Genetic studies of human apolipoproteins. V. A novel rapid procedure to screen apolipoprotein E polymorphism

Search for the elusive haplotype of the APOE polymorphism associated with Alzheimer's disease

The common APOE2/E3/E4 polymorphism is determined by two-site haplotypes: C112R and R158C. Due to strong linkage disequilibrium (LD) between the two sites, three of the four expected haplotypes/alleles (E2, E3, E4) have been observed. Compared to the most common E3 haplotype (C112-R158), E4 (R112-R158) results from a mutation at codon 112, while E2 (C112-C158) results from a mutation at codon 158. The fourth haplotype (E5) having mutations at both sites (R112-C158) has been reported only as an incidental finding in three kindreds. To our knowledge, no systematic search has been done to determine its distribution in the general population. The objective of this study was to search for the elusive haplotype by subcloning a DNA fragment of 177 bp from 355 subjects with the APOE 2/4 genotype followed by sequencing as well as in 11,647 subjects genotyped by TaqMan assays. No example of the E5 haplotype was observed, suggesting it might have a minimum effect, if any, on Alzheimer's disease risk. Under the assumption of strong LD between the two sites, the estimated probability for the occurrence of the E5 haplotype by recombination event is 3.31E-08, which is similar to 5.58E-08 probability obtained by recurrent point mutation.

Lecanemab-Associated Amyloid-β Protofibril in Cerebrospinal Fluid Correlates with Biomarkers of Neurodegeneration in Alzheimer's Disease

OBJECTIVE

The Clarity AD phase III trial showed that lecanemab reduced amyloid markers in early Alzheimer's disease (AD) and resulted in less decline on measures of cognition and function than placebo. Herein, we aimed to characterize amyloid-β (Aβ) protofibril (PF) captured by lecanemab in human cerebrospinal fluid (CSF) from living participants with different stages in AD, which enable an enhanced understanding of the dynamic changes of lecanemab-associated Aβ-PF (Lec-PF) in vivo.

METHODS

We newly developed a unique and highly sensitive immunoassay method using lecanemab that selectively captures Lec-PF. The CSF level of Lec-PF, Aβ42, Aβ40, p-tau181, p-tau 217, total tau, and neurogranin were measured in Japanese participants (n = 163). The participants in this study consisted of 48 cognitively unimpaired Aβ-negative (CU-), 8 cognitively impaired diagnosed as suspected non-Alzheimer's disease pathophysiology, 9 cognitively unimpaired Aβ-positive (CU+), 34 Aβ-positive with mild cognitive impairment (MCI+), and 64 Aβ-positive with AD dementia (AD+).

RESULTS

The CSF Lec-PF levels significantly increased in the groups of MCI+ and AD+ compared with CU- group. Notably, CSF Lec-PF showed modest correlation with plaque-associated biomarkers in Aβ-positive participants and stronger correlation with neurodegeneration biomarkers, such as CSF total tau and neurogranin, suggesting that CSF Lec-PF levels proximally reflect neurodegeneration as well as the amount of senile amyloid plaques.

INTERPRETATION

This is the first report describing Aβ-PF species captured by lecanemab in human CSF and supporting that Lec-PF is correlated with neurodegeneration in AD and may explain the mechanism of the clinical effect of lecanemab. ANN NEUROL 2025;97:993-1006.

Life's Essential 8 and midlife trajectories in cognition and brain health: The CARDIA study

INTRODUCTION

Poor cardiovascular health (CVH) is linked to Alzheimer's disease and dementia; however, its association with neurocognitive trajectories earlier in life remains underexplored.

METHODS

We included 3224 participants with information on CVH at early midlife (mean age 45.0 ± standard deviation 3.4) an cognitive assessments, and neuroimaging 5, 10, and 15 years later including white matter hyperintensities (WMHs), total gray matter (GM), and hippocampal volume. CVH was operationalized according to the American Heart Association's (AHA) "Life's Essential 8" (LE8) guidelines. The association between LE8 and cognitive and neuroimaging measures was examined using mixed linear regression adjusting for age, sex, race, and education.

RESULTS

Worse LE8 score was associated with steeper decline in cognition, higher accumulation of WMHs, and steeper decline in total GM and hippocampal volume.

DISCUSSION

Poor CVH is related to accelerated brain aging across midlife, highlighting the need to screen for and improve CVH earlier to prevent adverse cognitive outcomes.

HIGHLIGHTS

Poor cardiovascular health in early midlife is associated with faster decline in cognition across 10 years overall and in specific domains. Poor and intermediate cardiovascular health was associated with higher accumulation of white matter hyperintensities across midlife. Poor cardiovascular health was associated with faster atrophy in total gray matter volume and hippocampal volume.

Comparison between DSQIID total / sub-item scores and plasma p-tau elevation in adults with Down's syndrome

The Dementia Screening Questionnaire for Individuals with Intellectual Disabilities (DSQIID) is an appropriate screening tool for detecting dementia in Down's syndrome patients. However, whether this questionnaire reflects the neuropsychiatric signs of biomarker-confirmed Alzheimer's disease in DS (DS-AD) remains unknown. To address this issue, we compared the plasma phosphorylated tau (P181tau: p-tau) level of a representative AD biomarker with the total score and each sub-score of the DSQIID. The DSQIID was completed by 43 of the 56 individuals enrolled in the study. The DSQIID total scores tended to be positively associated with age, and some sub-scores increased in an age-dependent manner. DSQIID total scores and some sub-scores were also positively correlated with plasma p-tau levels, while all significant correlations disappeared after adjusting for age. Moreover, one sub-score appeared to have a significant negative correlation with plasma p-tau levels after adjusting for age. The DSQIID likely reflects age-associated behavioral changes in patients with DS. Meanwhile, their scores did not correlate with plasma p-tau after adjusting for age, suggesting that there might be room for improvement in the DSQIID for detecting DS-AD.

Elevated blood pressure is associated with advanced brain aging in mid-life: A 30-year follow-up of The CARDIA Study

BACKGROUND

High blood pressure (BP) is a risk factor for late-life brain health; however, the association of elevated BP with brain health in mid-life is unclear.

METHODS

We identified 661 participants from the Coronary Artery Risk Development in Young Adults Study (age 18-30 at baseline) with 30 years of follow-up and brain magnetic resonance imaging at year 30. Cumulative exposure of BP was estimated by time-weighted averages (TWA). Ideal cardiovascular health was defined as systolic BP < 120 mm Hg, diastolic BP < 80 mm Hg. Brain age was calculated using previously validated high dimensional machine learning pattern analyses.

