantly different time courses depending on stroke outcome. While the levels of IL-6, MCP-1 and MMP-9 increased already a few hours after symptom onset, CRP and S100B gradually rose commencing at 12-24 h. TIMP-1 demonstrated an extended plateau. By multiple linear regression analysis IL-6, MCP-1, TIMP-1 and S100B were determined to be independently related to clinical outcome scores at specific time points.

CONCLUSIONS

Our data show important differences in the early time course of several potential markers for the complex network of inflammation and brain damage after ischemic stroke depending on stroke outcome. This must be considered for any therapeutical approach using anti-inflammatory treatment.