scholarly journals The bidirectional causal effects of brain morphology across the life course and risk of Alzheimers disease: A cross-cohort comparison and Mendelian randomization meta-analysis

2021 ◽  
Author(s):  
Roxanna Korologou-Linden ◽  
Bing Xu ◽  
Elizabeth Coulthard ◽  
Esther Walton ◽  
Alfie Wearn ◽  
...  
Keyword(s):  
Cortical Thickness ◽  
Mendelian Randomization ◽  
Clinical Symptoms ◽  
Brain Morphology ◽  
Cerebral White Matter ◽  
Intracranial Volume ◽  
Alzheimers Disease ◽  
Genetic Liability ◽  
Brain Reserve ◽  
Structural Brain

Neuropathological changes associated with Alzheimers disease (AD) can occur decades before clinical symptoms. We investigated whether neurodevelopment and/or neurodegeneration affects the risk of AD, through reducing structural brain reserve and/or accelerating brain atrophy, respectively. We used bidirectional two-sample Mendelian randomization to estimate the effects of genetic liability to AD on global and regional cortical thickness, total intracranial volume, volume of subcortical structures and cerebral white matter in 36,842 participants aged eight to 81 years across five independent cohorts, and the effects of global and regional cortical thickness and subcortical volumes on AD risk in 94,337 participants. Our findings show that AD risk alleles have an age-dependent effect on a range of cortical and subcortical brain measures that starts in mid-life, in non-clinical populations. Evidence for such effects across childhood and young adulthood is weak. We also found little evidence to suggest brain morphology alters AD risk. Thus, genetic liability to AD is likely to alter mechanisms and/or rates of neurodegeneration, rather than reduce structural brain reserve.

scholarly journals Running in the Family? Structural Brain Abnormalities and IQ in Offspring, Siblings, Parents, and Co-twins of Patients with Schizophrenia

2018 ◽  
Vol 45 (6) ◽  
pp. 1209-1217 ◽  
Author(s):  
Sonja M C de Zwarte ◽  
Rachel M Brouwer ◽  
Andromachi Tsouli ◽  
Wiepke Cahn ◽  
Manon H J Hillegers ◽  
...  
Keyword(s):  
White Matter ◽  
Multiple Comparisons ◽  
Effect Sizes ◽  
Cerebral White Matter ◽  
Intracranial Volume ◽  
Brain Abnormalities ◽  
Total Brain ◽  
Genetic Overlap ◽  
Cortical Gray Matter ◽  
Structural Brain

Abstract Structural brain abnormalities and cognitive deficits have been reported in patients with schizophrenia and to a lesser extent in their first-degree relatives (FDRs). Here we investigated whether brain abnormalities in nonpsychotic relatives differ per type of FDR and how these abnormalities are related to intelligent quotient (IQ). Nine hundred eighty individuals from 5 schizophrenia family cohorts (330 FDRs, 432 controls, 218 patients) were included. Effect sizes were calculated to compare brain measures of FDRs and patients with controls, and between each type of FDR. Analyses were repeated with a correction for IQ, having a nonpsychotic diagnosis, and intracranial volume (ICV). FDRs had significantly smaller ICV, surface area, total brain, cortical gray matter, cerebral white matter, cerebellar gray and white matter, thalamus, putamen, amygdala, and accumbens volumes as compared with controls (ds < −0.19, q < 0.05 corrected). Offspring showed the largest effect sizes relative to the other FDRs; however, none of the effects in the different relative types survived correction for multiple comparisons. After IQ correction, all effects disappeared in the FDRs after correction for multiple comparisons. The findings in FDRs were not explained by having a nonpsychotic disorder and were only partly explained by ICV. FDRs show brain abnormalities that are strongly covarying with IQ. On the basis of consistent evidence of genetic overlap between schizophrenia, IQ, and brain measures, we suggest that the brain abnormalities in FDRs are at least partly explained by genes predisposing to both schizophrenia risk and IQ.

scholarly journals Aging Brain and Hearing: A Mini-Review

2022 ◽  
Vol 13 ◽  
Author(s):  
Yasue Uchida ◽  
Yukiko Nishita ◽  
Rei Otsuka ◽  
Saiko Sugiura ◽  
Michihiko Sone ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Brain Volume ◽  
Clinical Symptoms ◽  
Primary Auditory Cortex ◽  
Brain Morphology ◽  
Aging Brain ◽  
Brain Reserve ◽  
Morphological Studies ◽  
Age Related ◽  
Dementia Research