RESULTS

Every 5 mmHg increment in TWA systolic BP was associated with approximately 1-year greater brain age (95% confidence interval [CI]: 0.50-1.36) Participants with TWA systolic or diastolic BP over the recommended guidelines for ideal cardiovascular health, had on average 3-year greater brain age (95% CI: 1.00-4.67; 95% CI: 1.45-5.13, respectively).

CONCLUSION

Elevated BP from early to mid adulthood, even below clinical cut-offs, is associated with advanced brain aging in mid-life.

Effects of Melissa officinalis Extract Containing Rosmarinic Acid on Cognition in Older Adults Without Dementia: A Randomized Controlled Trial

BACKGROUND

Previous in vitro and in vivo studies on Alzheimer's disease (AD) models have reported that rosmarinic acid (RA) can inhibit the formation of amyloid-β fibrils as well as the oligomerization and deposition of amyloid-β protein. Melissa officinalis (M. officinalis) extract containing 500 mg of RA is tolerable and safe in healthy individuals and patients with mild AD dementia.

OBJECTIVE

This randomized placebo-controlled double-blind trial aimed to assess the effects of M. officinalis extract on cognition in older adults without dementia.

METHODS

This study included individuals who were diagnosed with subjective or mild cognitive impairment (n = 323). The trial involved M. officinalis extract supplementation (500 mg of RA per day) period of 96 weeks followed by a washout period of 24 weeks. The primary endpoint was the Alzheimer's Disease Assessment Scale-cognitive subscale score, and the secondary endpoints were other cognitive measure results as well as safety and tolerability.

RESULTS

There were no significant differences in cognitive measures between the placebo and M. officinalis groups from baseline to 96 weeks. However, based on the analysis of Clinical Dementia Rating Sum of Boxes scores in participants without hypertension, the score was found to be increased by 0.006 and decreased by 0.085 in the M. officinalis and placebo groups, respectively; this difference was statistically significant (p = 0.036). Furthermore, there were no differences in vital signs, physical and neurological measures, or hippocampal volume between the two groups.

CONCLUSION

These results indicate that M. officinalis extract may help prevent cognitive decline in older adults without hypertension.

Race, sex, and mid-life changes in brain health: Cardia MRI substudy

OBJECTIVE

To examine longitudinal race and sex differences in mid-life brain health and to evaluate whether cardiovascular health (CVH) or apolipoprotein E (APOE) ε4 explain differences.

METHODS

The study included 478 Black and White participants (mean age: 50 years). Total (TBV), gray (GMV), white (WMV), and white matter hyperintensity (WMH) volumes and GM-cerebral blood flow (CBF) were acquired with 3T-magnetic resonance imaging at baseline and 5-year follow-up. Analyses were based on general linear models.

RESULTS

There were race x sex interactions for GMV (P-interaction = .004) and CBF (P-interaction = .01) such that men showed more decline than women, and this was most evident in Blacks. Blacks compared to Whites had a significantly greater increase in WMH (P = .002). All sex-race differences in change were marginally attenuated by CVH and APOE ε4.

CONCLUSION

Race-sex differences in brain health emerge by mid-life. Identifying new environmental factors beyond CVH is needed to develop early interventions to maintain brain health.

Association of the prefrailty with global brain atrophy and white matter lesions among cognitively unimpaired older adults: the Nakajima study

Physical frailty has been associated with adverse outcomes such as dementia. However, the underlying structural brain abnormalities of physical frailty are unclear. We investigated the relationship between physical frailty and structural brain abnormalities in 670 cognitively unimpaired individuals (mean age 70.1 years). Total brain volume (TBV), hippocampal volume (HV), total white matter hypointensities volume (WMHV), and estimated total intracranial volume (eTIV) on the 3D T1-weighted images were automatically computed using FreeSurfer software. Participants were divided into two states of physical frailty (robust vs. prefrail) based on the revised Japanese version of the Cardiovascular Health Study criteria. The multivariable-adjusted mean values of the TBV-to-eTIV ratio was significantly decreased, whereas that of the WMHV-to-eTIV ratio was significantly increased in the prefrail group compared with the robust group. Slowness, one of the components of physical frailty, was significantly associated with reduced TBV-to-eTIV and HV-to-eTIV ratios, and slowness and weakness were significantly associated with an increased WMHV-to-eTIV ratio. Our results suggest that the prefrail state is significantly associated with global brain atrophy and white matter hypointensities. Furthermore, slowness was significantly associated with hippocampal atrophy.

Twenty-Five-Year Change in Cardiac Structure and Function and Midlife Cognition: The CARDIA Study

BACKGROUND AND OBJECTIVE

The goal of this work was to determine whether midlife cardiac structure and function and their 25-year change from early to middle adulthood are associated with lower midlife cognition.

METHODS

We studied 2,653 participants from the Coronary Artery Risk Development in Young Adults (CARDIA) study (57% women, 46% Black). Echocardiograms were obtained at year 5, 25, and 30 visits (participant mean age 30, 50, and 55 years) to assess left ventricular (LV) mass (LVM), LV systolic function with LV ejection fraction (LVEF), and LV diastolic function with left atrial volume (LAV) and early peak mitral velocity (E)/early peak mitral annular velocity (e') ratio. LVM and LAV were indexed to body surface area (LVMi and LAVi). At year 30, 5 cognitive domains were measured: global cognition, processing speed, executive function, delayed verbal memory, and verbal fluency. We investigated the association between midlife (year 30) and 25-year change in cardiac structure and function on midlife cognition using linear regressions.

RESULTS

Over 25 years, LVMi and LAVi increased with mean change (SD) per year of 0.27 (0.28) g/m² and 0.42 (0.15) mL/m², while LVEF decreased by 0.11% (0.02%). After adjustment for demographics and education, 25-year increase (≥1 SD) in LVMi was associated with lower cognition on most tests (p ≤ 0.02); 25-year increase in LAVi was associated with lower global cognition (p = 0.04), but 25-year decrease in LVEF was not associated with cognition. Further adjustment for cardiovascular risk factors led to similar results. In addition, unlike year 30 E/e' ratio and LVEF, higher year 30 LVMi and LAVi were significantly associated with worse cognition on most cognitive tests.

DISCUSSION

Midlife cardiac structure and its change from early to middle adulthood are associated with lower midlife cognition even after accounting for confounders. Unlike systolic function, midlife LV diastolic function and its 25-year change were also linked to cognition. Our results provide information linking early to midlife cardiac structure and function to cognition.

