Browsing by Author "Saykin, Andrew"
Now showing 1 - 10 of 20
Results Per Page
Sort Options
Item Accelerating diversity in Alzheimer's disease research by partnering with a community advisory board(Wiley, 2023-05-28) Pena-Garcia, Alex; Richards, Ralph; Richards, Mollie; Campbell, Christopher; Mosley, Hank; Asper, Joseph; Eliacin, Johanne; Polsinelli, Angelina; Apostolova, Liana; Hendrie, Hugh; Tackett, Andrew; Elliott, Caprice; Van Heiden, Sarah; Gao, Sujuan; Saykin, Andrew; Wang, Sophia; Medicine, School of MedicineIntroduction: Community advisory boards (CABs) and researcher partnerships present a promising opportunity to accelerate enrollment of underrepresented groups (URGs). We outline the framework for how the CAB and researchers at the Indiana Alzheimer's Disease Research Center (IADRC) partnered to accelerate URG participation in AD neuroimaging research. Methods: CAB and the IADRC researchers partnered to increase the CAB's impact on URG study enrollment through community and research interactions. Community interactions included the CAB collaboratively building a network of URG focused community organizations and collaborating with those URG-focused organizations to host IADRC outreach and recruitment events. Research interactions included direct impact (CAB members referring themselves or close contacts as participants) and strategic impact, mainly by the CAB working with researchers to develop and refine URG focused outreach and recruitment strategies for IADRC and affiliated studies to increase URG representation. We created a database infrastructure to measure how these interactions impacted URG study enrollment. Results: Out of the 354 URG research referrals made to the IADRC between October 2019 and December 2022, 267 referrals were directly referred by the CAB (N = 36) or from community events in which CAB members organized and/or volunteered at (N = 231). Out of these 267 referrals, 34 were enrolled in IADRC and 2 were enrolled in Indiana University Longitudinal Early Onset AD Study (IU LEADS). Of note, both studies require the prospective participants to be willing to do MRI and PET scans. As of December 2022, 30 out of the 34 enrolled participants have received a consensus diagnosis; the majority were cognitively normal (64.7%), with the remainder having mild cognitive impairment (17.6%) or early-stage AD (2.9%). Discussion: The IADRC CAB-researcher partnership had a measurable impact on the enrollment of African American/Black adults in AD neuroimaging studies. Future studies will need to test whether this conceptual model works for other sites and for other URGs.Item APOE4 Drives Impairment in Astrocyte-Neuron Coupling in Alzheimer's Disease and Works Through Mechanisms in Early Disease to Influence Pathology(2023-05) Brink, Danika Marie Tumbleson; Lamb, Bruce; Bissel, Stephanie; Herbert, Brittney-Shea; Landreth, Gary; Puntambekar, Shweta; Saykin, Andrew; Zhang, ChiAlzheimer’s disease (AD) is a neurodegenerative disorder resulting in progressive memory loss, brain atrophy, and eventual death. AD pathology is characterized by the accumulation of neurotoxic amyloid-beta (Aβ) plaques, synapse loss, neurofibrillary tangles (NFTs), and neurodegeneration. The APOE4 allele is associated with a 3-fold increased risk for AD and results in increased Aβ plaque deposition, reduced Aβ clearance, and reduced synaptic plasticity. Although APOE expression is upregulated in microglia in AD, APOE is expressed primarily by astrocytes in the CNS. It is not well understood how astrocytic APOE drives the mechanisms that result in worsened AD outcomes. Here, digital spatial profiling and bioinformatics data suggest that APOE4 causes transcriptional dysregulation in early AD and may disrupt neuronal processes via astrocytes. Whole transcriptome data from plaque and non-plaque regions in the cortices and hippocampus of 4- and 8-month-old AD model mice expressing humanized APOE4/4 or APOE3/3 (control) were analyzed. Transcriptional dysregulation was