Levels of chemokines and other inflammatory mediators in patients with mild cognitive impairment undergoing rehabilitation

Abstract

Alzheimer's disease is the most common neurodegenerative disease in old age. In some cases, it is preceded by mild cognitive impairment (MCI). One of the important components in the pathogenesis of neurodegeneration is chronic neuroinflammation (inflammatory activation of microglia and astrocytes in the brain). Systemic inflammatory response and immune dysregulation may contribute to neuroinflammation. The purpose of this study was to investigate the level of chemokines and other inflammatory mediators in patients with MCI who underwent medical rehabilitation, and to study its associations with the severity of cognitive impairment. The study group included 48 patients with MCI undergoing rehabilitation. Rehabilitation included cognitive therapy, psychotherapy and tasks for unaided performance. Repeated examination was conducted 6 months after the completion of rehabilitation. The control group included 46 healthy volunteers. Multiplex assay was used to determine serum cytokine and chemokine concentrations. Student's t-test was used to assess the significance of differences. Assessment of cognitive functions was performed using international neuropsychological scales. In patients with MCI, we have found an increase in the levels of several cytokines and chemokines (TNFα, CXCL10/IP10, MDC) that regulate systemic inflammation, cellular and humoral mechanisms of adaptive immunity. After the rehabilitation course their levels returned to normal. It was also found that decrease in CCL7 level in the patients before the rehabilitation course is associated with the severity of cognitive impairment. The findings contribute to understanding the role of chemokines in the pathogenesis of MCI, and indicate that their levels can be potential biomarkers of the severity of cognitive impairment. For translation of the findings into clinical practice, their validation in larger studies is needed, as well as assessing the associations between chemokine levels and the severity of cognitive impairment in MCI over long-term follow-up.