Safety and efficacy of Melissa officinalis extract containing rosmarinic acid in the prevention of Alzheimer's disease progression

We conducted a randomized placebo-controlled double-blind 24-week trial using Melissa officinalis (M. officinalis) extract richly containing rosmarinic acid (RA) on patients with mild dementia due to Alzheimer's disease (AD) with the aim to examine the safety and tolerability (primary endpoint) of RA (500 mg daily) and its clinical effects and disease-related biomarker changes (secondary endpoints). Patients (n = 23) diagnosed with mild dementia due to probable AD were randomized to either the placebo or M. officinalis extract group. No differences in vital signs or physical and neurologic examination results were detected between the M. officinalis and placebo groups. No serious adverse events occurred. There were no significant differences in cognitive measures; however, the mean Neuropsychiatric Inventory Questionnaire (NPI-Q) score improved by 0.5 points in the M. officinalis group and worsened by 0.7 points in the placebo group between the baseline and 24-week visit, indicating a significant difference (P = 0.012). No significant differences were apparent in disease-related biomarkers between the groups. M. officinalis extract containing 500 mg of RA taken daily was safe and well-tolerated by patients with mild dementia due to AD. Our results suggest that RA may help prevent the worsening of AD-related neuropsychiatric symptoms.Trial registration: The registration number for this clinical trial is UMIN000007734 (16/04/2012).

Cardiovascular risk factors and accelerated cognitive decline in midlife: The CARDIA Study

OBJECTIVE

Increasing evidence supports an association between midlife cardiovascular risk factors (CVRFs) and risk of dementia, but less is known about whether CVRFs influence cognition in midlife. We examined the relationship between CVRFs and midlife cognitive decline.

METHODS

In 2,675 black and white middle-aged adults (mean age 50.2 ± 3.6 years, 57% female, 45% black), we measured CVRFs at baseline: hypertension (31%), diabetes mellitus (11%), obesity (43%), high cholesterol (9%), and current cigarette smoking (15%). We administered cognitive tests of memory, executive function, and processing speed at baseline and 5 years later. Using logistic regression, we estimated the association of CVRFs with accelerated cognitive decline (race-specific decline ≥1.5 SD from the mean change) on a composite cognitive score.

RESULTS

Five percent (n = 143) of participants had accelerated cognitive decline over 5 years. Smoking, hypertension, and diabetes mellitus were associated with an increased likelihood of accelerated decline after multivariable adjustment (adjusted odds ratio [AOR] 1.65, 95% confidence interval [CI] 1.00-2.71; AOR 1.87, 95% CI 1.26-2.75; AOR 2.45, 95% CI 1.54-3.88, respectively), while obesity and high cholesterol were not associated with risk of decline. These results were similar when stratified by race. The likelihood of accelerated decline also increased with greater number of CVRFs (1-2 CVRFs: AOR 1.77, 95% CI 1.02-3.05; ≥3 CVRFs: AOR 2.94, 95% CI 1.64-5.28) and with Framingham Coronary Heart Disease Risk Score ≥10 (AOR 2.29, 95% CI 1.21-4.34).

CONCLUSIONS

Midlife CVRFs, especially hypertension, diabetes mellitus, and smoking, are common and associated with accelerated cognitive decline at midlife. These results identify potential modifiable targets to prevent midlife cognitive decline and highlight the need for a life course approach to cognitive function and aging.

Type 2 diabetes and later cognitive function in older American Indians: The Strong Heart Study

OBJECTIVES

Insulin resistance is a substantial health issue for American Indians, with type 2 diabetes overrepresented in this population as compared with non-Hispanic whites. Insulin resistance and its related conditions in turn increase risk for dementia and cognitive impairment. The aim of the current study was to determine whether type 2 diabetes and insulin resistance at midlife was associated with later-life cognitive testing in a large sample of older American Indians, aged 65 and older.

METHODS

American Indian participants who underwent both fasting blood draw as part of the Strong Heart Study and had subsequent cognitive testing as part of the later adjunct Cerebrovascular Disease and its Consequences in American Indians study were included (n = 790). Regression models examined type 2 diabetes and impaired fasting glucose and subsequent cognitive test performance as part of a longitudinal study design. The relationship between a continuous measure of insulin resistance and later cognitive test performance was assessed using generalized estimating equations.

RESULTS

Controlling for demographic and clinical factors, verbal fluency and processing speed/working memory were significantly negatively associated with having type 2 diabetes and with insulin resistance, but not with impaired fasting glucose.

CONCLUSION

In this sample of American Indians, type 2 diabetes at midlife was associated with subsequent lower performance on measures of executive function. These results may have important implications for future implementation of diagnostic and intervention services in this population.

Dietary patterns during adulthood and cognitive performance in midlife: The CARDIA study

OBJECTIVE

To investigate whether dietary patterns (Mediterranean diet [MedDiet], Dietary Approaches to Stop Hypertension [DASH], and A Priori Diet Quality Score [APDQS]) during adulthood are associated with midlife cognitive performance.

METHODS

We studied 2,621 Coronary Artery Risk Development in Young Adults (CARDIA) participants; 45% were black, 57% were female, and mean age was 25 ± 3.5 years at baseline (year 0). Mean diet scores were calculated from diet history at baseline, year 7, and year 20 (mean age 25, 32, and 45 years, respectively). Cognitive function was assessed at years 25 and 30 (mean age 50 and 55 years, respectively). Linear models were used to examine association between tertiles of diet score and change in composite cognitive function and cognitive z scores (verbal memory [Rey Auditory Verbal Learning Test], processing speed [Digit Symbol Substitution Test], and executive function [Stroop Interference test]) and the Montreal Cognitive Assessment (MoCA) at year 30.

RESULTS

DASH was not associated with change in cognitive performance. Higher MedDiet and APDQS scores were associated with less decline in cognitive function (MedDiet: low -0.04, middle 0.03, high 0.03, p = 0.03; APDQS: low -0.04, middle -0.00, high 0.06, p < 0.01) and Stroop Interference (MedDiet: low 0.09, middle -0.06, high -0.03; APDQS: low 0.10, middle 0.01, high -0.09, both p < 0.01). Odds ratios (95% confidence interval) for poor global cognitive function (≥1 SD below mean MoCA score) comparing extreme tertiles of diet scores were 0.54 (0.39-0.74) for MedDiet, 0.48 (0.33-0.69) for APDQS, and 0.89 (0.68-1.17) for DASH.

CONCLUSION

Greater adherence to MedDiet and APDQS dietary patterns during adulthood was associated with better midlife cognitive performance. Additional studies are needed to define the combination of foods and nutrients for optimal brain health across the life course.