increased in APOE4/4 AD mice compared to that in APOE3/3 at 4 but not 8 months of age, suggesting that early dysregulation of APOE4-driven disease mechanisms may shape degenerative outcomes in late-stage AD. Additionally, APOE4/4 potentially functions via plaque-independent mechanisms to influence neuronal function in early AD before the onset of pathology. Single-nuclei RNA sequencing data were obtained from human post-mortem astrocytes and the bioinformatic analyses revealed a novel astrocyte subtype that highly expresses several top genes involved in functional alterations associated with APOE4, including neuronal generation, development, and differentiation, and synaptic transmission and organization. Overall, our findings indicate that APOE4 may drive degenerative outcomes through the presented astrocyte candidate pathways. These pathways represent potential targets for investigations into early intervention strategies for APOE4/4 patients.Item Assessment of Blood Biomarker Profile After Acute Concussion During Combative Training Among US Military Cadets(JAMA, 2021-02) Giza, Christopher C.; McCrea, Michael; Huber, Daniel; Cameron, Kenneth L.; Houston, Megan N.; Jackson, Jonathan C.; McGinty, Gerald; Pasquina, Paul; Broglio, Steven P.; Brooks, Alison; DiFiori, John; Duma, Stefan; Harezlak, Jaroslaw; Goldman, Joshua; Guskiewicz, Kevin; McAllister, Thomas W.; McArthur, David; Meier, Timothy B.; Mihalik, Jason P.; Nelson, Lindsay D.; Rowson, Steven; Gill, Jessica; Foroud, Tatiana; Katz, Barry; Saykin, Andrew; Campbell, Darren E.; Svoboda, Steven; Psychiatry, School of MedicineImportance: Validation of protein biomarkers for concussion diagnosis and management in military combative training is important, as these injuries occur outside of traditional health care settings and are generally difficult to diagnose. Objective: To investigate acute blood protein levels in military cadets after combative training-associated concussions. Design, setting, and participants: This multicenter prospective case-control study was part of a larger cohort study conducted by the National Collegiate Athletic Association and the US Department of Defense Concussion Assessment Research and Education (CARE) Consortium from February 20, 2015, to May 31, 2018. The study was performed among cadets from 2 CARE Consortium Advanced Research Core sites: the US Military Academy at West Point and the US Air Force Academy. Cadets who incurred concussions during combative training (concussion group) were compared with cadets who participated in the same combative training exercises but did not incur concussions (contact-control group). Clinical measures and blood sample collection occurred at baseline, the acute postinjury point (<6 hours), the 24- to 48-hour postinjury point, the asymptomatic postinjury point (defined as the point at which the cadet reported being asymptomatic and began the return-to-activity protocol), and 7 days after return to activity. Biomarker levels and estimated mean differences in biomarker levels were natural log (ln) transformed to decrease the skewness of their distributions. Data were collected from August 1, 2016, to May 31, 2018, and analyses were conducted from March 1, 2019, to January 14, 2020. Exposure: Concussion incurred during combative training. Main outcomes and measures: Proteins examined included glial fibrillary acidic protein, ubiquitin C-terminal hydrolase-L1, neurofilament light chain, and tau. Quantification was conducted using a multiplex assay (Simoa; Quanterix Corp). Clinical measures included the Sport Concussion Assessment Tool-Third Edition symptom severity evaluation, the Standardized Assessment of Concussion, the Balance Error Scoring System, and the 18-item Brief Symptom Inventory. Results: Among 103 military service academy cadets, 67 cadets incurred concussions during combative training, and 36 matched cadets who engaged in the same training exercises did not incur concussions. The mean (SD) age of cadets in the concussion