GLORIA

GEOMAR Library Ocean Research Information Access

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    In: Nature Genetics, Springer Science and Business Media LLC, Vol. 54, No. 4 ( 2022-04), p. 412-436
    Abstract: Characterization of the genetic landscape of Alzheimer’s disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/‘proxy’ AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele.
    Type of Medium: Online Resource
    ISSN: 1061-4036 , 1546-1718
    RVK:
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 1494946-5
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    In: Alzheimer's & Dementia, Wiley, Vol. 17, No. S4 ( 2021-12)
    Abstract: Mitochondria are the main energy source for normal neuronal functions. Mitochondrial DNA (mtDNA) copy number (CN), a measure of mtDNA levels in the cell, correlates with cellular energy generating capacity and metabolic status. Previous studies have observed a significant decrease of circulating cell‐free mtDNA content in the cerebrospinal fluid of patients with Alzheimer's disease (AD). However, it is unknown whether mtDNA CN circulating in the blood is related to AD endophenotypes. We aimed to investigate the cross‐sectional association of mtDNA CN with MRI markers of abnormal brain aging and cognitive function. Method We included dementia‐free, multiethnic participants from seven population‐based cohorts with whole‐genome sequencing as part of the Trans‐Omics for Precision Medicine (TOPMed) program. The average mtDNA CN in whole blood was estimated as twice the ratio of the average coverage of mtDNA to the average coverage of the nuclear DNA using fastMitoCalc from mitoAnalyzer. Brain MRI markers included total brain volume, hippocampal volume, and white matter hyperintensities. General cognitive function was derived from at least three distinct cognitive domains using principal component analysis. We related mtDNA CN to AD endophenotypes assessed within 5 years of blood draw per cohort and further performed random‐effects or sample size‐weighted meta‐analyses. Models were adjusted for demographics and vascular risk factors. Result Higher mtDNA CN was significantly associated with better general cognitive function (P‐values 〈 0.05) in four cohorts after adjusting for age, sex, batch effect, self‐reported race/ethnicity, the time between blood draw and MRI/Cognitive evaluation, cohort‐specific variables, and education (Figure 1). Meta‐analysis across all cohorts confirmed and strengthened the significant association between mtDNA CN and general cognitive function (n=11,021, Beta=0.046, SE=0.01, P‐value=0.0002). Additional adjustment for diabetes, hypertension, hyperlipidemia, and obesity led to similar results (Beta=0.043, SE=0.01, P‐value=0.002). We observed no significant associations between mtDNA CN and brain MRI markers. Conclusion This study suggests that higher mtDNA CN is cross‐sectionally associated with better general cognitive function in a large sample from diverse communities across the US, providing novel findings that support the role of mtDNA in healthy brain aging. Additional analyses are underway to relate mtDNA CN to AD endophenotypes prospectively and to incident dementia.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2201940-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    In: Neurology, Ovid Technologies (Wolters Kluwer Health), Vol. 100, No. 18 ( 2023-05-2), p. e1930-e1943
    Abstract: Previous studies suggest that lower mitochondrial DNA (mtDNA) copy number (CN) is associated with neurodegenerative diseases. However, whether mtDNA CN in whole blood is related to endophenotypes of Alzheimer disease (AD) and AD-related dementia (AD/ADRD) needs further investigation. We assessed the association of mtDNA CN with cognitive function and MRI measures in community-based samples of middle-aged to older adults. Methods We included dementia-free participants from 9 diverse community-based cohorts with whole-genome sequencing in the Trans-Omics for Precision Medicine (TOPMed) program. Circulating mtDNA CN was estimated as twice the ratio of the average coverage of mtDNA to nuclear DNA. Brain MRI markers included total brain, hippocampal, and white matter hyperintensity volumes. General cognitive function was derived from distinct cognitive domains. We performed cohort-specific association analyses of mtDNA CN with AD/ADRD endophenotypes assessed within ±5 years (i.e., cross-sectional analyses) or 5–20 years after blood draw (i.e., prospective analyses) adjusting for potential confounders. We further explored associations stratified by sex and age ( 〈 60 vs ≥60 years). Fixed-effects or sample size-weighted meta-analyses were performed to combine results. Finally, we performed mendelian randomization (MR) analyses to assess causality. Results We included up to 19,152 participants (mean age 59 years, 57% women). Higher mtDNA CN was cross-sectionally associated with better general cognitive function (β = 0.04; 95% CI 0.02–0.06) independent of age, sex, batch effects, race/ethnicity, time between blood draw and cognitive evaluation, cohort-specific variables, and education. Additional adjustment for blood cell counts or cardiometabolic traits led to slightly attenuated results. We observed similar significant associations with cognition in prospective analyses, although of reduced magnitude. We found no significant associations between mtDNA CN and brain MRI measures in meta-analyses. MR analyses did not reveal a causal relation between mtDNA CN in blood and cognition. Discussion Higher mtDNA CN in blood is associated with better current and future general cognitive function in large and diverse communities across the United States. Although MR analyses did not support a causal role, additional research is needed to assess causality. Circulating mtDNA CN could serve nevertheless as a biomarker of current and future cognitive function in the community.
