Smaller Hippocampal Volumes Research Articles

Haptoglobin 1-1 Genotype Modulates the Association of Glycemic Control With Hippocampal Volume in Elderly Individuals With Type 2 Diabetes.

Recent evidence suggests that glycemic control is associated with cognitive function in older patients with type 2 diabetes who are carriers of the haptoglobin (Hp) 1-1 genotype compared with noncarriers. We assessed whether poor glycemic control in Hp 1-1 carriers is more strongly associated with smaller hippocampal volume than in noncarriers. Hippocampal volume was generated from high-resolution structural T1 MRI obtained for 224 participants (28 Hp 1-1 carriers [12.5%] and 196 noncarriers [87.5%]) from the Israel Diabetes and Cognitive Decline (IDCD) study, who had a mean (SD) number of years in the Maccabi Healthcare Services (MHS) registry of 8.35 (2.63) and a mean (SD) HbA1c level of 6.66 (0.73)% [49 mmol/mol]. A stronger negative association between right hippocampal volume and HbA1c was found in patients with the Hp 1-1 genotype, with a 0.032-mL decrease in right hippocampal volume per 14% increase in HbA1c (P = 0.0007) versus a 0.009-mL decrease in Hp 1-1 noncarriers (P = 0.047), after adjusting for total intracranial volume, age, sex, follow-up years in the registry, and cardiovascular factor (interaction, P = 0.025). This indicates that 29.66% of the total variance in right hippocampal volume is explained by HbA1c levels among Hp 1-1 carriers and that 3.22% is explained by HbA1c levels among Hp 1-1 noncarriers. Our results suggest that the hippocampus of Hp 1-1 carriers may be more vulnerable to the insults of poor glycemic control.

Finding of increased caudate nucleus in patients with Alzheimer's disease.

A recently published study using an automated MRI volumetry method (NeuroQuant®) unexpectedly demonstrated larger caudate nucleus volume in patients with Alzheimer's disease dementia (AD) compared to patients with subjective and mild cognitive impairment (SCI and MCI). The aim of this study was to explore this finding. The caudate nucleus and the hippocampus volumes were measured (both expressed as ratios of intracranial volume) in a total of 257 patients with SCI and MCI according to the Winblad criteria and AD according to ICD-10 criteria. Demographic data, cognitive measures, and APOE-ɛ4 status were collected. Compared with non-dementia patients (SCI and MCI), AD patients were older, more of them were female, and they had a larger caudate nucleus volume and smaller hippocampus volume (P<.001). In multiple linear regression analysis, age and female sex were associated with larger caudate nucleus volume, but neither diagnosis nor memory function was. Age, gender, and memory function were associated with hippocampus volume, and age and memory function were associated with caudate nucleus/hippocampus ratio. A larger caudate nucleus volume in AD patients was partly explained by older age and being female. These results are further discussed in the context of (1) the caudate nucleus possibly serving as a mechanism for temporary compensation; (2) methodological properties of automated volumetry of this brain region; and (3) neuropathological alterations. Further studies are needed to fully understand the role of the caudate nucleus in AD.

