There is growing evidence that hepatitis C virus (HCV)-infection may affect the brain. About half of the HCV-infected patients complain of chronic fatigue irrespective of their stage of liver disease or virus replication rate.
Even after successful antiviral therapy, fatigue persists in about one-third of the patients. Many patients, in addition, report of deficits in attention, concentration and memory, some also of depression.
Psychometric testing revealed deficits in attention and verbal learning ability as characteristic for HCV-afflicted patients with normal liver function. Magnetic resonance spectroscopic studies showed alterations of the cerebral choline, N-acetyl-aspartate, and creatine content in the basal ganglia, white matter and frontal cortex, respectively.
Recently, pathologic cerebral serotonin and dopamine transporter binding and regional alterations of the cerebral glucose utilization compatible with alterations of the dopaminergic attentional system were observed.
Several studies detected HCV in brain samples or cerebro-spinal fluid.
Interestingly, viral sequences in the brain often differed from those in the liver, but were closely related to those found in lymphoid tissue. Therefore, the Trojan horse hypothesis emerged: HCV-infected mononuclear blood cells enter the brain, enabling the virus to reside within the brain (probably in microglia) and to infect brain cells, especially astrocytes. [Microglia are tiny cells found in the spinal cord and brain. Their activation is a common sign of a neuro-inflammatory disorder such as encephalitis or stroke, and though they’re not well understood, it is known they can perform either protective or harmful functions. Astrocytes are neuron-generating cells.]
Source: Metabolic Brain Disorders, Jan 7, 2009. PMID: 19130196, by Weissenborn K, Tryc AB, Heeren M, Worthmann H, Pflugrad H, Berding G, Bokemeyer M, Tillmann HL, Goldbecker A. Department of Neurology, Hannover Medical School, 30623, Hannover, Germany. [E-mail: Weissenborn.Karin@mh-hannover.de]