Systemic Inflammation and Multimodal Biomarkers in Amnestic Mild Cognitive Impairment and Alzheimer's Disease.

There is increasing evidence suggesting that one of the most relevant pathophysiological features of Alzheimer's disease (AD) is neuroinflammation, which plays an important role in the production and regulation of AD-related proteins (amyloid beta (Aß) and Tau) and exacerbates AD pathology. Neuroinflammation can also be induced by systemic influences (factors from outside the central nervous system). However, the role of systemic inflammation in AD pathophysiology is much less understood. Thus, our main objective in this study was to verify whether the presence of serum cytokines (IL-1ß, IL-6, IL-10, IL-12, and TNF-α) affects different AD biomarkers: Aß1-42 and Tau protein levels, hippocampal volumes (HV), and default mode network functional connectivity (DMN FC) in healthy elderly controls, amnestic mild cognitive impairment (aMCI) patients due to AD, and mild AD patients. To accomplish this, we acquired 3-T MRI, blood, and cerebrospinal fluid (CSF) samples from 42 healthy controls, 55 aMCI patients due to AD, and 33 mild AD patients. Comparing the groups, we found that the mild AD patients presented smaller HV, disrupted DMN FC, and proportionally less IL-1ß than the controls. The aMCI patients only differed from the controls in DMN FC. In intra-group comparison, aMCI and mild AD with detectable levels of cytokines (TNF-α, IL-1ß, IL-10, and IL-12) had decreased DMN FC. On the other hand, patients with detectable levels of IL-10 and IL-12 presented a more favorable AD biomarkers profile (larger HV, more CSF Aß1-42, and less p-Tau), indicating a possible protective role of these ILs. Our findings indicate a possible relationship between systemic inflammation with DMN FC disruption, hippocampal atrophy, and CSF protein levels in the subjects with mild AD and aMCI.

5-hydroxytryptamine1A receptor density in the hippocampus of patients with temporal lobe epilepsy is associated with disease duration.

BACKGROUND AND PURPOSE: To date, no study has evaluated the association between serotonin receptor density and clinical variables in patients with temporal lobe epilepsy caused by hippocampal sclerosis (TLE-HS) using hippocampal tissue. We evaluated 5-hydroxytryptamine1A receptor (5-HT1AR) density in hippocampal tissue from patients with TLE-HS. METHODS: We analyzed the hippocampal tissue of 34 patients with pharmacoresistant unilateral TLE-HS. 5-HT1AR density was measured using semiquantitative western blotting. RESULTS: There was an association between higher density of 5-HT1AR and longer duration of epilepsy (Spearman correlation: P = 0.040; generalized linear model: P = 0.026). CONCLUSIONS: This study demonstrated that hippocampal 5-HT1AR density is associated with epilepsy duration in patients with TLE-HS. The authors postulate that this may represent a potential regulatory enhancement of endogenous serotonergic neurotransmission in response to prolonged and enduring epileptiform activity in the hippocampal tissue of patients with pharmacoresistant TLE-HS.

Increased iPLA2 activity and levels of phosphorylated GSK3B in platelets are associated with donepezil treatment in Alzheimer's disease patients.

Reduced phospholipase A2 (PLA2) activity and increased phosphorylation of glycogen synthase kinase 3B (GSK3B) participate in the production of beta-amyloid plaques and of neurofibrillary tangles, which are two neuropathological hallmarks of Alzheimer's disease (AD). Experimental evidences suggest a neuroprotective effect of the cholinesterase inhibitor donepezil in the treatment the disease. The aims of the present study were to evaluate in AD patients the effects of treatment with donepezil on PLA2 activity and GSK3B level. Thirty patients with AD were treated during 6 months with 10 mg daily of donepezil. Radio-enzymatic assays were used to measure PLA2 activity and Elisa assays for GSK3B level, both in platelets. Before treatment and after 3 and 6 months on donepezil, AD patients underwent a cognitive assessment and platelet samples were collected. Values were compared to a healthy control group of 42 sex- and age-matched elderly individuals. Before treatment, iPLA2 activity was lower in patients with AD as compared to controls (p < 0.001). At baseline, no differences were found in GSK3B level between both groups. After 3 and 6 months of treatment, we found a significant increase in iPLA2 activity (p = 0.015 and p < 0.001, respectively). iPLA2 increment was related to the cognitive improvement during treatment (p = 0.037). After 6 months, we found an increase in phosphorylated GSK3B (p = 0.02). The present findings suggest two possible mechanisms by which donepezil delays the progression of AD. The increment of iPLA2 activity may reduce the production of beta-amyloid plaques, whereas the phosphorylation of GSK3B inactivates the enzyme, reducing thus the phosphorylation of tau protein.