Visit-to-Visit Blood Pressure Variability in Young Adulthood and Hippocampal Volume and Integrity at Middle Age: The CARDIA Study (Coronary Artery Risk Development in Young Adults)

The aims of this study are to assess the relationships of visit-to-visit blood pressure (BP) variability in young adulthood to hippocampal volume and integrity at middle age. We used data over 8 examinations spanning 25 years collected in the CARDIA study (Coronary Artery Risk Development in Young Adults) of black and white adults (age, 18-30 years) started in 1985 to 1986. Visit-to-visit BP variability was defined as by SDBP and average real variability (ARVBP, defined as the absolute differences of BP between successive BP measurements). Hippocampal tissue volume standardized by intracranial volume (%) and integrity assessed by fractional anisotropy were measured by 3-Tesla magnetic resonance imaging at the year-25 examination (n=545; mean age, 51 years; 54% women and 34% African Americans). Mean systolic BP (SBP)/diastolic BP levels were 110/69 mm Hg at year 0 (baseline), 117/73 mm Hg at year 25, and ARVSBP and SDSBP were 7.7 and 7.9 mm Hg, respectively. In multivariable-adjusted linear models, higher ARVSBP was associated with lower hippocampal volume (unstandardized regression coefficient [standard error] with 1-SD higher ARVSBP: -0.006 [0.003]), and higher SDSBP with lower hippocampal fractional anisotropy (-0.02 [0.01]; all P<0.05), independent of cumulative exposure to SBP during follow-up. Conversely, cumulative exposure to SBP and diastolic BP was not associated with hippocampal volume. There was no interaction by sex or race between ARVSBP or SDSBP with hippocampal volume or integrity. In conclusion, visit-to-visit BP variability during young adulthood may be useful in assessing the potential risk for reductions in hippocampal volume and integrity in midlife.

Left Ventricular Mass, Brain Magnetic Resonance Imaging, and Cognitive Performance: Results From the Strong Heart Study

Left ventricular mass (LVM) has been shown to serve as a measure of target organ damage resulting from chronic exposure to several risk factors. Data on the association of midlife LVM with later cognitive performance are sparse. We studied 721 adults (mean age 56 years at baseline) enrolled in the Strong Heart Study (SHS, 1993-1995) and the ancillary CDCAI (Cerebrovascular Disease and Its Consequences in American Indians) Study (2010-2013), a study population with high prevalence of cardiovascular disease. LVM was assessed with transthoracic echocardiography at baseline in 1993 to 1995. Cranial magnetic resonance imaging and cognitive testing were undertaken between 2010 and 2013. Generalized estimating equations were used to model associations between LVM and later imaging and cognition outcomes. The mean follow-up period was 17 years. A difference of 25 g in higher LVM was associated with marginally lower hippocampal volume (0.01%; 95% confidence interval, 0.02-0.00; P=0.001) and higher white matter grade (0.10; 95% confidence interval, 0.02-0.18; P=0.014). Functionally, participants with higher LVM tended to have slightly lower scores on the modified mini-mental state examination (0.58; 95% confidence interval, 1.08-0.08; P=0.024). The main results persisted after adjusting for blood pressure levels or vascular disease. The small overall effect sizes are partly explained by survival bias because of the high prevalence of cardiovascular disease in our population. Our findings emphasize the role of cardiovascular health in midlife as a target for the prevention of deleterious cognitive and functional outcomes in later life.

Cognitive decline and the PPAR-γ Pro12Ala genotype: variation by sex and ethnicity

Objective

We investigated the association between the peroxisome proliferator-activated receptor (PPAR)-gamma Pro12Ala polymorphism and cognitive decline in older adults.

Methods

Participants from a population-based cohort of older Hispanic and non-Hispanic white adults (n = 492) were administered the Mini Mental State Examination (MMSE), a multi-domain cognitive screening tool, and the Behavioral Dyscontrol Scale (BDS), a measure of executive cognitive function, at baseline and at follow-up, an average of 22 months later. Multiple linear regression was used to investigate the association between the two cognitive test scores and the Pro12Ala polymorphism.

Results

At baseline, presence of the Ala12 allele was not significantly associated with MMSE score (P = 0.62) nor with BDS score (P = 0.85). Heterogeneity was present for cognitive decline as measured by the MMSE among ethnic, sex and Ala12 allele status (P = 0.04 for three-way interaction term). Stratification by the cross-classification of sex and ethnicity revealed significantly greater declines in MMSE score among male Hispanic carriers of the Ala12 allele compared to male Hispanic non-carriers (decline = 4.0 versus 1.6 points; P = 0.02). A significant difference in decline between Ala12 carriers and non-carriers was not present among the other sex/ethnic groups.

Conclusions

Carriers of the PPAR-γ Ala12 allele showed greater cognitive decline compared to non-carriers as detected by the MMSE but the risk varied across sex and ethnic groups. Male Ala12 carriers of Hispanic origin may be a high-risk group for cognitive decline.

Cognitive function in a middle aged cohort is related to higher quality dietary pattern 5 and 25 years earlier: the CARDIA study

BACKGROUND

Preserving cognitive function is an important public health issue. We investigated whether dietary pattern associates with cognitive function in middle-age.

METHODS

We studied 2435 participants in the community-based Coronary Artery Risk Development in Young Adults (CARDIA) study of black and white men and women aged 18-30 in 1985-86 (year 0, Y0). We hypothesized that a higher A Priori Diet Quality Score, measured at Y0 and Y20, is associated with better cognitive function measured at Y25. The diet score incorporated 46 food groups (each in servings/day) as the sum of quintile ranks of food groups rated beneficial, 0 for food groups rated neutral, and reversed quintile ranks for food groups rated adverse; higher score indicated better diet quality. Y25 cognitive testing included verbal memory (Rey Auditory-Verbal Learning Test (RAVLT)), psychomotor speed (Digit Symbol Substitution Test (DSST)) and executive function (Stroop).

RESULTS

Per 10-unit higher diet score at Y20, the RAVLT was 0.32 words recalled higher, the DSST was 1.76 digits higher, and the Stroop was 1.00 seconds+errors lower (better performance) after adjusting for race, sex, age, clinic, and energy intake. Further adjustment for physical activity, smoking, education, and body mass index attenuated the association slightly. Diet score at Y0 and increase in diet score over 20 years were also positively associated with each cognitive test.

CONCLUSIONS

A higher quality dietary pattern was associated with better cognitive function 5 years and even 25 years later in apparently healthy middle-aged adults.

