Browsing by Author "Lin, Qixiang"

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    Frontal Metabolites and Alzheimer’s Disease Biomarkers in Healthy Older Women and Women Diagnosed with Mild Cognitive Impairment
    (IOS Press, 2022) Hone-Blanchet, Antoine; Bohsali, Anastasia; Krishnamurthy, Lisa C.; Shahid, Salman S.; Lin, Qixiang; Zhao, Liping; Bisht, Aditya S.; John, Samantha E.; Loring, David; Goldstein, Felicia; Levey, Allan; Lah, James; Qiu, Deqiang; Crosson, Bruce; Radiology and Imaging Sciences, School of Medicine
    Background: Women account for two thirds of the prevalence and incidence of Alzheimer's disease (AD) and mild cognitive impairment (MCI). Evidence suggest that sex may differently influence the expression of proteins amyloid-beta (Aβ1-42) and tau, for which early detection is crucial in prevention of the disease. Objective: We investigated the effect of aging and cerebrospinal fluid (CSF) levels of Aβ1-42 and tau on frontal metabolites measured with proton magnetic resonance spectroscopy (MRS) in a cohort of cognitively normal older women and women with MCI. Methods: 3T single-voxel MRS was performed on the medial frontal cortex, using Point Resolved Spectroscopy (PRESS) and Mescher-Garwood Point Resolved Spectroscopy (MEGA-PRESS) in 120 women (age range 50-85). CSF samples of Aβ1-42 and tau and scores of general cognition were also obtained. Results: Levels of frontal gamma aminobutyric acid (GABA+) were predicted by age, independently of disease and CSF biomarkers. Importantly, levels of GABA+ were reduced in MCI patients. Additionally, we found that levels of N-acetylaspartate relative to myo-inositol (tNAA/mI) predicted cognition in MCI patients only and were not related to CSF biomarkers. Conclusion: This study is the first to demonstrate a strong association between frontal GABA+ levels and neurological aging in a sample consisting exclusively of healthy older women with various levels of CSF tau and Aβ1-42 and women with MCI. Importantly, our results show no correlation between CSF biomarkers and MRS metabolites in this sample.
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    Multimodal magnetic resonance imaging reveals distinct sensitivity of hippocampal subfields in asymptomatic stage of Alzheimer's disease
    (Frontiers Media, 2022-08-12) Wu, Junjie; Shahid, Syed S.; Lin, Qixiang; Hone-Blanchet, Antoine; Smith, Jeremy L.; Risk, Benjamin B.; Bisht, Aditya S.; Loring, David W.; Goldstein, Felicia C.; Levey, Allan I.; Lah, James J.; Qiu, Deqiang; Radiology and Imaging Sciences, School of Medicine
    While hippocampal atrophy and its regional susceptibility to Alzheimer’s disease (AD) are well reported at late stages of AD, studies of the asymptomatic stage of AD are limited but could elucidate early stage pathophysiology as well as provide predictive biomarkers. In this study, we performed multi-modal magnetic resonance imaging (MRI) to estimate morphometry, functional connectivity, and tissue microstructure of hippocampal subfields in cognitively normal adults including those with asymptomatic AD. High-resolution resting-state functional, diffusion and structural MRI, cerebral spinal fluid (CSF), and neuropsychological evaluations were performed in healthy young adults (HY: n = 40) and healthy older adults with negative (HO−: n = 47) and positive (HO+ : n = 25) CSF biomarkers of AD. Morphometry, functional connectivity, and tissue microstructure were estimated from the structural, functional, and diffusion MRI images, respectively. Our results indicated that normal aging affected morphometry, connectivity, and microstructure in all hippocampal subfields, while the subiculum and CA1-3 demonstrated the greatest sensitivity to asymptomatic AD pathology. Tau, rather than amyloid-β, was closely associated with imaging-derived synaptic and microstructural measures. Microstructural metrics were significantly associated with neuropsychological assessments. These findings suggest that the subiculum and CA1-3 are the most vulnerable in asymptomatic AD and tau level is driving these early changes.
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    Relationships between frontal metabolites and Alzheimer's disease biomarkers in cognitively normal older adults
    (Elsevier, 2022) Hone-Blanchet, Antoine; Bohsali, Anastasia; Krishnamurthy, Lisa C.; Shahid, Salman; Lin, Qixiang; Zhao, Liping; Loring, David; Goldstein, Felicia; John, Samantha E.; Fleischer, Candace C.; Levey, Allan; Lah, James; Qiu, Deqiang; Crosson, Bruce; Radiology and Imaging Sciences, School of Medicine
    Elevated expression of β-amyloid (Aβ1-42) and tau are considered risk-factors for Alzheimer's disease in healthy older adults. We investigated the effect of aging and cerebrospinal fluid levels of Aβ1-42 and tau on 1) frontal metabolites measured with proton magnetic resonance spectroscopy (MRS) and 2) cognition in cognitively normal older adults (n = 144; age range 50-85). Levels of frontal gamma aminobutyric acid (GABA+) and myo-inositol relative to creatine (mI/tCr) were predicted by age. Levels of GABA+ predicted cognitive performance better than mI/tCr. Additionally, we found that frontal levels of n-acetylaspartate relative to creatine (tNAA/tCr) were predicted by levels of t-tau. In cognitively normal older adults, levels of frontal GABA+ and mI/tCr are predicted by aging, with levels of GABA+ decreasing with age and the opposite for mI/tCr. These results suggest that age- and biomarker-related changes in brain metabolites are not only located in the posterior cortex as suggested by previous studies and further demonstrate that MRS is a viable tool in the study of aging and biomarkers associated with pathological aging and Alzheimer's disease.