HIPPOCAMPAL INTEGRITY IN SWEDISH WOMEN WITH BILATERAL SALPINGO-OOPHORECTOMY PRIOR TO NATURAL MENOPAUSE

Oophorectomy prior to natural menopause places women at increased risk of dementia and/or Alzheimer's disease (AD). Recent findings from our Toronto group reveal a negative association between oophorectomy prior to natural menopause and verbal memory in middle-aged women. We have also found a positive association between estrogen levels and verbal recall. Taken together, these findings support previous work suggesting that oophorectomy, leading to reduced levels of estrogens, is detrimental to verbal memory. Estrogen withdrawal has also been correlated with reduced hippocampal volume and reduced hippocampal resting functional connectivity (FC), both early AD biomarkers. Thus, we wondered whether hippocampal volume and resting functional connectivity would be reduced in women with oophorectomy prior to natural menopause. In order to determine this, we recruited healthy, Swedish women (30 and 55 years) with the breast cancer mutation gene (BRCA1/2) who had a bilateral salpingo-oophorectomy (BSO) prior to natural menopause. Most women were between 1–7 years post-BSO and at least 6 months post-cancer treatment or had not had cancer. Using magnetic resonance imaging (3T scanner, Phillips) we measured functional resting state over 10 minutes and volume with a T1 structural scan. We collected urine in order to determine estrogen and progesterone levels. We hypothesize that women with BSO will have structural and functional hippocampal changes compared to age matched controls. We predict that women with BSO will have smaller hippocampal volumes and reduced hippocampal FC. We further predict that lower levels of estrogens will correlate with these brain changes. Neuroimaging and endocrine analyses are ongoing. AD affects women in greater numbers and one possibility is that oophorectomy prior to natural menopause contributes to these numbers. Determining whether or not these women show the earliest biomarkers for AD will increase our understanding of estrogen withdrawal's effects on brain health as well as its importance for healthy brain aging. Importantly, results of this study will inform us on the early brain changes in a population at greater risk of AD.

ASSOCIATION OF PSYCHOSOCIAL WORK STRESS WITH COGNITIVE DECLINE AND BRAIN STRUCTURE DIFFERENCES

Evidence on the influence of psychosocial work stress on cognitive function and brain structure is limited. This study examined whether work-related stress is associated with structural brain changes and cognitive decline in old age. In a population-based prospective cohort study, 2876 dementia-free participants aged ≥60 years were followed-up for up to 9 years. A subsample (n=436) underwent brain magnetic resonance imaging (MRI) at baseline. Global cognitive function was measured by the Mini-Mental State Examination at baseline and all follow-ups. Levels of job control and demands in the longest held job over the whole working life were assessed by a validated matrix. Data were analyzed using mixed-effects linear regression. People with low levels of job control and demands exhibited greater cognitive decline (β: -0.13, 95% CI: -0.19 to -0.07; β: -0.10, 95% CI: -0.16 to -0.04), compared to those with high levels. Relative to persons who had active job strain, faster cognitive decline was found in those who had high job strain (β: -0.11, 95% CI: -0.18 to -0.05,) and passive job strain (β: -0.16, 95% CI: -0.23 to -0.09). MRI data showed that low levels of job demands and passive job strain were both related to smaller total hippocampal volume (β: -0.23, 95% CI: -0.39 to -0.08; β: -0.19, 95% CI: -0.37 to -0.01). Work-related psychosocial stress is associated with smaller hippocampal volume and may accelerate cognitive decline even in the eight decade of life, suggesting that neural alterations play a role in the work stress-cognitive decline link.

Cortical thickness and subcortical structure volume abnormalities in patients with major depression with and without anxious symptoms.

BackgroundAnxious depression is one of the common subtypes of major depressive disorder (MDD). Clinically, patients with anxious depression exhibit more severe depressive symptoms than patients with nonanxious depression. The aim of the present study was to explore the common and differing cortical and subcortical structural changes between patients with anxious and nonanxious depression.MethodsPatients were placed into one of three groups: the anxious depression group (MDD patients with high levels of anxiety symptoms, n = 23), the nonanxious depression group (n = 22), and healthy controls (n = 43) that were matched for age, sex, and education level. All participants underwent T1‐weighted MRI. The Freesurfer, which uses a set of automated sequences to analyze the abnormal changes of cortical thickness, cortical and subcortical structures, was used to process the T1 images.ResultsCompared to controls, MDD patients showed thinner cortical thickness in the left inferior temporal, the right superior temporal, and the right parsorbitalis, and a smaller volume of the left hippocampus. Compared to nonanxious depression, anxious depressive patients showed a cortical thinning of the left superior frontal and right superior temporal, as well as the right lingual, and significantly increased subcortical volume of the bilateral caudate nuclei. Correlation analysis showed that the volumes of the bilateral caudate nuclei were directly proportional to the anxiety/somatization factor score.ConclusionsThese findings suggest that smaller hippocampal volume and atrophic prefrontal and temporal cortices might be a common pattern of cortical and subcortical alterations in patients with depression and/or anxiety. However, the change in the caudate nucleus volume may be indicative of anxious depression and may potentially be used to distinguish anxious from nonanxious depression.

