Introduction: To investigate the associations of metabotropic glutamate receptor 5 (mGluR5) with tau deposition and cognitive ability in patients with early Alzheimer's disease (AD).
Methods: Twenty-six cognitively impaired (CI) and 14 cognitively unimpaired (CU) individuals underwent mGluR5 positron emission tomography (PET) ([F]PSS232), amyloid PET ([F]florbetapir), and tau PET ([F]MK6240), and neuropsychological assessment. The relationships among mGluR5 availability, tau deposition, and neuropsychological assessment were analyzed using Spearman's correlation and mediation analyses.
Results: CI patients had lower mGluR5 in the hippocampus than CU (standardized uptake value ratio [SUVr]: 2.03 ± 0.25 vs 1.79 ± 0.17, p = 0.003). Hippocampal mGluR5 was negatively associated with hippocampal tau deposition (r = -.46, p = 0.003) and positively associated with cognitive performance, but only in women. Hippocampal tau deposition mediated the effect of mGluR5 on cognitive performance.
Discussion: Reduced hippocampal mGluR5 is negatively related with tau deposition in most cortical regions and positively associated with cognitive performance, making it a promising biomarker for AD diagnosis and therapy.
Highlights: Cognitively impaired (CI) patients exhibited lower metabotropic glutamate receptor 5 (mGluR5) availability in the hippocampus than cognitively unimpaired (CU) subjects. Hippocampal mGluR5 availability was negatively associated with tau deposition in widespread cortex. Hippocampal mGluR5 availability was positively associated with cognitive performance. The close association of mGluR5 with tau and cognition performance exists only in females. Tau pathology mediated the relationship between mGluR5 availability and cognition.
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http://dx.doi.org/10.1002/alz.70004 | DOI Listing |
J Cereb Blood Flow Metab
March 2025
Department of Radiology, Juntendo University Graduate School of Medicine, Juntendo University, Tokyo, Japan.
The Alzheimer's disease (AD) continuum is characterized by amyloid and tau protein deposition, which is partly attributable to the dysfunction of the brain clearance system. However, the specific phase in the AD continuum wherein aberrant clearance is present remains unclear. This study aimed to assess noninvasive magnetic resonance imaging (MRI) indices related to brain clearance functions, such as choroid plexus volume (CPV), lateral ventricular volume (LVV), and the index of diffusivity along the perivascular space (ALPS index), across the Alzheimer's disease (AD) spectrum.
View Article and Find Full Text PDFInt J Mol Sci
February 2025
Department and Clinic of Psychiatry, Wroclaw Medical University, 50-367 Wroclaw, Poland.
Alzheimer's disease (AD) is the most common cause of dementia worldwide. Pathological deposits of neurotoxin proteins within the brain, such as amyloid-β and hyperphosphorylated tau tangles, are prominent features in AD. The prion protein (PrP) is involved in neurodegeneration via its conversion from the normal cellular form (PrPC) to the infection prion protein scrapie (PrPSc) form.
View Article and Find Full Text PDFFree Neuropathol
January 2025
Department of Laboratory Medicine, St. Michael's Hospital, Unity Health & Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
There is considerable evidence for a role for metabolic dysregulation, including disordered purine nucleotide metabolism, in the pathogenesis of Alzheimer's disease (AD). Purine nucleotide synthesis in the brain is regulated with high fidelity to co-ordinate supply with demand. The assembly of some purine biosynthetic enzymes into linear filamentous aggregates called "cytoophidia" (Gk.
View Article and Find Full Text PDFProg Neurobiol
March 2025
Mitchell Center for Neurodegenerative Diseases, The University of Texas Medical Branch, 301 University Blvd, Galveston, Texas 77555, USA; Departments of Neurology, The University of Texas Medical Branch, 301 University Blvd, Galveston, Texas 77555, USA. Electronic address:
Alzheimer's disease (AD) is marked by cytoplasmic proteinopathies, primarily involving misfolded Tau protein. Pathogenic Tau species, such as soluble oligomers and fibrils, disrupt RNA metabolism, though the mechanisms are unclear. Recent research indicates that RNA has a crucial role in Tau aggregation.
View Article and Find Full Text PDFJAMA Neurol
March 2025
Eli Lilly and Company, Indianapolis, Indiana.
Importance: Amyloid-related imaging abnormalities (ARIA) are the major adverse event associated with amyloid-targeting immunotherapy. Identifying clinical features and individual risk factors for ARIA could facilitate effective prediction and prevention strategies.
Objective: To characterize ARIA in participants treated with donanemab.
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