group was 18.6 (1.3) years, and 40 cadets (59.7%) were male. The mean (SD) age of matched cadets in the contact-control group was 19.5 (1.3) years, and 25 cadets (69.4%) were male. Compared with cadets in the contact-control group, those in the concussion group had significant increases in glial fibrillary acidic protein (mean difference in ln values, 0.34; 95% CI, 0.18-0.50; P < .001) and ubiquitin C-terminal hydrolase-L1 (mean difference in ln values, 0.97; 95% CI, 0.44-1.50; P < .001) levels at the acute postinjury point. The glial fibrillary acidic protein level remained high in the concussion group compared with the contact-control group at the 24- to 48-hour postinjury point (mean difference in ln values, 0.22; 95% CI, 0.06-0.38; P = .007) and the asymptomatic postinjury point (mean difference in ln values, 0.21; 95% CI, 0.05-0.36; P = .01). The area under the curve for all biomarkers combined, which was used to differentiate cadets in the concussion and contact-control groups, was 0.80 (95% CI, 0.68-0.93; P < .001) at the acute postinjury point. Conclusions and relevance: This study's findings indicate that blood biomarkers have potential for use as research tools to better understand the pathobiological changes associated with concussion and to assist with injury identification and recovery from combative training-associated concussions among military service academy cadets. These results extend the previous findings of studies of collegiate athletes with sport-associated concussions.Item Brain-wide structural connectivity alterations under the control of Alzheimer risk genes(Inderscience, 2020) Yan, Jingwen; Raja V, Vinesh; Huang, Zhi; Amico, Enrico; Nho, Kwangsik; Fang, Shiaofen; Sporns, Olaf; Wu, Yu-chien; Saykin, Andrew; Goni, Joaquin; Shen, Li; BioHealth Informatics, School of Informatics and ComputingBackground: Alzheimer's disease is the most common form of brain dementia characterized by gradual loss of memory followed by further deterioration of other cognitive function. Large-scale genome-wide association studies have identified and validated more than 20 AD risk genes. However, how these genes are related to the brain-wide breakdown of structural connectivity in AD patients remains unknown. Methods: We used the genotype and DTI data in the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. After constructing the brain network for each subject, we extracted three types of link measures, including fiber anisotropy, fiber length and density. We then performed a targeted genetic association analysis of brain-wide connectivity measures using general linear regression models. Age at scan and gender were included in the regression model as covariates. For fair comparison of the genetic effect on different measures, fiber anisotropy, fiber length and density were all normalized with mean as 0 and standard deviation as one.We aim to discover the abnormal brain-wide network alterations under the control of 34 AD risk SNPs identified in previous large-scale genome-wide association studies. Results: After enforcing the stringent Bonferroni correction, rs10498633 in SLC24A4 were found to significantly associated with anisotropy, total number and length of fibers, including some connecting brain hemispheres. With a lower level of significance at 5e-6, we observed significant genetic effect of SNPs in APOE, ABCA7, EPHA1 and CASS4 on various brain connectivity measures.Item Broad phenotype of cysteine-altering NOTCH3 variants in UK Biobank(Wolters Kluwer, 2020-09-29) Rutten, Julie W.; Hack, Remco J.; Duering, Marco; Gravesteijn, Gido; Dauwerse, Johannes G.; Overzier, Maurice; van den Akker, Erik B.; Slagboom, Eline; Holstege, Henne; Nho, Kwangsik; Saykin, Andrew; Dichgans, Martin; Malik, Rainer; Lesnik Oberstein, Saskia A.J.; BioHealth Informatics, School of Informatics and ComputingObjective To determine the small vessel disease spectrum associated with cysteine-altering NOTCH3 variants in community-dwelling individuals by analyzing the