%0 Journal Article %J J Alzheimers Dis %D 2023 %T Proteome Network Analysis Identifies Potential Biomarkers for Brain Aging. %A Short, Meghan I %A Fohner, Alison E %A Skjellegrind, Håvard K %A Beiser, Alexa %A Gonzales, Mitzi M %A Satizabal, Claudia L %A Austin, Thomas R %A Longstreth, W T %A Bis, Joshua C %A Lopez, Oscar %A Hveem, Kristian %A Selbæk, Geir %A Larson, Martin G %A Yang, Qiong %A Aparicio, Hugo J %A McGrath, Emer R %A Gerszten, Robert E %A DeCarli, Charles S %A Psaty, Bruce M %A Vasan, Ramachandran S %A Zare, Habil %A Seshadri, Sudha %X

BACKGROUND: Alzheimer's disease and related dementias (ADRD) involve biological processes that begin years to decades before onset of clinical symptoms. The plasma proteome can offer insight into brain aging and risk of incident dementia among cognitively healthy adults.

OBJECTIVE: To identify biomarkers and biological pathways associated with neuroimaging measures and incident dementia in two large community-based cohorts by applying a correlation-based network analysis to the plasma proteome.

METHODS: Weighted co-expression network analysis of 1,305 plasma proteins identified four modules of co-expressed proteins, which were related to MRI brain volumes and risk of incident dementia over a median 20-year follow-up in Framingham Heart Study (FHS) Offspring cohort participants (n = 1,861). Analyses were replicated in the Cardiovascular Health Study (CHS) (n = 2,117, mean 6-year follow-up).

RESULTS: Two proteomic modules, one related to protein clearance and synaptic maintenance (M2) and a second to inflammation (M4), were associated with total brain volume in FHS (M2: p = 0.014; M4: p = 4.2×10-5). These modules were not significantly associated with hippocampal volume, white matter hyperintensities, or incident all-cause or AD dementia. Associations with TCBV did not replicate in CHS, an older cohort with a greater burden of comorbidities.

CONCLUSIONS: Proteome networks implicate an early role for biological pathways involving inflammation and synaptic function in preclinical brain atrophy, with implications for clinical dementia.

%B J Alzheimers Dis %V 96 %P 1767-1780 %8 2023 Dec 05 %G eng %N 4 %R 10.3233/JAD-230145 %0 Journal Article %J J Alzheimers Dis %D 2022 %T Associations of Pulmonary Function with MRI Brain Volumes: A Coordinated Multi-Study Analysis. %A Frenzel, Stefan %A Bis, Josh C %A Gudmundsson, Elias F %A O'Donnell, Adrienne %A Simino, Jeannette %A Yaqub, Amber %A Bartz, Traci M %A Brusselle, Guy G O %A Bülow, Robin %A DeCarli, Charles S %A Ewert, Ralf %A Gharib, Sina A %A Ghosh, Saptaparni %A Gireud-Goss, Monica %A Gottesman, Rebecca F %A Ikram, M Arfan %A Knopman, David S %A Launer, Lenore J %A London, Stephanie J %A Longstreth, W T %A Lopez, Oscar L %A Melo van Lent, Debora %A O'Connor, George %A Satizabal, Claudia L %A Shrestha, Srishti %A Sigurdsson, Sigurdur %A Stubbe, Beate %A Talluri, Rajesh %A Vasan, Ramachandran S %A Vernooij, Meike W %A Völzke, Henry %A Wiggins, Kerri L %A Yu, Bing %A Beiser, Alexa S %A Gudnason, Vilmundur %A Mosley, Thomas %A Psaty, Bruce M %A Wolters, Frank J %A Grabe, Hans J %A Seshadri, Sudha %X

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 s (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.

%B J Alzheimers Dis %V 90 %P 1073-1083 %8 2022 Nov 22 %G eng %N 3 %R 10.3233/JAD-220667 %0 Journal Article %J J Alzheimers Dis %D 2022 %T Insulin-Like Growth Factor, Inflammation, and MRI Markers of Alzheimer's Disease in Predominantly Middle-Aged Adults. %A Wittfeld, Katharina %A Raman, Mekala R %A Conner, Sarah C %A Aslam, Asra %A Teumer, Alexander %A Nauck, Matthias %A Hosten, Norbert %A Habes, Mohamad %A DeCarli, Charles %A Vasan, Ramachandran S %A Beiser, Alexa S %A Himali, Jayandra J %A Seshadri, Sudha %A Grabe, Hans J %A Satizabal, Claudia L %X

BACKGROUND: Insulin-like growth factor 1 (IGF-1) signaling has been implicated in Alzheimer's disease pathogenesis, and further evidence suggests inflammation can be a moderator of this association. However, most research to date has been conducted on older adults.