Consumption of green tea, but not black tea or coffee, is associated with reduced risk of cognitive decline

Our objective was to determine whether the consumption of green tea, coffee, or black tea influences the incidence of dementia and mild cognitive impairment (MCI) in older people. We conducted a population-based prospective study with Japanese residents aged >60 years from Nakajima, Japan (the Nakajima Project). Participants received an evaluation of cognitive function and blood tests. The consumption of green tea, coffee, and black tea was also evaluated at baseline. Of 723 participants with normal cognitive function at a baseline survey (2007–2008), 490 completed the follow up survey in 2011–2013. The incidence of dementia during the follow-up period (mean ± SD: 4.9±0.9 years) was 5.3%, and that of MCI was 13.1%. The multiple-adjusted odds ratio for the incidence of overall cognitive decline (dementia or MCI) was 0.32 (95% CI: 0.16–0.64) among individuals who consumed green tea every day and 0.47 (95% CI: 0.25–0.86) among those who consumed green tea 1–6 days per week compared with individuals who did not consume green tea at all. The multiple-adjusted odds ratio for the incidence of dementia was 0.26 (95% CI: 0.06–1.06) among individuals who consumed green tea every day compared with those who did not consume green tea at all. No association was found between coffee or black tea consumption and the incidence of dementia or MCI. Our results indicate that green tea consumption is significantly associated with reduced risk of cognitive decline, even after adjustment for possible confounding factors.

Change in inflammatory markers and cognitive status in the oldest-old women from the Study of Osteoporotic Fractures

OBJECTIVES

To determine the association between interleukin-6 (IL-6), IL-6 soluble receptor (sR), and soluble tumor necrosis factor receptor-1 (sTNF-R1) and cognitive status in the oldest-old women.

DESIGN

Twenty-year longitudinal cohort study.

SETTING

Four clinical sites in the United States.

PARTICIPANTS

Women from the Study of Osteoporotic Fractures (N = 905; mean age 88.3 ± 2.8 at cognitive status adjudication).

MEASUREMENTS

At Year 20, cognitive status was adjudicated as normal, mild cognitive impairment (MCI), or dementia. Inflammatory markers were measured from blood serum at Years 10 and 16 in a random sample of women.

RESULTS

Over 10 years, 199 (22.0%) women developed MCI and 145 (16.0%) dementia. There were no significant associations between IL-6 or sTNF-R1 and cognitive status. High IL-6-sR (≥ 37,401.36 pg/mL, highest tertile) at Year 16 was significantly associated with lower risk of dementia (odds ratio (OR) = 0.54, 95% confidence interval (CI) = 0.30-0.97) than in women with lower levels (<37,401.36 pg/mL, lower two tertiles). Women with high IL-6-sR at both time points (OR = 0.39, 95% CI = 0.17-0.89) or who transitioned to a high level (OR = 0.35, 95% CI = 0.14-0.88) had a lower risk of dementia.

CONCLUSION

In this cohort of white, high-functioning oldest-old women, a consistently high or an increasing level of IL-6-sR was associated with lower risk of dementia. Compared with other studies of younger-old adults, this suggests that the effect of inflammation on dementia may differ in younger-old and the oldest-old individuals. Understanding these differences will be crucial in interpreting results from ongoing clinical trials and in targeting therapeutic strategies to the oldest-old individuals.

Delayed postprandial metabolism of triglyceride-rich lipoproteins in obese young men compared to lean young men

BACKGROUND

Obesity, especially visceral obesity, has been known to affect lipoprotein metabolism, but it is not clear whether obesity in young, apparently healthy men is associated with postprandial triglyceride-rich lipoprotein (TRL) metabolism.

METHODS

Ten young normolipidemic, normoglycemic obese men (20.6 ± 0.5 y, BMI 27.5 ± 1.0 kg/m(2)) and 11 lean healthy men (22.1 ± 0.4 y, 21.2 ± 0.4 kg/m(2)) ingested OFTT cream (1g/kg body weight). Fasting and postprandial blood samples were obtained for up to 6h, and serum lipids and lipoproteins were analyzed.

RESULTS

The obese men with a fasting triglyceride (TG) in the normal range and not different from the fasting value of lean controls had a prolonged postprandial response, indicated by a significantly greater incremental areas under the curve in serum TG, TRL-TG, and remnant-like particle-cholesterol (RLP-C) compared with controls. Plasma glucose levels did not change during the test. Differences in serum insulin levels and homeostasis model assessment-insulin resistance (HOMA-IR) were not statistically significant between the two groups; however, trends toward higher levels were shown in obese young men.

CONCLUSIONS

The obese young men showed significantly delayed TRL metabolism compared to the lean young men after fat loading, even though the obese men were normolipidemic. These results suggest the possibility that early insulin resistance in the obese young men may have caused the decrease of lipoprotein lipase activity and induced delayed TRL metabolism. A fat loading test without carbohydrate may provide a useful tool for the detection of delayed postprandial TRL metabolism and early insulin resistance.

High-molecular-weight beta-amyloid oligomers are elevated in cerebrospinal fluid of Alzheimer patients

There is accumulating evidence that soluble amyloid-beta (Abeta) oligomers, rather than amyloid fibrils, are the principal pathogenic species in Alzheimer disease (AD). Here, we have developed a novel enzyme-linked immunosorbent assay (ELISA) specific for high-molecular-weight (HMW) Abeta oligomers. Analysis of Abeta oligomers derived from synthetic Abeta 1-42, by size-exclusion chromatography (SEC), revealed that our ELISA specifically detected HMW Abeta oligomers of 40-200 kDa. Using this ELISA, we detected significantly higher (P<0.0001) signals in cerebrospinal fluid (CSF) samples from 25 patients with AD or mild cognitive impairment (MCI), compared to 25 age-matched controls. As a test for discriminating between the AD/MCI and control groups, the area under the curve in receiver operating characteristic analysis for the CSF HMW Abeta oligomers was greater than that for CSF Abeta x-42. Furthermore, the CSF levels of HMW Abeta oligomers showed a negative correlation with Mini-Mental State Examination scores in the AD/MCI group. We conclude that the CSF HMW Abeta oligomers detected by our ELISA could be useful as a diagnostic marker for AD, and also as a potential surrogate marker for disease severity. Our results support the idea that soluble HMW Abeta oligomers play a critical role in the pathogenesis and progression of AD.

APOE distribution in world populations with new data from India and the UK

BACKGROUND

The APOE gene and its protein product is associated with a number of plasma proteins like very-low density lipoprotein (VLDL), high density lipoprotein (HDL) chylomicrons, chylomicron remnants, and plays a crucial role in lipid metabolism. The APOE gene is polymorphic and common alleles (*E2, *E3 and *E4) have been associated with a number of common and complex diseases in different populations. Due to their crucial role in metabolism and clinical significance, it is imperative that allelic variation in different populations is analysed to evaluate the usage of APOE in an evolutionary and clinical context.

AIM

We report allelic variation at the APOE locus in three European and four Indian populations and evaluate global patterns of genetic variation at this locus. The large, intricate and unexpected heterogeneity of this locus in its global perspective may have insightful consequences, which we have explored in this paper.

SUBJECT AND METHODS

Apolipoprotein E genotypes were determined in four population groups (Punjabi Sikhs, Punjabi Hindus, Maria Gonds and Koch, total individuals = 497) of India and three regionally sub-divided British populations (Nottinghamshire, East Midlands and West Midlands, total individuals = 621). The extent and distribution of APOE allele frequencies were compared with 292 populations of the world using a variety of multivariate methods.