Effect of APOE Genotype on Amyloid Deposition, Brain Volume, and Memory in Cognitively Normal Older Individuals.

The association between the apolipoprotein E (APOE) ɛ4 allele and high risk of developing Alzheimer's disease (AD) dementia before the age of 80 has been recognized for over 30 years. However, the timing and mode of action of APOE is not understood, nor has there been a detailed analysis of the effect of APOE genotype on memory, hippocampal volume, and amyloid-β (Aβ) levels in cognitively normal adults. Examine the effect of APOE allelic genotype on the relationship between Aβ levels, hippocampal volume, and memory in cognitively normal adults. This is a cross-sectional study of 989 cognitively normal older adults enrolled in the Australian Imaging, Biomarkers and Lifestyle (AIBL) study, all of whom underwent APOE genotyping and memory assessment. A subset of this group underwent PET neuroimaging for Aβ (n = 585) and MRI for hippocampal volume (n = 303). APOEɛ4 homozygotes (ɛ4/ɛ4) showed significantly worse episodic memory and higher Aβ levels than ɛ4 heterozygotes. The relationship between increasing Aβ levels and worse episodic memory was significant for ɛ3 homozygotes (ɛ3/ɛ3), ɛ4 heterozygotes, and strongest for ɛ4 homozygotes. There were no differences in hippocampal volume between APOE groups; the relationship between smaller hippocampal volume and worse episodic memory was significant only for ɛ4 homozygotes. APOE acts in a co-dominant fashion on Aβ levels, episodic memory, and hippocampal volume in cognitively normal older adults. APOEɛ4 is central to the events that lead to AD in cognitively normal older adults, likely through a quantitative role in the disruption of Aβ clearance.

The Association between Montreal Cognitive Assessment Memory Scores and Hippocampal Volume in a Neurodegenerative Disease Sample.

Despite widespread use, there have been few investigations into the neuroanatomical correlates of the Montreal Cognitive Assessment (MoCA). In a sample of 138 consecutive patients presenting with cognitive complaints, we report significant correlations between lower MoCA memory scores and smaller hippocampal volumes (r = 0.36–0.41, p < 0.001). We also report that the newly devised memory index score, designed to better capture encoding deficits than the standard delayed recall score, was not significantly better for predicting hippocampal volume. These initial results suggest that poor performance on the MoCA’s memory section should prompt further evaluation for hippocampal atrophy.

NEUROIMAGING OF SUBCORTICAL BRAIN VOLUME ALTERATIONS IN PEADIATRIC AND ADULT OBSESSIVE-COMPULSIVE DISORDER: Preliminary findings from the ENIGMA Obsessive-Compulsive Disorder working group

