Although the body needs inflammation to fight off infections, this product of the innate immune system has been linked to many health problems when inflammatory molecules are released in excess. The newest study has connected inflammation as a side effect from a hepatitis C treatment to structural changes in the striatum, the reward center of the brain.
Inflammation is known to increase the risk of depression, a relationship developed and exacerbated by certain behavior changes:
- Difficulty focusing
- Lack of motivation
- Reduced experience of pleasure
In a study of 23 patients with hepatitis C, researchers observed how each participant reacted to a treatment of interferon-alpha over several weeks. Interferon-alpha has been used in a clinical setting for over 16 years, successfully fighting infections by priming the immune response with cytokine regulation (Journal of Leukocyte Biology
). The study was published in Biological Psychiatry.
Four hours after receiving the interferon-alpha treatment, the researchers could already see “microstructural changes” in the striatum, as compared to the striatum before treatment, using magnetization transfer imaging.
In the weeks following treatment, participants also reported fatigue and depression, especially between weeks 4 and 12. However, the impact of interferon-alpha appeared to be twofold, with both protective changes in structure and changes that increased the risk of fatigue visible in the striatum. No visible changes were directly linked to depression, though.
“The heterogeneous striatal response may suggest that fatigue and mood are supported by different microcircuits within the striatum,” explained Dr. John Krystal, Editor of Biological Psychiatry
, in response to the dual change. Scientists might soon be looking for structural changes in places in the brain other than the striatum to link back to the reports of depression.