RESULTS

Three alleles, APOE*E2, APOE*E3 and APOE*E4, were observed with contrasting variation, although *E4 was absent in the tribal population of Koch. Higher heterozygosities (>43%) in British populations reflected their greater genetic diversity at this locus. The overall pattern of allelic diversity among these populations is comparable to many European and Indian populations. At a global level, higher frequencies of the *E2 allele were observed in Africa and Oceania (0.099 +/- 0.083 and 0.111 +/- 0.052, respectively). Similarly, *E4 allele averages were higher in Oceania (0.221 +/- 0.149) and Africa (0.209 +/- 0.090), while Indian and Asian populations showed the highest frequencies of *E3 allele. The coefficient of gene differentiation was found to be highest in South America (9.6%), although the highest genetic diversity was observed in Oceania (48.7%) and Africa (46.3%). APOE*E2 revealed a statistically significant decreasing cline towards the north in Asia (r = -0.407, d.f. = 70, p < 0.05), which is not compatible with the coronary heart disease statistics in this continent. APOE*E4 showed a significant increasing cline in North European populations. Spatial autocorrelation analysis shows that the variation at this locus is influenced by 'isolation by distance' with a strong positive correlation for lower distances up to 1313 km.

CONCLUSION

Overall APOE allelic variation in UK and Indian populations is comparable to previous studies but in tribal populations *E4 allele frequency was very low or absent. At a global level allelic variation shows that geography, isolation by distance, genetic drift and possibly pre-historical selection are responsible for shaping the spectrum of genetic variation at the APOE gene. Overall, APOE is a good anthropogenetic and clinical diagnostic marker.

Sex-specific interaction between APOE genotype and carbohydrate intake affects plasma HDL-C levels: the Strong Heart Family Study

Low plasma levels of high-density lipoprotein cholesterol (HDL-C) are identified as a risk factor for cardiovascular disease (CVD). Sexual dimorphism, however, is widely reported in both HDL-C and CVD, with the underlying explanations of these sexual differences not fully understood. HDL-C is a complex trait influenced by both genes and dietary factors. Here we examine evidence for a sex-specific effect of APOE and the macronutrient carbohydrate on HDL-C, triglycerides (TG) and apoprotein A-1 (ApoA-1) in a sample of 326 male and 423 female participants of the Strong Heart Family Study (SHFS). Using general estimating equations in SAS to account for kinship correlations, stratifying by sex, and adjusting for age, body mass index (BMI) and SHS center, we examine the relationship between APOE genotype and carbohydrate intake on circulating levels of HDL-C, TG, and ApoA-1 through a series of carbohydrate-by-sex interactions and stratified analyses. APOE-by-carbohydrate intake shows significant sex-specific effects. All males had similar decreases in HDL-C levels associated with increased carbohydrate intake. However, only those females with APOE-4 alleles showed significantly lower HDL-C levels as their percent of carbohydrate intake increased, while no association was noted between carbohydrate intake and HDL-C in those females without an APOE-4 allele. These findings demonstrate the importance of understanding sex differences in gene-by-nutrient interaction when examining the complex architecture of HDL-C variation.

Influence of aging and menopause on postprandial lipoprotein responses in healthy adult women

AIM

To analyze the influence of menopause and age on postprandial lipoprotein responses in healthy adult women.

METHOD

Twenty-seven healthy young and middle-aged pre- and postmenopausal female volunteers aged 21-53 y were enrolled. They ingested OFTT cream(Jomo, Takasaki, Japan). Fasting and postprandial blood samples were obtained for up to 6 h, and serum concentrations of lipoproteins were analyzed.

RESULTS

In the postprandial phase, serum triglycerides(TG), remnant-like particle(RLP)-TG(RLP-TG), RLP-cholesterol(RLP-C), and TG-rich lipoprotein-TG(TRL-TG)concentrations in all groups peaked after 2 h. After 4 h, the TG, RLP-C, RLP-TG and TRL-TG concentrations in the young women returned to the fasting concentrations. However, at 6 h, these parameters in the pre- and postmenopausal women had barely returned to the fasting concentrations.

CONCLUSION

The present results suggest that:(1)the magnitude of postprandial TG concentrations is dependent on age, but not on menopause;(2)clearance of remnant lipoproteins is delayed with age in pre- and postmenopausal women compared to young women, and(3)menopause is associated with an increase of RLP-C, but may not influence LDL particle size.

Do long-term HDL-C declines associated with a first birth vary by apo E phenotype? The Coronary Artery Risk Development in Young Adults (CARDIA) study

BACKGROUND

High-density lipoprotein cholesterol (HDL-C) levels in premenopausal and postmenopausal women are differentially affected by exogenous sex hormones depending on their apolipoprotein E (apo E) genotype. Because endogenous sex hormones markedly increase during pregnancy, we examined whether HDL-C declines after a first birth varied by apo E polymorphisms.

METHODS

In 1147 nulliparas (416 black, 731 white), fasting blood samples (nonpregnant) were drawn at baseline and at follow-up years 5, 7, and 10. Time-dependent pregnancy groups included 0 pregnancies (P0), 1+ short pregnancy (P1+), 1 birth (B1), 2 or more births (B2+). ApoE groups by alleles identified with a phenotype method included E4 (4/3 and 4/4), E3 (3/3), and E2 (2/2 and 3/2). Differences in adjusted mean HDL-C changes among pregnancy groups and ApoE groups were examined using repeated measures multiple linear regression.

RESULTS

HDL-C declines associated with parity (one or more births) depended on ApoE group (ApoE*Pregnancy Interaction; p < 0.002). For B1 and B2+ vs. P0, HDL-C declines were -2.4 to -2.7 mg/dl in E4 and -3.4 to -4.1 mg/dl in E3. In E2, HDL-C declines were -6.6 mg/dl for one birth, and -11.5 mg/dl for two or more births, each relative to the 0 pregnancies (P0) group (linear trend, p < 0.001).

CONCLUSIONS

The degree to which childbearing adversely affects long-term HDL-C declines varies by apo E phenotype, based on a method that accurately classifies genotype. Our findings show that 2/2 and 3/2 genotypes are associated with larger parity-related HDL-C declines than 3/3, 4/3, and 4/4 genotypes.