Objective Structural MRI studies investigating the neural correlates of OCD have been numerous. Nevertheless, results of these studies have not always been consistent. Variability in study results may partially be explained by small sample sizes resulting in limited statistical power, clinical heterogeneity between patient samples, and methodological differences between studies. In this context, we initiated the ENIGMA-OCD working group. Our aim is to identify robust imaging markers of OCD using coordinated standardized image processing and statistical analysis protocols. Here, we perform the largest study to date of subcortical brain volumes in OCD patients and healthy controls using an individual participant data (IPD) based meta-analysis approach. Methods Structural T1-weightred MRI scans from 3722 subjects (361 paediatric OCD patients, 1574 adult OCD patients, 314 paediatric controls and 1473 adult controls) from 25 research sites worldwide were analysed using FreeSurfer 5.3. Segmentations of subcortical regions, lateral ventricles and total intracranial volumes (ICV) were visually inspected for accuracy and compared between patients and controls using regression models controlling for age, sex, and ICV. Each site followed standardized protocols designed to facilitate harmonized image analysis across multiple sites. Separate stratified analyses assessing effects of age of onset, disease duration, symptom dimensions, and symptom severity were performed. Results were combined in random-effects meta-analysis models. Meta-regression analyses were used to test whether mean age of each sample and field strength of MR images explained a significant proportion of the variance in effect seizes across sites in the meta-analysis. Results were considered significant if they exceeded a Bonferroni corrected P-value threshold (p=0.05/9 regions = 5.6x10-3). Results Adult patients, compared to adult controls, had significantly smaller hippocampal volumes (Cohen’s d= -0.15, p= 7.4x10-4) and bigger pallidum volumes (d= 0.16, p=1.8x10-3). This effect was notably stronger in medicated patients versus controls (d= -0.29, p=2.8x10-6 and d= 0.24, p=2.5x10-4, respectively). The hippocampus effect seemed to be driven by patients with comorbid depression d= 0.29, p=4.8x10-5). Also, symptom severity was associated with a smaller hippocampus (R= -0.08, p=4.9x10-3). Sample characteristics such as mean age and field strength did not moderate brain volume alterations. None of the subcortical structures, neither ICV nor lateral ventricles were significantly different between paediatric OCD cases and controls after Bonferroni correction. However, unmedicated paediatric patients show bigger thalamus volumes (d= 0.40, p=9.0x10-4) relative to control children. Additionally, longer disease duration and ad trend-significant level, younger age of onset was associated with bigger thalamus volume in paediatric OCD (d= 0.18, p=5.1x10-3 and d= -0.17, p=5.7x10-3, respectively). Conclusion Results of this subcortical meta-analysis indicate a key role of the pallidum in the pathophysiology of OCD. Different ENIGMA disease working groups, such as MDD, schizophrenia, and bipolar disorder also observed hippocampal abnormalities, which suggests that our findings regarding hippocampal abnormalities are aspecific for OCD. In addition, we showed that unmedicated paediatric OCD patients have significantly enlarged thalamus volumes. Moreover, our findings suggest a different pattern of subcortical abnormalities in paediatric OCD patients and adult OCD patients in line with the developmental nature of the disease.

Repeated exposure to sucrose for procedural pain in mouse pups leads to long-term widespread brain alterations.

Oral sucrose is administered routinely to reduce pain of minor procedures in premature infants and is recommended as standard care in international guidelines. No human or animal studies on effects of early repeated sucrose exposure on long-term brain development have been done in the context of pain. We evaluated the effects of repeated neonatal sucrose treatment before an intervention on long-term brain structure in mouse pups. Neonatal C57Bl/6J mice (n = 109) were randomly assigned to one of 2 treatments (vehicle vs sucrose) and one of 3 interventions (handling, touch, or needle-prick). Mice received 10 interventions daily from postnatal day 1 to 6 (P1-6). A dose of vehicle or 24% sucrose was given orally 2 minutes before each intervention. At P85-95, brains were scanned using a multichannel 7.0 T MRI. Volumes of 159 independent brain regions were obtained. Early repetitive sucrose exposure in mice (after correcting for whole brain volume and multiple comparisons) lead to smaller white matter volumes in the corpus callosum, stria terminalis, and fimbria (P < 0.0001). Cortical and subcortical gray matter was also affected by sucrose with smaller volumes of hippocampus and cerebellum (P < 0.0001). These significant changes in adult brain were found irrespective of the type of intervention in the neonatal period. This study provides the first evidence of long-term adverse effects of repetitive sucrose exposure and raises concerns for the use of this standard pain management practice during a period of rapid brain development in very preterm infants.

Associations Between Left Ventricular Dysfunction and Brain Structure and Function: Findings From the SABRE (Southall and Brent Revisited) Study.

