Cytokine profiles and the role of cellular prion protein in patients with vascular dementia and vascular encephalopathy

Abstract

Understanding inflammatory mechanisms in vascular dementia (VD) is pivotal for achieving better insights into changes in brain metabolism. We performed cytokine profiling and measured levels of the cellular prion protein (PrPC) in serum and cerebrospinal fluid (CSF) samples from patients with VD and with vascular encephalopathy (VE). Significant changes were observed for interleukin (IL)-1β, IL-4, IL-5, tumor necrosis factor alpha, interferon gamma, granulocyte-colony stimulating factor, monocyte chemotactic protein 1, and macrophage inflammatory protein 1 beta in serum and for IL-6 and granulocyte macrophage colony-stimulating factor in CSF of VD and VE patients, suggesting that most of immune markers depend on vascular lesions, while only IL-6 was related to dementia. In VD patients, the severity of dementia as defined by the Mini-Mental Status Test or Cambridge Cognitive Examination battery test was significantly correlated with the levels of IL-8 (CSF) and macrophage inflammatory protein 1 beta (serum and CSF). Additionally, in CSF of VD patients, our data revealed a correlation between immune and neurodegenerative marker proteins. Both indicate an association of neuroinflammation and cognitive decline. Levels of PrPC were regulated differentially in VD and VE patients compared with Alzheimer's disease patients and controls. Moreover, we observed a significant negative correlation between cytokine levels and PrPC in VD patients in CSF and serum, as well as a correlation between PrPC expression with levels of neurodegenerative marker proteins in CSF (in VD and VE patients). Our data suggest that immunological modifiers play a role in VD and VE patients and provide evidence for an association of PrPC with immune and neurodegenerative markers.