Decreased beta-amyloid peptide42 in cerebrospinal fluid of patients with progressive supranuclear palsy and corticobasal degeneration

Several previous studies have identified biochemical markers for Alzheimer's disease (AD): cerebrospinal fluid (CSF)-beta-amyloid peptide42 (CSF-Abeta42), CSF-total tau protein (CSF-tau) and CSF-phosphorylated tau protein (CSF-ptau). Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) as well as AD are diseases with tauopathies. CSF-Abeta42, CSF-tau, and CSF-ptau have not been rigorously investigated in PSP and CBD. In the present study, we assessed CSF-Abeta42, CSF-tau, and CSF-ptau as biochemical markers for PSP and CBD, compared with AD. The subjects consisted of 18 cases of PSP, 9 cases with CBD, 69 cases with AD, and 43 control subjects. Genotyping or phenotyping of apolipoprotein E (apoE) was also performed. CSF-Abeta42 levels were significantly decreased in patients with PSP and CBD as well as in AD patients. The ratio of CSF-ptau to CSF-Abeta42 provided high diagnostic accuracy to distinguish both PSP from AD, and CBD from AD. ApoE genotype/phenotype was not associated with CSF-Abeta42 levels in all groups. We concluded that CSF-Abeta42 levels are reduced in PSP and CBD as well as in AD.

Linkage analysis of LDL cholesterol in American Indian populations: the Strong Heart Family Study

Previous studies have demonstrated that low density lipoprotein cholesterol (LDL-C) concentration is influenced by both genes and environment. Although rare genetic variants associated with Mendelian causes of increased LDL-C are known, only one common genetic variant has been identified, the apolipoprotein E gene (APOE). In an attempt to localize quantitative trait loci (QTLs) influencing LDL-C, we conducted a genome-wide linkage scan of LDL-C in participants of the Strong Heart Family Study (SHFS). Nine hundred eighty men and women, age 18 years or older, in 32 extended families at three centers (in Arizona, Oklahoma, and North and South Dakota) were phenotyped for LDL-C concentration and other risk factors. Using a variance component approach and the program SOLAR, and after accounting for the effects of covariates, we detected a QTL influencing LDL-C on chromosome 19, nearest marker D19S888 at 19q13.41 [logarithm of odds (LOD) = 4.3] in the sample from the Dakotas. This region on chromosome 19 includes many possible candidate genes, including the APOE/C1/C4/C2 gene cluster. In follow-up association analyses, no significant evidence for an association was detected with the APOE*2 and APOE*4 alleles (P = 0.76 and P = 0.53, respectively). Suggestive evidence of linkage to LDL-C was detected on chromosomes 3q, 4q, 7p, 9q, 10p, 14q, and 17q. These linkage signals overlap positive findings for lipid-related traits and harbor plausible candidate genes for LDL-C.

Apolipoprotein E phenotype affects the malondialdehyde-modified LDL concentration and forearm endothelial function in postmenopausal women

OBJECTIVE

We investigated whether the apolipoprotein E (apo E) phenotype affects the serum concentration of malondialdehyde-modified low-density lipoprotein (MDA-LDL) or forearm endothelial function in postmenopausal women.

PATIENTS AND MEASUREMENTS

Individuals were divided into three groups according to their apo E phenotype: E2 (E2/2 and E2/3, n = 12); E3 (E3/3, n = 71); and E4 (E3/4 and E4/4, n = 27). The serum concentrations of lipids and MDA-LDL were measured. Forearm blood flow during reactive hyperaemia and after sublingual nitroglycerin administration was measured by strain-gauge plethysmography.

RESULTS

The serum concentrations of total and LDL cholesterol were significantly higher in the E4 group than in the E2 group (P < 0.05) or in the E3 group (P < 0.05). The serum apo B concentration was significantly higher in the E4 group than in the E2 group (P < 0.05). The serum concentrations of high density lipoprotein (HDL) cholesterol and nitrite/nitrate were significantly lower in the E4 group than in the E2 group (P < 0.05). Other lipid concentrations did not differ in the three groups. The serum MDA-LDL concentration was highest in the E4 group, and was lowest in the E2 group (E2: 91.1 +/- 6.9 IU/l, E3: 112.3 +/- 5.9 IU/l, E4: 128.8 +/- 9.9 IU/l; P < 0.05). The forearm blood flow response to reactive hyperaemia was lowest in the E4 group, and highest in the E2 group (E2: 52.2 +/- 5.8 ml/min per 100 ml tissue, E3: 40.7 +/- 1.7 ml/min per 100 ml tissue, E4: 33.4 +/- 2.4 ml/min per 100 ml tissue; P < 0.05). The forearm blood flow changes in response to nitroglycerine were similar between all three groups.

CONCLUSIONS

The apo E phenotype affects the serum MDA-LDL concentration and forearm endothelial function in postmenopausal women.

Heritability of C-reactive protein and association with apolipoprotein E genotypes in Japanese Americans

Numerous studies have demonstrated that increased C-reactive protein (CRP) levels predict coronary heart disease, stroke, peripheral vascular disease, and diabetes, and are associated with features of the metabolic syndrome. Only three previous studies have investigated the heritability of CRP levels, primarily in samples of Caucasian families. The purpose of the present study was to estimate the magnitude of genetic influences on CRP levels, and to examine potential associations between variation in the APOE gene and CRP levels, using a sample of 562 individual Japanese Americans from 68 extended kindreds. In general, correlation coefficients between first-degree relatives for CRP were approximately 0.2, and spouse correlations did not differ from zero, consistent with genetic influences. Heritability estimates were approximately 0.3 (p < 0.01), even with adjustment for factors known to influence CRP levels. A significant relationship was seen between unadjusted CRP levels and APOE genotypes (p = 0.02), with the highest mean CRP level among epsilon2 carriers (1.20 mg/L), and nearly the same mean levels among epsilon3/epsilon3 subjects and epsilon4 carriers (0.72 and 0.74 mg/L, respectively). However, this relationship was diminished with adjustment for covariates (p = 0.07). These results demonstrate the presence of both genetic and environmental effects on CRP levels among Asian Americans, and additional studies are needed to determine if the APOE gene contributes to these genetic influences.

Population genetics of apolipoproteins A-IV, E, and H, and the angiotensin converting enzyme (ACE): associations with lipids, and apolipoprotein levels in American Samoans

Distributions of alleles at three apolipoprotein loci (APO E, APO H, and APO A-IV) and an insertion/deletion (I/D) polymorphism at the angiotensin converting enzyme (ACE) locus among 274 American Samoans are described here. Genotypes at each locus are examined for associations with quantitative lipid (total cholesterol (total-c), LDL-cholesterol (LDL-c), HDL-cholesterol (HDL-c), and triglycerides) and apolipoprotein (APO AI, APO AII, APO E, and APO B) levels. Genotype frequencies at all four loci are in Hardy-Weinberg equilibrium. The most common APO A-IV genotype (1-1) was observed in 252 American Samoans (97%). The three most common APO E genotypes were 3-3 (47%), 3-4 (30%), and 2-3 (12%). The most frequent APO H genotype was 2-2 (86%). The most common ACE genotype (I/I) was observed in 75% of sampled individuals, and 23% were I/D heterozygotes. APO E genotypic variation was associated with total-c, HDL-c, LDL-c, and all four quantitative apolipoproteins (AI, AII, E, and B). APO A-IV genotypes were associated significantly with total cholesterol, LDL-c, and APO-B levels. APO H showed little association with any quantitative lipid or apolipoprotein. ACE D/D homozygotes had higher AII levels. ACE showed a consistent association with APO AII levels, with either APO A-IV or APO E as a covariate. The interaction term between ACE and APO E was also significantly associated with total-c and APO E levels, and the ACE genotype showed a significant main effect on APO AI levels in multivariate analyses.