BackgroundSubclinical left ventricular (LV) dysfunction has been inconsistently associated with early cognitive impairment, and mechanistic pathways have been poorly considered. We investigated the cross‐sectional relationship between LV dysfunction and structural/functional measures of the brain and explored the role of potential mechanisms.Method and ResultsA total of 1338 individuals (69±6 years) from the Southall and Brent Revisited study underwent echocardiography for systolic (tissue Doppler imaging peak systolic wave) and diastolic (left atrial diameter) assessment. Cognitive function was assessed and total and hippocampal brain volumes were measured by magnetic resonance imaging. Global LV function was assessed by circulating N‐terminal pro–brain natriuretic peptide. The role of potential mechanistic pathways of arterial stiffness, atherosclerosis, microvascular disease, and inflammation were explored. After adjusting for age, sex, and ethnicity, lower systolic function was associated with lower total brain (beta±standard error, 14.9±3.2 cm3; P<0.0001) and hippocampal volumes (0.05±0.02 cm3, P=0.01). Reduced diastolic function was associated with poorer working memory (−0.21±0.07, P=0.004) and fluency scores (−0.18±0.08, P=0.02). Reduced global LV function was associated with smaller hippocampal volume (−0.10±0.03 cm3, P=0.004) and adverse visual memory (−0.076±0.03, P=0.02) and processing speed (0.063±0.02, P=0.006) scores. Separate adjustment for concomitant cardiovascular risk factors attenuated associations with hippocampal volume and fluency only. Further adjustment for the alternative pathways of microvascular disease or arterial stiffness attenuated the relationship between global LV function and visual memory.ConclusionsIn a community‐based sample of older people, measures of LV function were associated with structural/functional measures of the brain. These associations were not wholly explained by concomitant risk factors or potential mechanistic pathways.

The Relationship between Cerebral Small Vessel Disease, Hippocampal Volume and Cognitive Functioning in Patients with COPD: An MRI Study

The neural correlates of cognitive impairment in chronic obstructive pulmonary disease (COPD) are not yet understood. Structural brain abnormalities could possibly be associated with the presence of cognitive impairment through cigarette smoke, inflammation, vascular disease, or hypoxemia in these patients. This study aimed to investigate whether macrostructural brain magnetic resonance imaging (MRI) features of cerebral small vessel disease (SVD) and hippocampal volume (HCV) are related to cognitive performance in patients with COPD. A subgroup of cognitively high and low-performing COPD patients of the COgnitive-PD study, underwent a brain 3T MRI. SVD as a marker of vascular damage was assessed using qualitative visual rating scales. HCV as a marker of neurodegeneration was assessed using the learning embedding for atlas propagation (LEAP) method. Features of SVD and HCV were compared between cognitively high and low-performing individuals using Mann Whitney U tests and independent samples t-tests, respectively. No group differences were reported between 25 high-performing (mean age 60.3 (standard deviation [SD] 9.7) years; 40.0% men; forced expiratory volume in first second [FEV1] 50.1% predicted) and 30 low-performing patients with COPD (mean age 60.6 (SD 6.8) years; 53.3% men; FEV1 55.6% predicted) regarding demographics, clinical characteristics, comorbidities and the presence of the SVD features and HCV. To conclude, the current study does not provide evidence for a relationship between cerebral SVD and HCV and cognitive functioning in patients with COPD. Additional studies will be needed to determine other possible mechanisms of cognitive impairment in patients with COPD, including microstructural brain changes and inflammatory-, hormonal-, metabolic- and (epi)genetic factors.

Cued memory decline in biomarker-defined preclinical Alzheimer disease.

To determine whether a decline in cued recall is observable in the preclinical stage of Alzheimer disease (AD) in clinically normal older adults with elevated β-amyloid (Aβ) burden on PET imaging. Clinically normal older adults underwent baseline neuroimaging (PET to assess Aβ+/- status and MRI) and annual neuropsychological testing. Cox proportional hazards models were used to assess the relative risk of cued memory decline (drop of 1, 2, 3, or 4 points on the total score of the Free and Cued Selective Reminding Test) in relation to neuroimaging measures, functional status, age, sex, and education. A total of 276 older adults (Clinical Dementia Rating = 0, mean Mini-Mental State Examination score = 29 ± 1.06) were followed up for a mean of 3.6 ± 1.2 years. Despite the infrequency of cued memory decline (only 19% of participants scored ≤46/48 in total recall by year 3), Aβ+ participants were 3.55 times (95% confidence interval = 1.77-7.12) more likely to exhibit decline in total recall (≤46/48) compared with their Aβ- peers. Furthermore, Aβ+ participants who scored ≤46/48 had smaller hippocampal volumes (t = 3.37, p = 0.001) and evidence of early functional decline, i.e., greater risk of progression to global Clinical Dementia Rating of 0.5 (χ2 = 14.30, p < 0.001), compared with their Aβ+ peers with intact total recall. Cued memory decline in healthy older adults may be particularly indicative of Aβ-related decline during the preclinical stage of AD and useful for identifying Aβ+ clinically normal individuals at greatest risk of short-term clinical progression.