clinical and neuroimaging features of UK Biobank participants harboring such variants. Methods The exome and genome sequencing datasets of the UK Biobank (n = 50,000) and cohorts of cognitively healthy elderly (n = 751) were queried for cysteine-altering NOTCH3 variants. Brain MRIs of individuals harboring such variants were scored according to Standards for Reporting Vascular Changes on Neuroimaging criteria, and clinical information was extracted with ICD-10 codes. Clinical and neuroimaging data were compared to age- and sex-matched UK Biobank controls and clinically diagnosed patients from the Dutch cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) registry. Results We identified 108 individuals harboring a cysteine-altering NOTCH3 variant (2.2 of 1,000), of whom 75% have a variant that has previously been reported in CADASIL pedigrees. Almost all variants were located in 1 of the NOTCH3 protein epidermal growth factor–like repeat domains 7 to 34. White matter hyperintensity lesion load was higher in individuals with NOTCH3 variants than in controls (p = 0.006) but lower than in patients with CADASIL with the same variants (p < 0.001). Almost half of the 24 individuals with brain MRI had a Fazekas score of 0 or 1 up to age 70 years. There was no increased risk of stroke. Conclusions Although community-dwelling individuals harboring a cysteine-altering NOTCH3 variant have a higher small vessel disease MRI burden than controls, almost half have no MRI abnormalities up to age 70 years. This shows that NOTCH3 cysteine altering variants are associated with an extremely broad phenotypic spectrum, ranging from CADASIL to nonpenetrance.Item Developing and applying potentially scalable recruitment strategies to accelerate ADRD research participation of Black adults(Wiley, 2025) Richards, Ralph; Richards, Mollie; Musema, Jane; Tackett, Andrew; Van Heiden, Sarah; Polsinelli, Angelina; Gao, Sujuan; Brown, Steven A.; Unverzagt, Frederick W.; Risacher, Shannon; Adeoye-Olatunde, Omolola; Campbell, Christopher; Shaw, Pamella; Saykin, Andrew; Wang, Sophia; Neurology, School of MedicineMore than 2 million older Americans from underrepresented racial and ethnic minority groups (URGs) have early-stage Alzheimer's disease and related dementias (ADRD). There are very few scalable recruitment strategies, particularly for Black older adults, to accelerate participation in ADRD research. The Indiana Alzheimer's Disease Research Center (IADRC) and its Community Advisory Board developed and implemented the innovative RAAISE-D Framework. This Framework informed the creation of community-first recruitment strategies designed to accelerate participation of Black older adults in ADRD research. Preliminary outcomes from its implementation included the doubling of Black adult enrollment (46, 13.4% to 101, 26.9%) from April 2020 to April 2024. Black adults were more likely to have normal cognition, be female, and ≤ 12 years of education than non-Hispanic White adults. The RAAISE-D Framework identified key concepts for URG focused recruitment strategies which successfully accelerated enrollment of Black adults in ADRD research and could be generalized to other URGs. HIGHLIGHTS: RAAISE-D Framework provides adaptable URG recruitment strategies. IADRC CAB-researcher partnership was the foundation of community-first methodology. RAAISE-D Framework doubled the Black enrollment in the IADRC in 4 years.Item Epigenome-wide meta-analysis of blood DNA methylation and its association with subcortical volumes: findings from the ENIGMA Epigenetics Working Group(Springer Nature, 2021) Jia, Tianye; Chu, Congying; Liu, Yun; Van Dongen, Jenny; Papastergios, Evangelos; Armstrong, Nicola J.; Bastin, Mark E.; Carrillo-Roa, Tania; den Braber, Anouk; Harris, Mathew; Jansen, Rick; Liu, Jingyu; Luciano, Michelle; Ori, Anil P.S.; Santiañez, Roberto Roiz; Ruggeri, Barbara; Sarkisyan, Daniil; Shin, Jean; Sungeun, Kim; Tordesillas Gutiérrez, Diana; van't Ent, Dennis; Ames, David; Artiges, Eric; Bakalkin, Georgy; Banaschewski, Tobias; Bokde, Arun