Accelerometer-based analysis of gait and prediction of fall risk in older adults

Falls are the most common cause of injury in older adults with two-thirds of individuals over the age of 65 falling at least once a year. It is well known that falls represent a significant challenge to preserving quality of life as we age, but current clinical methods of screening for fall risk remain insufficient to prevent falls. This thesis summarizes the development of a modern approach to fall risk analysis and fall prevention through the use of hip-mounted triaxial accelerometers to passively monitor gait quality in free-living environments and predict risk of future falls. Data from over 4000 individuals enrolled in the Women Health Initiative’s Objective Physical Activity and Cardiovascular Health study were used for the development of an activity recognition pipeline for extraction of free-living walking bouts measured by accelerometers. A variety of measures of gait were computed from walking bout data and used as input to train statistical models which analyze gait to predict fall risk and future falls. Results suggest that hip-mounted accelerometers are able to capture free-living gait patterns which can be used to predict measures of fall risk and physical function such as the Short Physical Performance Battery. However, these same measures of gait prove to be insufficient for direct prediction future falls

Association of MAPT haplotypes with Alzheimer’s disease risk and MAPT brain gene expression levels

Introduction: MAPT encodes for tau, the predominant component of neurofibrillary tangles that are neuropathological hallmarks of Alzheimer’s disease (AD). Genetic association of MAPT variants with late-onset AD (LOAD) risk has been inconsistent, although insufficient power and incomplete assessment of MAPT haplotypes may account for this. Methods: We examined the association of MAPT haplotypes with LOAD risk in more than 20,000 subjects (n-cases = 9,814, n-controls = 11,550) from Mayo Clinic (n-cases = 2,052, n-controls = 3,406) and the Alzheimer’s Disease Genetics Consortium (ADGC, n-cases = 7,762, n-controls = 8,144). We also assessed associations with brain MAPT gene expression levels measured in the cerebellum (n = 197) and temporal cortex (n = 202) of LOAD subjects. Six single nucleotide polymorphisms (SNPs) which tag MAPT haplotypes with frequencies greater than 1% were evaluated. Results: H2-haplotype tagging rs8070723-G allele associated with reduced risk of LOAD (odds ratio, OR = 0.90, 95% confidence interval, CI = 0.85-0.95, p = 5.2E-05) with consistent results in the Mayo (OR = 0.81, p = 7.0E-04) and ADGC (OR = 0.89, p = 1.26E-04) cohorts. rs3785883-A allele was also nominally significantly associated with LOAD risk (OR = 1.06, 95% CI = 1.01-1.13, p = 0.034). Haplotype analysis revealed significant global association with LOAD risk in the combined cohort (p = 0.033), with significant association of the H2 haplotype with reduced risk of LOAD as expected (p = 1.53E-04) and suggestive association with additional haplotypes. MAPT SNPs and haplotypes also associated with brain MAPT levels in the cerebellum and temporal cortex of AD subjects with the strongest associations observed for the H2 haplotype and reduced brain MAPT levels (β = -0.16 to -0.20, p = 1.0E-03 to 3.0E-03). Conclusions: These results confirm the previously reported MAPT H2 associations with LOAD risk in two large series, that this haplotype has the strongest effect on brain MAPT expression amongst those tested and identify additional haplotypes with suggestive associations, which require replication in independent series. These biologically congruent results provide compelling evidence to screen the MAPT region for regulatory variants which confer LOAD risk by influencing its brain gene expression

Accelerometer-based analysis of gait and prediction of fall risk in older adults

Falls are the most common cause of injury in older adults with two-thirds of individuals over the age of 65 falling at least once a year. It is well known that falls represent a significant challenge to preserving quality of life as we age, but current clinical methods of screening for fall risk remain insufficient to prevent falls. This thesis summarizes the development of a modern approach to fall risk analysis and fall prevention through the use of hip-mounted triaxial accelerometers to passively monitor gait quality in free-living environments and predict risk of future falls. Data from over 4000 individuals enrolled in the Women Health Initiative’s Objective Physical Activity and Cardiovascular Health study were used for the development of an activity recognition pipeline for extraction of free-living walking bouts measured by accelerometers. A variety of measures of gait were computed from walking bout data and used as input to train statistical models which analyze gait to predict fall risk and future falls. Results suggest that hip-mounted accelerometers are able to capture free-living gait patterns which can be used to predict measures of fall risk and physical function such as the Short Physical Performance Battery. However, these same measures of gait prove to be insufficient for direct prediction future falls.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste

Effects of sex and APOE on Parkinson’s Disease-related cognitive decline

Introduction. Cognitive impairment is common in Parkinson’s Disease, but the impact of predictive factors on incidence and rate of cognitive decline is incompletely understood. We aimed to determine the effects of sex and APOE allele status on cognitive performance in patients with Parkinson’s Disease (PD).Material and methods. We conducted a retrospective analysis of 325 clinically diagnosed PD patients who underwent one or more cognitive screenings with a Mini-Mental Status Examination (MMSE) or Mattis Dementia Rating Scale (DRS-2). We used proportional odds regression models to estimate odds ratios for higher versus lower cognitive scores in association with age, sex, education, disease duration, and APOE allele status.Results. Higher cognitive scores were independently associated with female sex on the MMSE (OR 2.43; 95% CI 1.14, 5.14) and DRS-2 total (OR 4.14; 95% CI 2.01, 8.53). APOE ε4 dose was associated with lower DRS-2 totals (OR 0.42; 95% CI 0.22, 0.81), but there was no evidence of association with MMSE. Higher education level was also associated with higher scores on the MMSE (OR 1.22; 95% CI 1.07, 1.38) and DRS-2 total (OR 1.31; 95% CI 1.15, 1.50). Disease duration was not associated with cognitive performance on any measure when adjusting for age.Conclusion. Male sex and APOE ε4, along with age and lower education level, were associated with poorer cognitive performance among a population of predominantly non-demented PD patients

Deletion of Abi3/Gngt2 influences age-progressive amyloid β and tau pathologies in distinctive ways.

BACKGROUND: The S209F variant of Abelson Interactor Protein 3 (ABI3) increases risk for Alzheimer\u27s disease (AD), but little is known about its function in relation to AD pathogenesis. METHODS: Here, we use a mouse model that is deficient in Abi3 locus to study how the loss of function of Abi3 impacts two cardinal neuropathological hallmarks of AD-amyloid β plaques and tau pathology. Our study employs extensive neuropathological and transcriptomic characterization using transgenic mouse models and adeno-associated virus-mediated gene targeting strategies. RESULTS: Analysis of bulk RNAseq data confirmed age-progressive increase in Abi3 levels in rodent models of AD-type amyloidosis and upregulation in AD patients relative to healthy controls. Using RNAscope in situ hybridization, we localized the cellular distribution of Abi3 in mouse and human brains, finding that Abi3 is expressed in both microglial and non-microglial cells. Next, we evaluated Abi3 CONCLUSIONS: These data provide an important experimental framework for understanding the role of Abi3-Gngt2 function and early inflammatory gliosis in AD. Our studies also demonstrate that inflammatory gliosis could have opposing effects on amyloid and tau pathology, highlighting the unpredictability of targeting immune pathways in AD

Cross species systems biology discovers glial DDR2, STOM, and KANK2 as therapeutic targets in progressive supranuclear palsy

Abstract Progressive supranuclear palsy (PSP) is a neurodegenerative parkinsonian disorder characterized by cell-type-specific tau lesions in neurons and glia. Prior work uncovered transcriptome changes in human PSP brains, although their cell-specificity is unknown. Further, systematic data integration and experimental validation platforms to prioritize brain transcriptional perturbations as therapeutic targets in PSP are currently lacking. In this study, we combine bulk tissue (n = 408) and single nucleus RNAseq (n = 34) data from PSP and control brains with transcriptome data from a mouse tauopathy and experimental validations in Drosophila tau models for systematic discovery of high-confidence expression changes in PSP with therapeutic potential. We discover, replicate, and annotate thousands of differentially expressed genes in PSP, many of which reside in glia-enriched co-expression modules and cells. We prioritize DDR2, STOM, and KANK2 as promising therapeutic targets in PSP with striking cross-species validations. We share our findings and data via our interactive application tool PSP RNAseq Atlas ( https://rtools.mayo.edu/PSP_RNAseq_Atlas/ ). Our findings reveal robust glial transcriptome changes in PSP, provide a cross-species systems biology approach, and a tool for therapeutic target discoveries in PSP with potential application in other neurodegenerative diseases

Genome-wide association study of brain biochemical phenotypes reveals distinct genetic architecture of Alzheimer's disease related proteins

BACKGROUND: Alzheimer’s disease (AD) is neuropathologically characterized by amyloid-beta (Aβ) plaques and neurofibrillary tangles. The main protein components of these hallmarks include Aβ40, Aβ42, tau, phosphor-tau, and APOE. We hypothesize that genetic variants influence the levels and solubility of these AD-related proteins in the brain; identifying these may provide key insights into disease pathogenesis. METHODS: Genome-wide genotypes were collected from 441 AD cases, imputed to the haplotype reference consortium (HRC) panel, and filtered for quality and frequency. Temporal cortex levels of five AD-related proteins from three fractions, buffer-soluble (TBS), detergent-soluble (Triton-X = TX), and insoluble (Formic acid = FA), were available for these same individuals. Variants were tested for association with each quantitative biochemical measure using linear regression, and GSA-SNP2 was used to identify enriched Gene Ontology (GO) terms. Implicated variants and genes were further assessed for association with other relevant variables. RESULTS: We identified genome-wide significant associations at seven novel loci and the APOE locus. Genes and variants at these loci also associate with multiple AD-related measures, regulate gene expression, have cell-type specific enrichment, and roles in brain health and other neuropsychiatric diseases. Pathway analysis identified significant enrichment of shared and distinct biological pathways. CONCLUSIONS: Although all biochemical measures tested reflect proteins core to AD pathology, our results strongly suggest that each have unique genetic architecture and biological pathways that influence their specific biochemical states in the brain. Our novel approach of deep brain biochemical endophenotype GWAS has implications for pathophysiology of proteostasis in AD that can guide therapeutic discovery efforts focused on these proteins. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13024-022-00592-2