Abstract
Purpose. To examine the associations among age, Apolipoprotein E (APOE) genotype, metabolic changes in the hippocampus detected by 2D 1H magnetic resonance spectroscopy (MRS), and neuropsychological measures of cognition in non-demented elders.Materials and Methods. We studied a cohort of 16 cognitively normal controls (CN) and 11 amnestic mild cognitive impairment (aMCI) patients between 66 and 88 years old who were genotyped for APOE genetic polymorphism. Measurements of 2D1H-MRS metabolites were obtained in the hippocampus region. Adjusting by age among all subjects, the association between metabolic changes and cognitive function was measured by Spearman partial rank-order correlation. The effect of APOE status was measured by separating the subjects into APOE genotype subgroups, including the APOEε4 carriers and APOEε4 non-carriers.Results. In contrast to the CN group matched with age, gender, and education, aMCI patients showed increased myo-inositol (mI)/Creatine (Cr) ratio only in the right hippocampus. No differences were noted on N-acetylaspartate (NAA)/Cr and mI/NAA from bilateral hippocampus, and so was mI/Cr ratio in left hippocampus between aMCI and CN. The mI/Cr ratio from the right hippocampus in non-demented elders was negatively correlated with Montreal Cognitive Assessment (MoCA) scores. Whether ε4 genotype or age was added as a covariate, none of the correlation effects remained significant. Additionally, adjusting for age and APOE genotype together, there was no significant correlation between them.Conclusion. Since the higher mI/Cr from the right hippocampus of the patients with aMCI than those from CN, the mI/Cr could be a more specific predictor of general cognitive function in aMCI patients. There is an association between higher mI/Cr in right hippocampus and worse cognitive function for the non-demented older adults, and the correlation could be modified by APOE status and age. That provided a window on objectively understanding the mechanism between the brain metabolites and the influence factors in non-demented elders.
Highlights
The proton magnetic resonance spectroscopy (1H MRS) is unique among diagnostic imaging modalities because the signals from several different metabolites are measured
There was no correlation between cognitive function and 1H-MRS metabolite ratios in both APOEε4 carriers and APOEε4 non-carriers after controlling for age, indicating that the Apolipoprotein E (APOE) status and age might influence the correlation between cognition and 1H-MRS metabolite ratios as shown in Findings of this study indicated that the glial activity marker mI/Cr from the right hippocampus increased in patients with amnestic mild cognitive impairment (aMCI) compared with those from normal elderly
There is an association between higher mI/Cr in right hippocampus and worse cognitive function in non-demented older adults and this relationship could be modified by APOE status and age
Summary
The proton magnetic resonance spectroscopy (1H MRS) is unique among diagnostic imaging modalities because the signals from several different metabolites are measured. It is a potential metabolic marker in Alzheimer’s disease (AD) for both early diagnoses and evaluating treatment effects (Graff-Radford & Kantarci, 2013; Murray et al, 2014; Tumati, Martens & Aleman, 2013). The mI/Cr ratio is associated with glia and elevated levels with glial proliferation. Glial and microglial activity raises the possibility that elevated mI represents inflammation which is an early event in the evolution of AD pathology (Graff-Radford & Kantarci, 2013)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