Brain reserve is a topic of great interest to researchers in aging medicine field. Some individuals retain well-preserved cognitive function until they fulfill their lives despite significant brain pathology. One concept that explains this paradox is the reserve hypothesis, including brain reserve that assumes a virtual ability to mitigate the effects of neuropathological changes and reduce the effects on clinical symptoms flexibly and efficiently by making complete use of the cognitive and compensatory processes. One of the surrogate measures of reserve capacity is brain volume. Evidence that dementia and hearing loss are interrelated has been steadily accumulating, and age-related hearing loss is one of the most promising modifiable risk factors of dementia. Research focused on the imaging analysis of the aged brain relative to auditory function has been gradually increasing. Several morphological studies have been conducted to understand the relationship between hearing loss and brain volume. In this mini review, we provide a brief overview of the concept of brain reserve, followed by a small review of studies addressing brain morphology and hearing loss/hearing compensation, including the findings obtained from our previous study that hearing loss after middle age could affect hippocampal and primary auditory cortex atrophy.

EXPRESS: Effect of genetic liability to visceral adiposity on stroke and its subtypes: a Mendelian randomization study

2021 ◽  
pp. 174749302110062
Author(s):  
Bin Yan ◽  
Jian Yang ◽  
Li Qian ◽  
Fengjie Gao ◽  
Ling Bai ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Ischemic Stroke ◽  
Genome Wide Association Study ◽  
Mendelian Randomization ◽  
Visceral Adiposity ◽  
Large Artery ◽  
Nucleotide Polymorphisms ◽  
Genetic Liability ◽  
A Genome ◽  
Increased Risk

Background: Observational studies have found an association between visceral adiposity and stroke. Aims: The purpose of this study was to investigate the role and genetic effect of visceral adipose tissue (VAT) accumulation on stroke and its subtypes. Methods: In this two-sample Mendelian randomization (MR) study, genetic variants (221 single nucleotide polymorphisms; P<5×10-8) using as instrumental variables for MR analysis was obtained from a genome-wide association study (GWAS) of VAT. The outcome datasets for stroke and its subtypes were obtained from the MEGASTROKE consortium (up to 67,162 cases and 453,702 controls). MR standard analysis (inverse variance weighted method) was conducted to investigate the effect of genetic liability to visceral adiposity on stroke and its subtypes. Sensitivity analysis (MR-Egger, weighted median, MR-PRESSO) were also utilized to assess horizontal pleiotropy and remove outliers. Multi-variable MR analysis was employed to adjust potential confounders. Results: In the standard MR analysis, genetically determined visceral adiposity (per 1 SD) was significantly associated with a higher risk of stroke (odds ratio [OR] 1.30; 95% confidence interval [CI] 1.21-1.41, P=1.48×10-11), ischemic stroke (OR 1.30; 95% CI 1.20-1.41, P=4.01×10-10), and large artery stroke (OR 1.49; 95% CI 1.22-1.83, P=1.16×10-4). The significant association was also found in sensitivity analysis and multi-variable MR analysis. Conclusions: Genetic liability to visceral adiposity was significantly associated with an increased risk of stroke, ischemic stroke, and large artery stroke. The effect of genetic susceptibility to visceral adiposity on the stroke warrants further investigation.

scholarly journals Causal Association between Periodontitis and Parkinson’s Disease: A Bidirectional Mendelian Randomization Study

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 772
Author(s):  
João Botelho ◽  
Vanessa Machado ◽  
José João Mendes ◽  
Paulo Mascarenhas
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Instrumental Variables ◽  
Mendelian Randomization ◽  
Association Studies ◽  
European Ancestry ◽  
Genome Wide Association Studies ◽  
Nucleotide Polymorphisms ◽  
Genetic Liability ◽  
Bidirectional Association