Specific patterns of whole-brain structural covariance of the anterior and posterior hippocampus in young APOE ε4 carriers

Apolipoprotein E (APOE) ε4 has been associated with smaller hippocampal volumes in healthy aging, while findings in young adults are inconclusive. Previous studies have mostly used univariate methods, and without considering potential anterior/posterior differences. Here, we used a multivariate method, partial least squares, and assessed whole-brain structural covariance of the anterior (aHC) and posterior (pHC) hippocampus in young adults (n=97) as a function of APOE ε4 status and sex. Two significant patterns emerged: (1) specific structural covariance of the aHC with frontal regions, temporal and occipital areas in APOE ε4 women, whereas the volume of both the aHC and pHC in all other groups co-varied with frontal, parietal and cerebellar areas; and (2) opposite structural covariance of the pHC in ε4 carriers compared to the aHC in non-carriers, with the pHC of ε4 carriers covarying with parietal and frontal areas, and the aHC of ε4 non-carriers covarying with motor areas and the middle frontal gyrus. APOE ε4 has in young adults been associated with better episodic and spatial memory, functions involving the aHC and pHC, respectively. We found no associations between structural covariance and performance, suggesting that other factors underlie the performance differences seen between carriers and non-carriers. Our findings indicate that APOE ε4 carriers and non-carriers differ in hippocampal organization and that there are differences as a function of sex and hippocampal segment. They stress the need to consider the hippocampus as a heterogeneous structure, and highlight the benefits of multivariate methods in assessing group differences in the brain.

Late-Life Depression, Hippocampal Volumes, and Hypothalamic-Pituitary-Adrenal Axis Regulation: A Systematic Review and Meta-analysis

BackgroundWe systematically reviewed and meta-analyzed the association of late-life depression (LLD) with hippocampal volume (HCV) and total brain volume (TBV), and of cortisol levels with HCV, including subgroup analyses of depression characteristics and methodological aspects. MethodsWe searched PubMed and Embase for original studies that examined the cross-sectional relationship between LLD and HCV or TBV, and 46 studies fulfilled the inclusion criteria. Standardized mean differences (Hedges’ g) between LLD and control subjects were calculated from crude or adjusted brain volumes using random effects. Standardized Fisher transformations of the correlations between cortisol levels and HCVs were calculated using random effects. ResultsWe included 2702 LLD patients and 11,165 control subjects from 35 studies examining HCV. Relative to control subjects, patients had significantly smaller HCVs (standardized mean difference = –0.32 [95% confidence interval, –0.44 to –0.19]). Subgroup analyses showed that late-onset depression was more strongly associated with HCV than early-onset depression. In addition, effect sizes were larger for case-control studies, studies with lower quality, and studies with small sample size, and were almost absent in cohort studies and studies with larger sample sizes. For TBV, 2523 patients and 7880 control subjects from 31 studies were included. The standardized mean difference in TBV between LLD and control subjects was –0.10 (95% confidence interval, –0.16 to –0.04). Of the 12 studies included, higher levels of cortisol were associated with smaller HCV (correlation = –0.11 [95% confidence interval, –0.18 to –0.04]). ConclusionsWhile an overall measure of LLD may be associated with smaller HCVs, differentiating clinical aspects of LLD and examining methodological issues show that this relationship is not straightforward.

Beta-amyloid and Cortical Thickness Reveal Racial Disparities in Preclinical Alzheimer's Disease.

African Americans are two to four times more likely to develop dementia as Non-Hispanic Whites. This increased risk among African Americans represents a critical health disparity that affects nearly 43 million Americans. The present study tested the hypothesis that older African Americans with elevated beta-amyloid would show greater neurodegeneration (smaller hippocampal volumes and decreased cortical thickness) than older Non-Hispanic Whites with elevated beta-amyloid. Data from the Harvard Aging Brain Study (HABS) were used to form a group of older African Americans and two matched groups of Non-Hispanic White adults. Amyloid-positive African Americans had decreased cortical thickness in most of the Alzheimer's disease (AD) signature regions compared with amyloid-positive Non-Hispanic Whites. This factor was negatively correlated with age and white matter hypointensities. Using support vector regression, we also found some evidence that African Americans have an older “brain age” than Non-Hispanic Whites. These findings suggest that African Americans might be more susceptible to factors causing neurodegeneration, which then might accelerate the rate of a diagnosis of AD.

