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18 Regional patterns of mitochondrial function using phosphorus magnetic resonance spectroscopy in older adults at-risk for Alzheimer’s disease.
- Francesca V Lopez, Andrew O’Shea, Stacey Alvarez-Alvarado, Adrianna Ratajska, Lauren Kenney, Rachel Schade, Katie Rodriguez, Alyssa Ray, Rebecca O’Connell, Lauren Santos, Emily Van Etten, Hyun Song, Emma Armstrong, Tiffany Gin, Zhiguang Huo, Gene Alexander, Adam J Woods, Dawn Bowers
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 331-332
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- Article
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Objective:
The brain is reliant on mitochondria to carry out a host of vital cellular functions (e.g., energy metabolism, respiration, apoptosis) to maintain neuronal integrity. Clinically relevant, dysfunctional mitochondria have been implicated as central to the pathogenesis of Alzheimer’s disease (AD). Phosphorous magnetic resonance spectroscopy (31p MRS) is a non-invasive and powerful method for examining in vivo mitochondrial function via high energy phosphates and phospholipid metabolism ratios. At least one prior 31p MRS study found temporal-frontal differences for high energy phosphates in persons with mild AD. The goal of the current study was to examine regional (i.e., frontal, temporal) 31p MRS ratios of mitochondrial function in a sample of older adults at-risk for AD. Given the high energy consumption in temporal lobes (i.e., hippocampus) and preferential age-related changes in frontal structure-function, we predicted 31p MRS ratios of mitochondrial function would be greater in temporal as compared to frontal regions.
Participants and Methods:The current study leveraged baseline neuroimaging data from an ongoing multisite study at the University of Florida and University of Arizona. Participants were older adults with memory complaints and a first-degree family history of AD [N = 70; mean [M] age [years] = 70.9, standard deviation [SD] =5.1; M education [years] = 16.2, SD = 2.2; M MoCA = 26.5, SD = 2.4; 61.4% female; 91.5% non-latinx white]. To achieve optimal sensitivity, we used a single voxel method to examine 31p MRS ratios (bilateral prefrontal and left temporal). Mitochondrial function was estimated by computing 5 ratios for each voxel: summed adenosine triphosphate to total pooled phosphorous (ATP/TP; momentary energy), ATP to inorganic phosphate (ATP/Pi; energy consumption), phosphocreatine to ATP (PCr/ATP; energy reserve), phosphocreatine to inorganic phosphate (PCr/Pi; oxidative phosphorylation), and phosphomonoesters to phosphodiesters (PME/PDE; cellular membrane turnover rate). All ratios were corrected for voxel size and cerebrospinal fluid fraction. Separate repeated measures analyses of variance controlling for scanner site differences (RM ANCOVAs) were performed.
Results:31p MRS ratios were unrelated to demographic characteristics and were not included as additional covariates in analyses. Results of separate RM ANCOVAs revealed all 31p MRS ratios of mitochondrial function were greater in left temporal relative to bilateral prefrontal voxel: ATP/TP (p < .001), ATP/Pi (p = .001), PCr/ATP (p = .004), PCr/Pi (p = .004), and PME/PDE (p = .017). Effect sizes (partial eta squared) ranged from 0.6-.20.
Conclusions:Consistent and extending one prior study, all 31p MRS ratios of mitochondrial function were greater in temporal as compared to frontal regions in older adults at-risk for AD. This may in part be related to the intrinsically high metabolic rate of the temporal region and preferential age-related changes in frontal structure-function. Alternatively, findings may reflect the influence of unaccounted factors (e.g., hemodynamics, auditory stimulation). Longitudinal study designs may inform whether patterns of mitochondrial function across different brain regions are present early in development, occur across the lifespan, or some combination. In turn, this may inform future studies examining differences in mitochondrial function (as measured using 31p MRS) in AD.
11 - Choosing treatments and the role of shared decision-making
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- By <span class='sc'>France</span> <span class='sc'>Légaré</span>, <span class='sc'>Martin</span> <span class='sc'>Härter</span>, <span class='sc'>Anne M.</span> <span class='sc'>Stiggelbout</span>, <span class='sc'>Richard</span> <span class='sc'>Thomson</span>, <span class='sc'>Dawn</span> <span class='sc'>Stacey</span>
- Edited by Ellen Nolte, London School of Hygiene and Tropical Medicine, Sherry Merkur, Anders Anell, Lunds Universitet, Sweden
- Assisted by Jonathan North
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- Book:
- Achieving Person-Centred Health Systems
- Published online:
- 10 July 2020
- Print publication:
- 06 August 2020, pp 283-316
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Summary
In 2015 people in OECD countries consulted a medical practitioner between two and sixteen times (OECD, 2015). These care-seekers were once expected to go along with whatever the doctor decided was best, but this has been slowly changing since the 1970s. As highlighted in Chapter 2 of this book, growing awareness of the limits of medical interventions and of the lack of control over decisions about one’s own care (Illich, 1975) led to calls for equality between the patient and the health professional towards establishing a partnership for making decisions and determining the direction of care.
The notion of a more participatory approach to informed decision-making was first proposed by Robert Veatch in 1972, who suggested the idea of “sharing of decision-making” (Veatch, 1972). Evidence was accumulating that where doctors and patients agreed on the problem, outcomes were better (Starfield et al., 1979).