OBJECTIVE: To investigate the association of serum IGF-1 and IGF binding protein 3 (IGFBP-3) concentrations with MRI markers of Alzheimer's disease in predominantly middle-aged adults, and further assess moderation by chronic inflammation.

METHODS: We included participants from the Framingham Heart Study (n = 1,852, mean age 46±8, 46% men) and the Study of Health in Pomerania (n = 674, mean age 50±13, 42% men) with available serum IGF-1, IFGBP-3, as well as brain MRI. IGF-1 and IFGBP-3 were related to MRI outcomes (i.e., total brain, cortical gray matter, white matter, white matter hyperintensities (WMH), and hippocampal volumes) using multivariable regression models adjusting for potential confounders. Subgroup analyses by C-reactive protein (CRP) concentrations were also performed. Cohort-specific summary statistics were meta-analyzed using random-effects models and corrected for multiple comparisons.

RESULTS: Meta-analysis results revealed that higher IGF-1 concentrations were associated with lower WMH (estimate [β] [95% CI], -0.05 [-0.09, -0.02], p = 0.006) and larger hippocampal volumes (0.07 [0.02, 0.12], p = 0.01), independent of vascular risk factors. These associations occurred predominantly in individuals with CRP concentrations < 75th percentile. We did not observe associations between IGFBP-3 and MRI outcomes.

CONCLUSION: Our findings suggest that IGF-1-related signaling may be implicated in brain health as early as midlife.

%B J Alzheimers Dis %V 88 %P 311-32 %8 2022 Jun 28 %G eng %N 1 %R 10.3233/JAD-220356 %0 Journal Article %J J Alzheimers Dis %D 2021 %T Accelerometer-Measured, Habitual Physical Activity and Circulating Brain-Derived Neurotrophic Factor: A Cross-Sectional Study. %A Spartano, Nicole L %A Himali, Jayandra J %A Trinquart, Ludovic %A Yang, Qiong %A Weinstein, Galit %A Satizabal, Claudia L %A Dukes, Kimberly A %A Beiser, Alexa S %A Murabito, Joanne M %A Vasan, Ramachandran S %A Seshadri, Sudha %X

BACKGROUND: One of the mechanisms suggested to link physical activity (PA) to favorable brain health is through stimulation of neural growth factors such as brain-derived neurotrophic factor (BDNF). Acute bouts of PA stimulate circulating BDNF levels.

OBJECTIVE: In this investigation, we assessed whether habitual, accelerometer-measured PA levels were related to circulating BDNF levels in a middle-aged cohort.

METHODS: In the Framingham Heart Study Third Generation cohort, 1,769 participants provided reliable accelerometry data and were not missing BDNF measurement and platelet counts. In a cross-sectional analysis, using multivariable regression, we related PA measures to serum BDNF levels, adjusting for age, sex, smoking status, platelet count, depression status, and accelerometer wear time.

RESULTS: Our study participants (mean age 47±9 years, 50.8% women) spent an average of 22.3 mins/day moderate-to-vigorous (MV)PA. Most PA variables (steps, MVPA, light activity, and sedentary time) were not related to BDNF levels (p > 0.05). We observed a non-linear trend, where 15-50 mins/week vigorous activity was associated with lower BDNF compared to those with 0 min vigorous activity (β= -0.049±0.024, p = 0.05), but with no significant associations at lower or higher vigorous activity levels. In smokers, MVPA was also associated with lower BDNF levels (β= -0.216±0.079, p = 0.01).

CONCLUSION: Our study reveals that circulating BDNF is not chronically elevated in individuals with higher levels of habitual PA in middle-aged adults from the community and may even be chronically suppressed with higher PA in subgroups, including current smokers. These results do not contradict previous studies demonstrating that circulating BDNF rises acutely after PA.

%B J Alzheimers Dis %V 85 %P 805-814 %8 2022 Jan 18 %G eng %N 2 %R 10.3233/JAD-215109 %0 Journal Article %J J Alzheimers Dis %D 2021 %T Plasma EFEMP1 Is Associated with Brain Aging and Dementia: The Framingham Heart Study. %A McGrath, Emer R %A Himali, Jayandra J %A Levy, Daniel %A Yang, Qiong %A DeCarli, Charles S %A Courchesne, Paul %A Satizabal, Claudia L %A Finney, Rebecca %A Vasan, Ramachandran S %A Beiser, Alexa S %A Seshadri, Sudha %X

BACKGROUND: Epidermal growth factor containing fibulin extracellular matrix protein-1 (EFEMP1) has been associated with increased white matter hyperintensities (WMH) burden and disorders of premature aging and may have a shared pathophysiological role in the development of WMH and dementia.