Magnetic Resonance Volumetry: Prediction of Subjective Memory Complaints and Mild Cognitive Impairment, and Associations with Genetic and Cardiovascular Risk Factors

Background/Aims: Subjective memory complaints (SMC) are strong predictors of mild cognitive impairment (MCI) and subsequent Alzheimer’s disease. Our aims were to see if fully automated cerebral MR volume measurements could distinguish subjects with SMC and MCI from controls, and if probable parental late-onset Alzheimer’s disease (LOAD), apolipoprotein E ε4 genotype, total plasma homocysteine, and cardiovascular risk factors were associated with MR volumetric findings. Methods: 198 stroke-free subjects comprised the control (n = 58), the SMC (n = 25) and the MCI (n = 115) groups. Analysis of covariance and receiver operating characteristic curve was used to see if MR volumetry distinguished subjects with SMC and MCI from controls. Results: Subjects with SMC and MCI had significantly larger lateral ventricles and smaller hippocampal volumes than controls. The area under the curve in subjects with SMC and MCI compared to that of controls was less than 0.68 for all volumes of intracranial structures. There was an interaction between sex and probable parental LOAD for hippocampal volume, with a significant association between probable parental LOAD and hippocampal volume in women. Conclusions: Fully automated MR volumetry can distinguish subjects with SMC and MCI from controls in a general population, but insufficiently to assume a clear clinical role. Research on sporadic LOAD might benefit from a sex-specific search for genetic risk factors.

Insulin-like growth factor binding protein-2 interactions with Alzheimer's disease biomarkers.

Plasma levels of insulin-like growth factor binding protein-2 (IGFBP-2) have been associated with Alzheimer's disease (AD) and brain atrophy. Some evidence suggests a potential synergistic effect of IGFBP-2 and AD neuropathology on neurodegeneration, while other evidence suggests the effect of IGFBP-2 on neurodegeneration is independent of AD neuropathology. Therefore, the current study investigated the interaction between plasma IGFBP-2 and cerebrospinal fluid (CSF) biomarkers of AD neuropathology on hippocampal volume and cognitive function. AD Neuroimaging Initiative data were accessed (n=354, 75±7years, 38% female), including plasma IGFBP-2, CSF total tau, CSF Aβ-42, MRI-quantified hippocampal volume, and neuropsychological performances. Mixed effects regression models evaluated the interaction between IGFBP-2 and AD biomarkers on hippocampal volume and neuropsychological performance, adjusting for age, sex, education, APOE ε4 status, and cognitive diagnosis. A baseline interaction between IGFBP-2 and CSF Aβ-42 was observed in relation to left (t(305)=-6.37, p=0.002) and right hippocampal volume (t(305)=-7.74, p=0.001). In both cases, higher IGFBP-2 levels were associated with smaller hippocampal volumes but only among amyloid negative individuals. The observed interaction suggests IGFBP-2 drives neurodegeneration through a separate pathway independent of AD neuropathology.

Hippocampal volume and the course of depressive symptoms over eight years of follow-up.

To estimate the association between hippocampal and total brain volume and the course of depressive symptoms over eight years of follow-up in patients with a history of vascular disease. Within the SMART-Medea study, 636 participants (62 ± 10 years) had a 1.5-tesla brain MRI obtaining hippocampal and total brain volumes. Depressive symptoms were assessed with the Patient Health Questionnaire-9 biannually during eight-year follow-up. Generalized estimating equation models with robust standard errors were used to assess the associations of hippocampal and total brain volumes with depressive symptoms during follow-up adjusting for age, sex, education, and intracranial volume. An interaction term between volume and time (6-month intervals) was included to examine whether the course of depressive symptoms differed according to hippocampal and total brain volume. The mean PHQ-9 score was 2.8 ± 3.5. Smaller hippocampal volumes were associated with an increasing course of depressive symptom levels, while larger volumes were associated with decreasing levels (P-value interaction = 0.07). Smaller total brain volume was associated with consistently higher levels of depressive symptoms, but not with change in course of depressive symptoms (P-value interaction = 0.45). Smaller hippocampal volume but not total brain volume is associated with poorer course of depressive symptoms over eight years of follow-up.