The latest evidence revealed a possible association between periodontitis and Parkinson’s disease (PD). We explored the causal relationship of this bidirectional association through two-sample Mendelian randomization (MR) in European ancestry populations. To this end, we used openly accessible data of genome-wide association studies (GWAS) on periodontitis and PD. As instrumental variables for periodontitis, seventeen single-nucleotide polymorphisms (SNPs) from a GWAS of periodontitis (1817 periodontitis cases vs. 2215 controls) and eight non-overlapping SNPs of periodontitis from an additional GWAS for validation purposes. Instrumental variables to explore for the reverse causation included forty-five SNPs from a GWAS of PD (20,184 cases and 397,324 controls). Multiple approaches of MR were carried-out. There was no evidence of genetic liability of periodontitis being associated with a higher risk of PD (B = −0.0003, Standard Error [SE] 0.0003, p = 0.26). The eight independent SNPs (B = −0.0000, SE 0.0001, p = 0.99) validated this outcome. We also found no association of genetically primed PD towards periodontitis (B = −0.0001, SE 0.0001, p = 0.19). These MR study findings do not support a bidirectional causal genetic liability between periodontitis and PD. Further GWAS studies are needed to confirm the consistency of these results.

scholarly journals Arterial stiffness and progression of cerebral white matter hyperintensities in patients with type 2 diabetes and matched controls: a 5-year cohort study

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Kristian L. Funck ◽  
Esben Laugesen ◽  
Pernille Høyem ◽  
Brian Stausbøl-Grøn ◽  
Won Y. Kim ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Cohort Study ◽  
White Matter ◽  
Arterial Stiffness ◽  
White Matter Hyperintensities ◽  
Cerebrovascular Diseases ◽  
Study Data ◽  
Cerebral White Matter ◽  
Intracranial Volume

Abstract Background Stroke is a serious complication in patients with type 2 diabetes (T2DM). Arterial stiffness may improve stroke prediction. We investigated the association between carotid-femoral pulse wave velocity [PWV] and the progression of cerebral white matter hyperintensities (WMH), a marker of stroke risk, in patients with T2DM and controls. Methods In a 5-year cohort study, data from 45 patients and 59 non-diabetic controls were available for analysis. At baseline, participants had a mean (± SD) age of 59  ±  10 years and patients had a median (range) diabetes duration of 1.8 (0.8–3.2) years. PWV was obtained by tonometry and WMH volume by an automated segmentation algorithm based on cerebral T2-FLAIR and T1 MRI (corrected by intracranial volume, cWMH). High PWV was defined above 8.94 m/s (corresponding to the reference of high PWV above 10 m/s using the standardized path length method). Results Patients with T2DM had a higher PWV than controls (8.8  ±  2.2 vs. 7.9  ±  1.4 m/s, p  <  0.01). WMH progression were similar in the two groups (p  =  0.5). One m/s increase in baseline PWV was associated with a 16% [95% CI 1–32%], p  <  0.05) increase in cWMH volume at 5 years follow-up after adjustment for age, sex, diabetes, pulse pressure and smoking. High PWV was associated with cWMH progression in the combined cohort (p  <  0.05). We found no interaction between diabetes and PWV on cWMH progression. Conclusions PWV is associated with cWMH progression in patients with type 2 diabetes and non-diabetic controls. Our results indicate that arterial stiffness may be involved early in the pathophysiology leading to cerebrovascular diseases.

scholarly journals Cortical Volume, Thickness, and Surface Area in the Motoric Cognitive Risk Syndrome

2021 ◽  
pp. 1-14
Author(s):  
Helena M. Blumen ◽  
Emily Schwartz ◽  
Gilles Allali ◽  
Olivier Beauchet ◽  
Michele Callisaya ◽  
...  
Keyword(s):  
Surface Area ◽  
Sex Education ◽  
Cortical Thickness ◽  
Clinical Stage ◽  
White Matter Lesions ◽  
Cortical Atrophy ◽  
Intracranial Volume ◽  
Cortical Volume ◽  
Cognitive Risk ◽  
Cognitive Complaint

Background: The motoric cognitive risk (MCR) syndrome is a pre-clinical stage of dementia characterized by slow gait and cognitive complaint. Yet, the brain substrates of MCR are not well established. Objective: To examine cortical thickness, volume, and surface area associated with MCR in the MCR-Neuroimaging Consortium, which harmonizes image processing/analysis of multiple cohorts. Methods: Two-hundred MRIs (M age 72.62 years; 47.74%female; 33.17%MCR) from four different cohorts (50 each) were first processed with FreeSurfer 6.0, and then analyzed using multivariate and univariate general linear models with 1,000 bootstrapped samples (n-1; with resampling). All models adjusted for age, sex, education, white matter lesions, total intracranial volume, and study site. Results: Overall, cortical thickness was lower in individuals with MCR than in those without MCR. There was a trend in the same direction for cortical volume (p = 0.051). Regional cortical thickness was also lower among individuals with MCR than individuals without MCR in prefrontal, insular, temporal, and parietal regions. Conclusion: Cortical atrophy in MCR is pervasive, and include regions previously associated with human locomotion, but also social, cognitive, affective, and motor functions. Cortical atrophy in MCR is easier to detect in cortical thickness than volume and surface area because thickness is more affected by healthy and pathological aging.

