Alzheimer Diseases

Improvement of spatial learning and memory deficits by intranasal administration of human olfactory ecto-mesenchymal stem cells in an Alzheimer's disease rat model

Mesenchymal stem cells therapy provides a new perspective of therapeutic approaches in the treatment of neurodegenerative diseases. The present study aimed to investigate the effects of intranasally transplanted human "olfactory ecto-mesenchymal stem cells" (OE-MSCs) in Alzheimer's disease (AD) rats. In this study, we isolated OE-MSCs from human olfactory lamina propria and phenotypically characterized them using immunocytochemistry and flow cytometry. The undifferentiated OE-MSCs were transplanted either by intranasal (IN) or intrahippocampal (IH) injection to rat models of AD, which were induced by injecting amyloid-beta (Aβ) intrahippocampally. Behavioral, histological, and molecular assessments were performed after a three-month recovery period. Based on the results, intranasal administration of OE-MSCs significantly reduced Aβ accumulation and neuronal loss, improved learning and memory impairments, and increased levels of BDNF (brain-derived neurotrophic factor) and NMDAR (N-methyl-D-Aspartate receptors) in the AD rat model. These changes were more significant in animals who received OE-MSCs by intranasal injection. The results of this study suggest that OE-MSCs have the potential to enhance cognitive function in AD, possibly mediated by BDNF and the NMDA receptors.

Beta-Amyloid-Dependent miRNAs as Circulating Biomarkers in Alzheimer's Disease: a Preliminary Report

MicroRNAs (miRNAs) are considered among the most reliable biomarkers to diagnose and predict Alzheimer's disease (AD), due to their regulatory nature. The main goal of this study was to evaluate the expression of miR4422 and miR3714, as the main regulators of GSAP and BACE1 expression, in AD patients compared with healthy subjects. Twenty patients with a mild to moderate AD (58-71 years old) and 15 healthy subjects (58-73 years old) participated in this study. The expression levels of miR4422 and miR3714 as the target genes and 5S rRNA and miRlet7a-5p as the reference genes were measured in the two groups. To compare the expression between the case and the control groups, the t test or the Wilcoxon test was used, based on the data distribution patterns. The efficiencies of amplification of the miR4422, miR3714, 5S rRNA, and miRlet7a-5p genes all were in the acceptable range. The mean miR4422-5S rRNA dCt value was significantly different between the two groups (p = 0.018). The relative fold change of the expression was 0.43. The mean miR4422-miRlet7a-5p dCt value (p = 0.41), the mean miR3714-5S rRNA dCt value (p = 0.10), and the mean miR3714-miRlet7a-5p dCt value (p = 0.063) were not significantly different between the two groups. We indicated that miR4422 could be a reliable biomarker for Alzheimer's diagnosis. It seems that the reduced expression of miR4422 that targets GSAP and BACE1 expression can lead to an increase in the formation of Aβ plaque.