    Type of Medium: Online Resource
    ISSN: 0028-3878 , 1526-632X
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2023
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    In: Communications Biology, Springer Science and Business Media LLC, Vol. 5, No. 1 ( 2022-04-08)
    Abstract: Circulating total-tau levels can be used as an endophenotype to identify genetic risk factors for tauopathies and related neurological disorders. Here, we confirmed and better characterized the association of the 17q21 MAPT locus with circulating total-tau in 14,721 European participants and identified three novel loci in 953 African American participants (4q31, 5p13, and 6q25) at P   〈  5 × 10 −8 . We additionally detected 14 novel loci at P   〈  5 × 10 −7 , specific to either Europeans or African Americans. Using whole-exome sequence data in 2,279 European participants, we identified ten genes associated with circulating total-tau when aggregating rare variants. Our genetic study sheds light on genes reported to be associated with neurological diseases including stroke, Alzheimer’s, and Parkinson’s ( F 5, MAP1B , and BCAS3 ), with Alzheimer’s pathological hallmarks ( ADAMTS12 , IL15 , and FHIT ), or with an important function in the brain ( PARD3 , ELFN2 , UBASH3B , SLIT3 , and NSD3 ), and suggests that the genetic architecture of circulating total-tau may differ according to ancestry.
    Type of Medium: Online Resource
    ISSN: 2399-3642
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2919698-X
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    In: Journal of Alzheimer's Disease, IOS Press, Vol. 90, No. 3 ( 2022-11-22), p. 1073-1083
    Abstract: Background: Previous studies suggest poor pulmonary function is associated with increased burden of cerebral white matter hyperintensities and brain atrophy among elderly individuals, but the results are inconsistent. Objective: To study the cross-sectional associations of pulmonary function with structural brain variables. Methods: Data from six large community-based samples (N = 11,091) were analyzed. Spirometric measurements were standardized with respect to age, sex, height, and ethnicity using reference equations of the Global Lung Function Initiative. Associations of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and their ratio FEV1/FVC with brain volume, gray matter volume, hippocampal volume, and volume of white matter hyperintensities were investigated using multivariable linear regressions for each study separately and then combined using random-effect meta-analyses. Results: FEV1 and FVC were positively associated with brain volume, gray matter volume, and hippocampal volume, and negatively associated with white matter hyperintensities volume after multiple testing correction, with little heterogeneity present between the studies. For instance, an increase of FVC by one unit was associated with 3.5 ml higher brain volume (95% CI: [2.2, 4.9]). In contrast, results for FEV1/FVC were more heterogeneous across studies, with significant positive associations with brain volume, gray matter volume, and hippocampal volume, but not white matter hyperintensities volume. Associations of brain variables with both FEV1 and FVC were consistently stronger than with FEV1/FVC, specifically with brain volume and white matter hyperintensities volume. Conclusion: In cross-sectional analyses, worse pulmonary function is associated with smaller brain volumes and higher white matter hyperintensities burden.
    Type of Medium: Online Resource
    ISSN: 1387-2877 , 1875-8908
    Language: Unknown
    Publisher: IOS Press
    Publication Date: 2022
    detail.hit.zdb_id: 2070772-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S4 ( 2022-12)
    Abstract: Insulin resistance (IR) is a major risk factor for Alzheimer’s disease (AD) and is primarily driven by obesity, another AD risk factor. The mechanism by which IR predisposes to AD is unknown. Epigenetic studies may help identify molecular signatures of IR associated with AD, thus contributing to an improved understanding of the biological and regulatory mechanisms of IR in AD. Method We conducted an epigenome‐wide association study of IR, quantified using the homeostasis model assessment of IR, in 3,167 Framingham Heart Study (FHS) participants without diabetes. We selected epigenetic markers (outcome) associated with IR at the genome‐wide level ( P 〈 10 ‐7 : 0.05/450,000) and evaluated their association with AD, vascular dementia, dementia, and brain volumes (hippocampal, total brain‐TBV, intracranial‐ICV, and lateral ventricular) in up to 3,040 FHS participants. We defined significant associations using P 〈 0.002 (0.05/3/7). All analyses were performed using blood DNA methylation measured using the Illumina HumanMethylation450 BeadChip and linear mixed‐effects models adjusted for age, sex, and batch, while allowing for heterogeneous variance across batches and accounting for familial relatedness. Models including IR or brain volume as a covariate were additionally adjusted for body mass index or ICV respectively. Result We confirmed the association of blood DNA methylation with IR at three loci (1p32:cg17901584‐ DHCR24 , 11q13:cg17058475‐ CPT1A , and 21q22:cg06500161‐ ABCG1 ). Blood DNA methylation at cg17058475‐ CPT1A was significantly associated with TBV ( P =0.0007). The carnitine palmitoyl transferase (CPT) system, crucial for the mitochondrial beta‐oxidation of long‐chain fatty acids, is involved in metabolic syndrome, type 2 diabetes, cardiovascular and neurological diseases including AD. Blood DNA methylation levels at cg17901584‐ DHCR24 and cg06500161‐ ABCG1 were nominally associated with AD ( P =0.03) or vascular dementia ( P =0.04) respectively. Both DHCR24 and ABCG1 are involved in cholesterol synthesis or transport. Reduced expression of DHCR24 occurs in AD patient’s temporal cortex while CSF capacity to promote cell cholesterol efflux via ABCG1 is specifically impaired in AD and this impairment correlates with the main AD neurobiochemical markers. Conclusion Our methylation analysis has shed light on genes potentially implicated in both IR and AD. Future work includes association analyses using brain omics from the AD Knowledge Portal.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2201940-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S6 ( 2022-12)
    Abstract: Neurofilament light chain (NfL) is a broad marker of neuroaxonal injury that is elevated in the CSF in those with vascular cognitive impairment and dementia (VCID). Blood and CSF levels highly correlate, making it an attractive peripheral marker for VCID pathology. As part of the MarkVCID consortium, we sought to evaluate the instrumental validity of plasma NfL using the Quanterix Simoa platform and assess its validity for risk stratification in clinical trials of VCID. Method Plasma NfL was measured using HD‐X and HD‐1 Simoa instruments. For instrumental validation, we used samples from the MarkVCID consortium to evaluate intra‐ and inter‐plate reliability, test‐retest repeatability, and inter‐site reproducibility. We used linear regression models to assess the association of NfL with general cognitive function (GCF) as the primary outcome. In secondary analyses we assessed associations with white matter hyperintensities (WMH), an established small vessel disease marker. Models were adjusted for potential confounders. The clinical validation included established cohorts from the CHARGE consortium (i.e., CARDIA, ARIC, FHS, AGES; n=4,772), the UKY ADRC (n=350), and the UCD ADRC (n=196). Additional analyses are underway in MarkVCID sites. Result We found low coefficients of variation (average CV 〈 12%), high inter‐site reproducibility (overall ICC = 0.93) and high repeatability in blood samples drawn within 30 days (ICC=0.968). There was high consistency across Quanterix instruments (HD‐X and HD‐1; R 2 ≥0.98) and kits (N4PA and single molecule NfL; ICC≥0.81). We observed consistent significant associations between higher NfL concentrations and worse GCF in CHARGE cohorts (meta‐analysis β=‐0.11; [95% CI ‐0.06; ‐0.17]), the UKY ADRC (β=‐0.16; [95% CI ‐0.27; ‐0.05] ) and the UCD ADRC (UCD: β=‐0.28; [95% CI ‐0.48; ‐0.08). Secondary analyses revealed significant associations between elevated NfL concentrations and higher WMH burden in CHARGE cohorts and the UCD ADRC (P 〈 0.01). Conclusion Our results suggest plasma NfL can be reliably measured using the Quanterix platform, making this marker ideal for multi‐site clinical trials. We observed consistent associations for plasma NfL concentrations with cognition and WMH across independent samples, providing evidence that plasma NfL can be a useful biomarker for stratification in VCID trials.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2201940-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    In: Journal of Alzheimer's Disease, IOS Press, ( 2023-10-09), p. 1-11
    Abstract: Background: White matter hyperintensities (WMH) that occur in the setting of vascular cognitive impairment and dementia (VCID) may be dynamic increasing or decreasing volumes or stable over time. Quantifying such changes may prove useful as a biomarker for clinical trials designed to address vascular cognitive-impairment and dementia and Alzheimer’s Disease. Objective: Conducting multi-site cross-site inter-rater and test-retest reliability of the MarkVCID white matter hyperintensity growth and regression protocol. Methods: The NINDS-supported MarkVCID Consortium evaluated a neuroimaging biomarker developed to track WMH change. Test-retest and cross-site inter-rater reliability of the protocol were assessed. Cognitive test scores were analyzed in relation to WMH changes to explore its construct validity. Results: ICC values for test-retest reliability of WMH growth and regression were 0.969 and 0.937 respectively, while for cross-site inter-rater ICC values for WMH growth and regression were 0.995 and 0.990 respectively. Word list long-delay free-recall was negatively associated with WMH growth (p 〈 0.028) but was not associated with WMH regression. Conclusions: The present data demonstrate robust ICC validity of a WMH growth/regression protocol over a one-year period as measured by cross-site inter-rater and test-retest reliability. These data suggest that this approach may serve an important role in clinical trials of disease-modifying agents for VCID that may preferentially affect WMH growth, stability, or regression.