L.W.; Brodaty, Henry; Bromberg, Uli; Brouwer, Rachel; Büchel, Christian; Burke Quinlan, Erin; Cahn, Wiepke; de Zubicaray, Greig I.; Ehrlich, Stefan; Ekström, Tomas J.; Flor, Herta; Fröhner, Juliane H.; Frouin, Vincent; Garavan, Hugh; Gowland, Penny; Heinz, Andreas; Hoare, Jacqueline; Ittermann, Bernd; Jahanshad, Neda; Jiang, Jiyang; Kwok, John B.; Martin, Nicholas G.; Martinot, Jean-Luc; Mather, Karen A.; McMahon, Katie L.; McRae, Allan F.; Nees, Frauke; Orfanos, Dimitri Papadopoulos; Paus, Tomáš; Poustka, Luise; Sämann, Philipp G.; Schofield, Peter R.; Smolka, Michael N.; Stein, Dan J.; Strike, Lachlan T.; Teeuw, Jalmar; Thalamuthu, Anbupalam; Trollor, Julian; Walter, Henrik; Wardlaw, Joanna M.; Wen, Wei; Whelan, Robert; Apostolova, Liana G.; Binder, Elisabeth B.; Boomsma, Dorret I.; Calhoun, Vince; Crespo-Facorro, Benedicto; Deary, Ian J.; Hulshoff Pol, Hilleke; Ophoff, Roel A.; Pausova, Zdenka; Sachdev, Perminder S.; Saykin, Andrew; Wright, Margaret J.; Thompson, Paul M.; Schumann, Gunter; Desrivières, Sylvane; Radiology and Imaging Sciences, School of MedicineDNA methylation, which is modulated by both genetic factors and environmental exposures, may offer a unique opportunity to discover novel biomarkers of disease-related brain phenotypes, even when measured in other tissues than brain, such as blood. A few studies of small sample sizes have revealed associations between blood DNA methylation and neuropsychopathology, however, large-scale epigenome-wide association studies (EWAS) are needed to investigate the utility of DNA methylation profiling as a peripheral marker for the brain. Here, in an analysis of eleven international cohorts, totalling 3337 individuals, we report epigenome-wide meta-analyses of blood DNA methylation with volumes of the hippocampus, thalamus and nucleus accumbens (NAcc)—three subcortical regions selected for their associations with disease and heritability and volumetric variability. Analyses of individual CpGs revealed genome-wide significant associations with hippocampal volume at two loci. No significant associations were found for analyses of thalamus and nucleus accumbens volumes. Cluster-based analyses revealed additional differentially methylated regions (DMRs) associated with hippocampal volume. DNA methylation at these loci affected expression of proximal genes involved in learning and memory, stem cell maintenance and differentiation, fatty acid metabolism and type-2 diabetes. These DNA methylation marks, their interaction with genetic variants and their impact on gene expression offer new insights into the relationship between epigenetic variation and brain structure and may provide the basis for biomarker discovery in neurodegeneration and neuropsychiatric conditions.Item Exploring the Nexus of Alzheimer’s Disease and Related Dementias with Cancer and Cancer Therapies(Elsevier, 2017-03) Snyder, Heather M.; Ahles, Timothy; Calderwood, Stuart; Carrillo, Maria C.; Chen, Honglei; Chang, Chung-Chou; Craft, Suzanne; De Jager, Philip; Driver, Jane A.; Fillet, Howard; Knopman, David; Lotze, Michael; Tierney, Mary C.; Petanceska, Suzana; Saykin, Andrew; Seshadri, Sudha; Shineman, Diana; Ganguli, Mary; Radiology and Imaging Sciences, School of MedicineRecent population studies suggest an intriguing inverse relationship between several types of cancer and neurodegenerative diseases, including Alzheimer’s disease. Understanding the intersection of the underlying biology for these two distinct families of diseases with one another may offer novel approaches to identify new therapeutic approaches and possible opportunities to repurpose existing drug candidates. The Alzheimer’s Association and the Alzheimer’s Drug Discovery Foundation convened a one day workshop to delve into this discussion. Workshop participants outlined research focus areas, potential collaborations and partnerships for future action.Item Genetic variants for Alzheimer’s disease and comorbid conditions(Sage, 