scholarly journals Dynamic Regional Brain Atrophy Rates in the First Year After Ischemic Stroke

Stroke ◽  
2020 ◽  
Vol 51 (9) ◽  
Author(s):  
Amy Brodtmann ◽  
Mohamed Salah Khlif ◽  
Natalia Egorova ◽  
Michele Veldsman ◽  
Laura J. Bird ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cortical Thickness ◽  
Brain Atrophy ◽  
Brain Volume ◽  
Linear Mixed Effect Model ◽  
First Year ◽  
Intracranial Volume ◽  
Mixed Effect ◽  
Time Points ◽  
Regional Brain

Background and Purpose: Brain atrophy can be regarded as an end-organ effect of cumulative cardiovascular risk factors. Accelerated brain atrophy is described following ischemic stroke, but it is not known whether atrophy rates vary over the poststroke period. Examining rates of brain atrophy allows the identification of potential therapeutic windows for interventions to prevent poststroke brain atrophy. Methods: We charted total and regional brain volume and cortical thickness trajectories, comparing atrophy rates over 2 time periods in the first year after ischemic stroke: within 3 months (early period) and between 3 and 12 months (later period). Patients with first-ever or recurrent ischemic stroke were recruited from 3 Melbourne hospitals at 1 of 2 poststroke time points: within 6 weeks (baseline) or 3 months. Whole-brain 3T magnetic resonance imaging was performed at 3 time points: baseline, 3 months, and 12 months. Eighty-six stroke participants completed testing at baseline; 125 at 3 months (76 baseline follow-up plus 49 delayed recruitment); and 113 participants at 12 months. Their data were compared with 40 healthy control participants with identical testing. We examined 5 brain measures: hippocampal volume, thalamic volume, total brain and hemispheric brain volume, and cortical thickness. We tested whether brain atrophy rates differed between time points and groups. A linear mixed-effect model was used to compare brain structural changes, including age, sex, years of education, a composite cerebrovascular risk factor score, and total intracranial volume as covariates. Results: Atrophy rates were greater in stroke than control participants. Ipsilesional hemispheric, hippocampal, and thalamic atrophy rates were 2 to 4 times greater in the early versus later period. Conclusions: Regional atrophy rates vary over the first year after stroke. Rapid brain volume loss in the first 3 months after stroke may represent a potential window for intervention. Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02205424.

Abstract 47: White Matter Atrophy in Cerebral Amyloid Angiopathy

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Panagiotis Fotiadis ◽  
Aaron Schultz ◽  
Trey Hedden ◽  
Sergi Martinez-Ramirez ◽  
Yael Reijmer ◽  
...  
Keyword(s):  
White Matter ◽  
Cerebral Amyloid Angiopathy ◽  
Cortical Thickness ◽  
Tissue Loss ◽  
White Matter Hyperintensity ◽  
Aging Brain ◽  
Amyloid Angiopathy ◽  
Intracranial Volume ◽  
White Matter Volume ◽  
Cerebral Amyloid