    Type of Medium: Online Resource
    ISSN: 1387-2877 , 1875-8908
    Language: Unknown
    Publisher: IOS Press
    Publication Date: 2023
    detail.hit.zdb_id: 2070772-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S11 ( 2022-12)
    Abstract: Genome‐wide association studies (GWAS) of brain volumes have identified common genetic variants with modest effect sizes that lie mainly in non‐coding regions. We sought to identify low frequency and rare variants influencing brain volumes by performing association analyses using whole‐genome sequence data from the Trans‐Omics for Precision Medicine (TOPMed) Program. Method We analyzed up to 7,607 participants (57% women; 62% European ancestry, 21% African‐Americans, 15% Hispanic/Latino, 2% Chinese‐American), mean age of 60.5 (16.2), from eight TOPMed population‐ or family‐based studies (FHS, GENESTAR, CHS, GENOA, ARIC, CARDIA, MESA, and SAFS). We excluded participants with dementia, stroke, presence of large brain infarcts, tumor or low‐quality scans. We tested the association of hippocampal (HV), total brain (TBV), lateral ventricular (LVV) and intracranial (ICV) volumes to individual genetic variants with minor allele counts ≥ 15 using mixed‐effect linear regression models adjusted for age, age 2 , sex, study and the first 10 principal components. Models for HV, TBV and log(LVV) were adjusted for ICV. We accounted for relatedness using an empirical kinship matrix and trait variance variability by using a random effect for study. Result We detected one novel region with low frequency variants associated with HV (13q14, P = 5.8×10 −9 ). The top 13q14 variant for HV (rs115674829) minor allele frequency (MAF) was 2% in our pooled sample but was more common in the pan‐African 1000 Genomes population (MAF = 14%). This variant lies in LINC00598 at 237kb from FOXO1 , a member of the forkhead family of transcription factors that has been linked to Alzheimer’s Disease. Additionally, we detected new suggestive associations (P≤10 −7 ) for TBV (16p11) and LVV (1q25, 2q22, 3q13, 5q14, and 10q23), including common variants. Finally, we confirmed the association of common variants in GWAS loci for all traits. Conclusion Our whole genome sequence analyses revealed intriguing new loci of low‐frequency and common variants, and replicated loci previously associated with brain volumes. Future work will include ancestry‐specific and conditional analyses, as well as gene‐based and scan tests. Supported by: AG058589, AG052409, AG054076, NO1‐HC‐25195, HHSN268201500001I and 75N92019D00031, R01HL131136, P30 AG066546, and K99AG066849.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2201940-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 10
    In: Annals of Clinical and Translational Neurology, Wiley, Vol. 9, No. 10 ( 2022-10), p. 1574-1585
    Abstract: Expression of glial fibrillary acidic protein (GFAP), a marker of reactive astrocytosis, colocalizes with neuropathology in the brain. Blood levels of GFAP have been associated with cognitive decline and dementia status. However, further examinations at a population‐based level are necessary to broaden generalizability to community settings. Methods Circulating GFAP levels were assayed using a Simoa HD‐1 analyzer in 4338 adults without prevalent dementia from four longitudinal community‐based cohort studies. The associations between GFAP levels with general cognition, total brain volume, and hippocampal volume were evaluated with separate linear regression models in each cohort with adjustment for age, sex, education, race, diabetes, systolic blood pressure, antihypertensive medication, body mass index, apolipoprotein E ε4 status, site, and time between GFAP blood draw and the outcome. Associations with incident all‐cause and Alzheimer's disease dementia were evaluated with adjusted Cox proportional hazard models. Meta‐analysis was performed on the estimates derived from each cohort using random‐effects models. Results Meta‐analyses indicated that higher circulating GFAP associated with lower general cognition ( ß  = −0.09, [95% confidence interval [CI]: −0.15 to −0.03] , p  = 0.005), but not with total brain or hippocampal volume ( p   〉  0.05). However, each standard deviation unit increase in log‐transformed GFAP levels was significantly associated with a 2.5‐fold higher risk of incident all‐cause dementia (Hazard Ratio [HR]: 2.47 (95% CI: 1.52–4.01)) and Alzheimer's disease dementia (HR: 2.54 [95% CI: 1.42–4.53] ) over up to 15‐years of follow‐up. Interpretation Results support the potential role of circulating GFAP levels for aiding dementia risk prediction and improving clinical trial stratification in community settings.
    Type of Medium: Online Resource
    ISSN: 2328-9503 , 2328-9503
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2740696-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...