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Abstract: Studies suggest that inflammation is involved in the neurodegenerative cascade of dementias. Immunological mechanisms may be part of the pathophysiological process in frontotemporal dementia (FTD), but up till now only vague evidence of such mechanisms has been presented. The B7- CD28/CTLA-4 pathway is an important immunological signaling pathway involved in modulation of T cell activation. The aim of this study was to compare the expression of molecules associated with co-stimulatory signaling in peripheral blood mononuclear cells (PBMC) of FTD to Alzheimer disease (AD) and control groups. Our results confirm the previous demonstrated increased expression of CD80 in CD14+ Alzheimer patients T cells but show, for the first time, a reduction in the expression of CTLA-4 in CD4+ FTD cells. As CTLA-4 is the most potent negative regulators of T-cell activation we speculated that peripheral T lymphocytes in FTD are more activated and this could be involved in the neurodegeneration observed in this dementia. [Copyright &y& Elsevier]

Objectives The in vitro effect of a vitamin complex in generating and reducing oxidative species in peripheral blood mononuclear cells (PBMNC) and plasma of patients with Alzheimer's disease (AD) and healthy subjects (HS) was evaluated. Methods Two concentrations of a vitamin complex ([A] and [20A]) with ascorbic acid, alpha-tocopherol, and beta-carotene were incubated with either mononuclear cells or plasma. The generation of oxidizing species was measured in a luminol-dependent chemiluminescence assay and the reducing response by the MTT dye reduction assay. The levels of cytokines (interleukin [IL]-1β, IL-6, and IL-4) were measured by sandwich enzyme-linked immunosorbent assay. Results Our results demonstrated that the increase in the vitamin complex concentration reduced the reactive oxygen species (ROS) production and enhanced cellular reduction capacity in cells of AD patients in concentration [20A]. Plasma reduction capacity rose significantly for both groups (AD and HS). Concentration [A] did not alter the IL-1β production, increased IL-4 production in both groups and lowered IL-6 production in AD cells. Concentration [20A] increased pro-inflammatory cytokines (IL-1β and IL-6) and decreased IL-4 production by PBMNC of HS leading to a pro-inflammatory status. Discussion The antioxidant vitamin complex was effective in reducing oxidative stress in PBMNC of AD patients by lowering ROS production, improving cellular antioxidant capacities and modifying cytokine induced inflammation. [ABSTRACT FROM AUTHOR]

Abstract: Alzheimer''s dementia (AD) is a degenerative brain disorder characterized mainly by cholinergic failure, but other neuro-transmitters are also deficient especially at late stages of the disease. Misfolded β-amyloid peptide has been identified as a causative agent, however inflammatory changes also play a pivotal role. Even though the most prominent pathology is seen in the cognitive functions, specific abnormalities of the central nervous system (CNS) are also reflected in the periphery, particularly in the immune responses of the body. The aim of this study was to characterize the dopaminergic and serotonergic systems in AD, which are also markedly disrupted along with the hallmark acetyl-choline dysfunction. Peripheral blood mono-nuclear cells (PBMCs) from demented patients were judged against comparison groups including individuals with late-onset depression (LOD), as well as non-demented and non-depressed subjects. Cellular sub-populations were evaluated by mono-clonal antibodies against various cell surface receptors: CD4/CD8 (T-lymphocytes), CD19 (B-lymphocytes), CD14 (monocytes), and CD56 (natural-killer (NK)-cells). The expressions of dopamine D3 and D4, as well as serotonin 5-HT1A, 5-HT2A, 5-HT2B and 5-HT2C were also assessed. There were no significant differences among the study groups with respect to the frequency of the cellular sub-types, however a unique profound increase in 5-HT2C receptor exclusively in NK-cells was observed in AD. The disease-specific expression of 5-HT2C, as well as the NK-cell cyto-toxicity, has been linked with cognitive derangement in dementia. These changes not only corroborate the existence of bi-directional communication between the immune system and the CNS, but also elucidate the role of inflammatory activity in AD pathology, and may serve as potential biomarkers for less invasive and early diagnostic purposes as well. [Copyright &y& Elsevier]