2024) Pan, Minmin; Lai, Dongbing; Unverzagt, Frederick; Apostolova, Liana; Hendrie, Hugh C.; Saykin, Andrew; Foroud, Tatiana; Gao, Sujuan; Biostatistics and Health Data Science, Richard M. Fairbanks School of Public HealthBackground: Alzheimer's disease and related dementias (ADRD) frequently co-occur with comorbidities such as diabetes and cardiovascular diseases in elderly populations. Objective: Utilize a life-course approach to identify genetic variants that are associated with the co-occurrence of ADRD and another comorbid condition. Methods: Research data from African American participants of the Indianapolis-Ibadan Dementia Project (IIDP) linked with electronic medical record (EMR) data and genome-wide association study (GWAS) data were utilized. The age of onset for ADRD was obtained from longitudinal follow-up of the IIDP study. Age of onset for comorbid conditions was obtained from EMR. The analysis included 1177 African Americans, among whom 174 were diagnosed with ADRD. A semi-parametric marginal bivariate survival model was used to examine the influence of single nucleotide polymorphisms (SNPs) on dual time-to-event outcomes while adjusting for sex, years of education, and the first principal component of GWAS data. Results: Targeted analysis of 20 SNPs that were reported to be associated with ADRD revealed that six were significantly associated with dual-disease outcomes, specifically congestive heart failure and cancer. In addition, eight novel SNPs were identified for associations with both ADRD and a comorbid condition. Conclusions: Using a bivariate survival model approach, we identified genetic variants associated not only with ADRD, but also with comorbid conditions. Our utilization of dual-disease models represents a novel analytic strategy for uncovering shared genetic variants for multiple disease phenotypes.Item The Impact of Amyloid Burden and APOE on Rates of Cognitive Impairment in Late Life Depression(IOS Press, 2021) Rhodes, Emma; Insel, Philip S.; Butters, Meryl A.; Morin, Ruth; Bickford, David; Tosun, Duygu; Gessert, Devon; Rosen, Howie J.; Aisen, Paul; Raman, Rema; Landau, Susan; Saykin, Andrew; Toga, Arthur; Jack, Clifford R.; Weiner, Michael W.; Nelson, Craig; Mackin, R. Scott; Alzheimer’s Disease Neuroimaging Initiative; ADNI Depression Project; Radiology and Imaging Sciences, School of MedicineBackground: Cognitive impairment (CI) is a key feature of late life depression (LLD), but the contribution of underlying neurodegenerative pathology remains unclear. Objective: To evaluate cognitive dysfunction in LLD relative to a sample of nondepressed (ND) older adults with matched levels of memory impairment and amyloid-β (Aβ) burden. Methods: Participants included 120 LLD and 240 ND older adults matched on age, education, sex, Mini-Mental State Exam, mild cognitive impairment diagnosis, and PET Aβ burden. Results: LLD showed higher rates of impairment relative to ND with 54.6% of the LLD sample demonstrating impairment in at least one cognitive domain compared to 42.9% of controls (H = 7.13, p = 0.008). LLD had poorer performance and higher rates of impairment on Rey Auditory Verbal Learning Test learning and memory compared to controls. In the overall sample, Aβ positivity was associated with worse performance on Logical Memory I (p = 0.044), Logical Memory II (p = 0.011), and Trail Making Test -B (p = 0.032), and APOEɛ4 genotype was associated with worse performance on Logical Memory I (p = 0.022); these relationships did not differ between LLD and ND. Conclusion: LLD showed higher rates of CI driven by focal deficits in verbal learning and memory. Alzheimer's disease (AD) biomarkers were associated with worse performance on timed set-shifting and story learning and memory, and these relationships were not impacted by depression status. These findings suggest that AD may account for a portion of previously reported multi-domain CI in LLD and highlight the potential for AD to confound studies of cognition in LLD.