Life-Course Socioeconomic Position and Hippocampal Atrophy in a Prospective Cohort of Older Adults.

Low socioeconomic position (SEP) has been linked to an increased risk of dementia and cognitive decline. However, little is known about the association between SEP and morphologic brain changes in older age. This study examines the relationships between indicators of life-course SEP with both hippocampal volume (HcV) and HcV loss in a population-based cohort of 1328 older adults aged 65 to 80 years. Multivariable linear regression models were used to estimate the associations of SEP with baseline HcV and the annual rate of HcV atrophy according to three life-course conceptual models: the sensitive/critical periods model (which explored SEP in specific periods: in childhood [using parental education], early adulthood [based on participants' education], and midlife [based on participants' socioprofessional group]); the accumulation-of-risk model (life-course cumulative SEP), and the social mobility model (life-course SEP trajectories). Participants with lower midlife SEP had smaller HcV (-0.08 cm; 95% confidence interval, -0.15 to -0.01) and 0.17% (95% confidence interval, 0.04%-0.30%) faster hippocampal atrophy than participants with higher midlife SEP. Childhood and early adulthood SEPs were not related to hippocampal measures. The accumulation-of-risk and the social mobility models revealed that the accumulation of socioeconomic disadvantage and declining socioeconomic trajectories were related to faster hippocampal atrophy. In this cohort of older adults, lower socioprofessional attainment in midlife and disadvantageous life-course socioeconomic position were associated with faster hippocampal atrophy, a cerebral change linked to cognitive disorders. Results support the hypothesized links between socioenvironmental exposures related to stress and/or cognitive enrichment and brain/cognitive reserve capacities.

Reduced DNA methylation of FKBP5 in Cushing's syndrome.

FKBP5 encodes a co-chaperone of HSP90 protein that regulates intracellular glucocorticoid receptor sensitivity. When it is bound to the glucocorticoid receptor complex, cortisol binds with lower affinity to glucocorticoid receptor. Cushing's syndrome is associated with memory deficits, smaller hippocampal volumes, and wide range of cognitive impairments. We aimed at evaluating blood DNA methylation of FKBP5 and its relationship with memory and hippocampal volumes in Cushing's syndrome patients. Polymorphism rs1360780 in FKBP5 has also been assessed to determine whether genetic variations can also govern CpG methylation. Thirty-two Cushing's syndrome patients and 32 matched controls underwent memory tests, 3-Tesla MRI of the brain, and DNA extraction from total leukocytes. DNA samples were bisulfite treated, PCR amplified, and pyrosequenced to assess a total of 41CpG-dinucleotides in the introns 1, 2, 5, and 7 of FKBP5. Significantly lower intronic FKBP5 DNA methylation in CS patients compared to controls was observed in ten CpG-dinucleotides. DNA methylation at these CpGs correlated with left and right HV (Intron-2-Region-2-CpG-3: LHV, r = 0.73, p = 0.02; RHV, r = 0.58, p = 0.03). Cured and active CS patients showed both lower methylation of intron 2 (92.37, 91.8, and 93.34 %, respectively, p = 0.03 for both) and of intron 7 (77.08, 73.74, and 79.71 %, respectively, p = 0.02 and p < 0.01) than controls. Twenty-two subjects had the CC genotype, 34 had the TC genotype, and eight had the TT genotype. Lower average DNA methylation in intron 7 was observed in the TT subjects compared to CC (72.5vs. 79.5 %, p = 0.02) and to TC (72.5 vs. 79.0 %, p = 0.03). Our data demonstrate, for the first time, a reduction of intronic DNA methylation of FKBP5 in CS patients.