Background/Purpose: Cerebral Amyloid Angiopathy (CAA) leads to leukoaraiosis, lacunar infarcts and cortical tissue loss. We hypothesized that CAA is also associated with white matter atrophy (WMA). Methods: We have compared volumetric multimodal MRIs from 72 prospectively enrolled non-demented patients with probable CAA (per Boston criteria), to 3 other well-studied cohorts: 289 Healthy Controls (HC) from the Harvard Aging Brain (HAB) study, 231 HC and 198 patients with AD from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Validated FreeSurfer algorithms were used to calculate White Matter Volume (WMV), white matter hyperintensity volume (WMHv), and cortical thickness. Microbleeds (MBs) were counted on SWI-MRI. Measures were obtained from the contralateral hemisphere if intracerebral hemorrhage present. All volumes were corrected for total intracranial volume (ICV), so reported as percent of ICV. Results: The CAA patients were significantly younger (mean age: 70.1) compared to both HC cohorts (ADNI-HC: 76.0, p<0.001, HAB-HC: 73.8, p < 0.001), and to patients with AD (75.5, p < 0.001). Despite being younger, patients with CAA presented significantly lower global WMV (28% ± 2.6) than both ADNI-HC (29.2% ± 2.2, p < 0.001), HAB-HC (29.0% ± 2.5, p = 0.001), and patients with AD (28.7% ± 2.2, p = 0.02) [Figure]. The association persisted after correcting for age, gender and WMHv. Within the CAA cohort, there was a negative correlation between WMV and lobar MB counts (rho = -0.26, p = 0.03), it remained significant after correcting for age, gender, WMHv (p=0.016). There were no significant associations however between WMV and neither WMHv, nor cortical thickness (both p>0.2). Conclusions: Patients with CAA show WMA when compared to older HC and AD. WMA independently correlates with MBs, a marker of CAA severity. Consistent spatial patterns of atrophy especially in posterior regions when compared to both HC and AD [Figure] might represent the “WMA signature of CAA”.

scholarly journals Blood-based bioenergetic profiling is related to differences in brain morphology in African Americans with Type 2 diabetes

2018 ◽  
Vol 132 (23) ◽  
pp. 2509-2518 ◽  
Author(s):  
Gargi Mahapatra ◽  
S. Carrie Smith ◽  
Timothy M. Hughes ◽  
Benjamin Wagner ◽  
Joseph A. Maldjian ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
White Matter ◽  
African Americans ◽  
Mitochondrial Function ◽  
Brain Morphology ◽  
Intracranial Volume ◽  
Peripheral Blood Mononuclear ◽  
Relationship Of ◽  
The Relationship

Blood-based bioenergetic profiling has promising applications as a minimally invasive biomarker of systemic bioenergetic capacity. In the present study, we examined peripheral blood mononuclear cell (PBMC) mitochondrial function and brain morphology in a cohort of African Americans with long-standing Type 2 diabetes. Key parameters of PBMC respiration were correlated with white matter, gray matter, and total intracranial volumes. Our analyses indicate that these relationships are primarily driven by the relationship of systemic bioenergetic capacity with total intracranial volume, suggesting that systemic differences in mitochondrial function may play a role in overall brain morphology.

Cognitive Deficits and Clinical Symptoms with Hippocampal Subfields in First-Episode and Never-Treated Patients with Schizophrenia

2020 ◽  
Vol 31 (1) ◽  
pp. 89-96
Author(s):  
Mei Hong Xiu ◽  
XiaoE Lang ◽  
Da Chun Chen ◽  
Bo Cao ◽  
Thomas R Kosten ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Cognitive Deficits ◽  
Clinical Symptoms ◽  
Molecular Layer ◽  
Verbal Learning ◽  
Multivariate Regression Analysis ◽  
Granule Cell Layer ◽  
First Episode ◽  
Intracranial Volume ◽  
Hippocampal Subfields

Abstract Memory dysfunction and associated hippocampal disturbances play crucial roles in cognitive impairment of schizophrenia. To examine the relationships between cognitive function and the hippocampal subfields (HSs) in first-episode never-treated (FENT) schizophrenia patients, the HSs were segmented in 39 FENT patients and 30 healthy controls using a state-of the-art automated algorithm. We found no significant differences in any HSs between the patients and controls. However, multivariate regression analysis showed that the left cornu ammonis 1 (CA1), left hippocampal tail, left presubiculum, and right molecular layer contributed 40% to the variance of the PANSS negative symptom score. After adjusting for sex, age, education, and intracranial volume, the partial correlation analysis showed that the volumes of left CA1, CA3, CA4, molecular layer, granule cell layer and both left and right subiculum were negatively correlated with the MATRICS consensus cognitive battery (MCCB) Hopkins Verbal Learning Test (HVLT). Multiple regression analysis showed that the left CA1 and CA3 hippocampal abnormalities contributed 66% to the variance of the HVLT. Our results suggest no detectable HS deficits were found in FENT schizophrenia patients. However, the HSs may be involved in the symptoms and cognitive deficits of schizophrenia patients in the early phase of their illness.

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