OBJECTIVE: To determine the association between plasma EFEMP1 levels and MRI markers of vascular brain injury and incident all-cause and Alzheimer's disease (AD) dementia.

METHODS: We measured plasma EFEMP1 levels in 1597 [53% women, mean age 68.7 (SD 5.7) years] dementia-free Framingham Offspring cohort participants between 1998-2001 and subsequently followed them for incident dementia. Secondary outcomes included stroke, structural MRI brain measures and neurocognitive test performance.

RESULTS: During a median 11.8 [Q1, Q3 : 7.1, 13.3] year follow-up, 131 participants developed dementia. The highest quintile of plasma EFEMP1, compared to the bottom four quintiles, was associated with an increased risk of time to incident all-cause dementia (HR 1.77, 95% CI 1.18-2.64) and AD dementia (HR 1.76, 95% CI 1.11-2.81) but not with markers of vascular brain injury (WMH, covert brain infarcts or stroke). Higher circulating EFEMP1 concentrations were also cross-sectionally associated with lower total brain (β±SE, -0.28±0.11, p = 0.01) and hippocampal volumes (-0.006±0.003, p = 0.04) and impaired abstract reasoning (Similarities test, -0.18±0.08, p = 0.018 per standard deviation increment in EFEMP1).

CONCLUSION: Elevated circulating EFEMP1 is associated with an increased risk of all-cause and AD dementia, smaller hippocampal and total brain volumes, and poorer cognitive performance. EFEMP1 may play an important biological role in the development of AD dementia. Further studies to validate these findings are warranted.

%B J Alzheimers Dis %V 85 %P 1657-1666 %8 2022 Feb 15 %G eng %N 4 %R 10.3233/JAD-215053 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Association of Serum Vitamin D with the Risk of Incident Dementia and Subclinical Indices of Brain Aging: The Framingham Heart Study. %A Karakis, Ioannis %A Pase, Matthew P %A Beiser, Alexa %A Booth, Sarah L %A Jacques, Paul F %A Rogers, Gail %A DeCarli, Charles %A Vasan, Ramachandran S %A Wang, Thomas J %A Himali, Jayandra J %A Annweiler, Cedric %A Seshadri, Sudha %K Adult %K Aging %K Brain %K Cohort Studies %K Dementia %K Female %K Humans %K Incidence %K Magnetic Resonance Imaging %K Male %K Middle Aged %K Multivariate Analysis %K Neuropsychological Tests %K Regression Analysis %K Risk %K Sensitivity and Specificity %K Vitamin D %X

BACKGROUND: Identifying nutrition- and lifestyle-based risk factors for cognitive impairment and dementia may aid future primary prevention efforts.

OBJECTIVE: We aimed to examine the association of serum vitamin D levels with incident all-cause dementia, clinically characterized Alzheimer's disease (AD), MRI markers of brain aging, and neuropsychological function.

METHODS: Framingham Heart Study participants had baseline serum 25-hydroxyvitamin D (25(OH)D) concentrations measured between 1986 and 2001. Vitamin D status was considered both as a continuous variable and dichotomized as deficient (<10 ng/mL), or at the cohort-specific 20th and 80th percentiles. Vitamin D was related to the 9-year risk of incident dementia (n = 1663), multiple neuropsychological tests (n = 1291) and MRI markers of brain volume, white matter hyperintensities and silent cerebral infarcts (n = 1139).

RESULTS: In adjusted models, participants with vitamin D deficiency (n = 104, 8% of the cognitive sample) displayed poorer performance on Trail Making B-A (β= -0.03 to -0.05±0.02) and the Hooper Visual Organization Test (β= -0.09 to -0.12±0.05), indicating poorer executive function, processing speed, and visuo-perceptual skills. These associations remained when vitamin D was examined as a continuous variable or dichotomized at the cohort specific 20th percentile. Vitamin D deficiency was also associated with lower hippocampal volumes (β= -0.01±0.01) but not total brain volume, white matter hyperintensities, or silent brain infarcts. No association was found between vitamin D deficiency and incident all-cause dementia or clinically characterized AD.

CONCLUSIONS: In this large community-based sample, low 25(OH)D concentrations were associated with smaller hippocampal volume and poorer neuropsychological function.

%B J Alzheimers Dis %V 51 %P 451-61 %8 2016 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/26890771?dopt=Abstract %R 10.3233/JAD-150991