Detection of apolipoprotein E phenotype in unconcentrated cerebrospinal fluid

We developed a simple method to detect apolipoprotein E (Apo E) polymorphism distribution in approximately 20 microL of unconcentrated cerebrospinal fluid (CSF). A combination of isoelectric focusing in 3 M urea gel and immunoblotting was employed. Apo E phenotypes were identified in CSF samples from 45 patients with probable Alzheimer disease (AD), 15 with multiple sclerosis (MS), and 25 with other neurological diseases (OND). When the data were compared with a set of matched plasma samples, the results were identical. The method is useful for Apo E phenotyping from fresh or frozen unconcentrated CSF, when blood or plasma is not available.

Bone loss predicts subsequent cognitive decline in older women: the study of osteoporotic fractures

OBJECTIVES

To determine whether the rate of bone loss predicts subsequent cognitive decline independently of baseline bone mass and whether apolipoprotein E (ApoE) genotype explains the association.

DESIGN

A prospective cohort study.

SETTING

Clinical centers in Baltimore, Maryland; Minneapolis, Minnesota; Pittsburgh, Pennsylvania; and Portland, Oregon.

PARTICIPANTS

Four thousand four hundred sixty-two women aged 70 and older (mean = 75.8) participating in the Study of Osteoporotic Fractures.

MEASUREMENTS

Total hipbone mineral density (BMD) was measured 2 and 6 years after enrollment (mean follow-up = 3.5 years), and expressed as annualized percentage rate of bone change. A modified Mini-Mental State Examination (mMMSE) was administered at 6 and 10 years (mean follow-up = 4.5 years) and defined cognitive decline as a decline of three or more points on repeat mMMSE score. ApoE genotype information was available on 883 women.

RESULTS

Cognitive decline occurred in 12% of the women with the least bone loss (by quartile), 14% in the second, 16% in the third, and 20% in those with the greatest bone loss. After adjustment for age, education, stroke, functional status, estrogen use, body mass index, and smoking, the results were similar. Those who lost the most BMD were almost 40% more likely than women in the lowest quartile to develop cognitive decline in the multivariate model (odds ratio (OR) = 1.4, 95% confidence interval (CI) = 1.1-1.8). A similar association between hipbone loss and cognitive decline was observed in the multivariate model further adjusting for ApoE e4 (OR = 1.5, 95% CI = 0.8-2.7).

CONCLUSIONS

Women with more rapid hipbone loss were more likely to develop cognitive decline than those who had lower rate of loss (or who gained bone mass). Differences in functional status, estrogen use, and ApoE did not explain this association. Further investigation is needed to determine the mechanisms that link osteoporosis and cognitive decline.

Risk factors for coronary heart disease in type 1 diabetic children: the influence of apoE phenotype and glycemic regulation

The effects of apolipoprotein E (apoE) phenotype and glycemic regulation on plasma levels of lipids and lipoproteins, low density lipoprotein (LDL) composition, LDL particle size, and LDL oxidation were examined in 35 type 1 diabetic children aged 5-12 years. All subjects were classified according to glycemic regulation (HbA(1c)<8% vs. HbA(1c)>8%). ApoE phenotypes were identified by isoelectric focusing (IEF) followed by immunoblotting. Results from two-way analysis of variance (ANOVA) showed that subjects with apoE 4/3 and HbA(1c)>8% had higher concentrations of total cholesterol (TC), LDL-cholesterol (LDL-C), and LDL-cholesterol ester (LDL-CE) than subjects with the same apoE phenotype and HbA(1c)<8%. LDL particles in all subjects were classified as the subclass pattern A. Both LDL particle size and susceptibility of LDL to oxidation were not different among subjects stratified by apoE phenotype. In conclusion, children with type 1 diabetes mellitus included in this study did not have high-risk lipoprotein profiles at this early stage of life. However, there was some indication that those with the apoE 4/3 phenotype were more likely to have more favorable lipid profiles when HbA(1c) levels were <8%.

Phenotype of apolipoprotein E influences the lipid metabolic response of postmenopausal women to hormone replacement therapy

OBJECTIVES

We investigated whether the phenotype of apolipoprotein E (apo E) would influence the response of postmenopausal Japanese women to hormone replacement therapy (HRT).

METHODS

We measured the plasma levels of lipoprotein and apolipoprotein in 242 postmenopausal women at baseline and again after 12 months of HRT. Patients were divided into three groups according to apo E phenotype: E2+ (E2/2 and E2/3, n=21), E3/3 (n=176), E4+ (E3/4 and E4/4, n=45).

RESULTS

We found that the E4+ group had the highest levels of total and low density lipoprotein (LDL) cholesterol and apolipoprotein B, being significantly higher than in the E2+ group at baseline. The plasma levels of total and LDL cholesterol showed a significant decrease only in the E2+ and E3/3 groups after 12 months of HRT (E2+ group, total cholesterol -8.9% and LDL cholesterol -21.5%; E3/3 group, total cholesterol -2.9% and LDL cholesterol -9.5%). No significant difference in the reduction of total and LDL cholesterol was found in the E4+ group. Other lipid parameters did not differ in the three groups.

CONCLUSIONS

These data show that the apo E phenotype influenced the response of lipid metabolism in postmenopausal women to HRT, especially in the reduction of LDL cholesterol. Therefore, apo E phenotyping may be important in predicting the cholesterol-lowering effect of HRT.

Discrepancies between apolipoprotein E phenotyping and genotyping in the elderly

We estimated the frequencies of phenotype (isoelectric focusing; IEF) vs. genotype (PCR/Hhal) discordance in a sample of an aged population (> 65 years). Both phenotype and genotype techniques have been used in the study of apolipoprotein E (apoE) polymorphism in 125 elderly subjects. The discordance between phenotype and genotype was unresolved in 11 (8.8%) of the 125 unrelated subjects studied. We observed a significant association between the presence of the E4 allele and both Alzheimer's disease (chi2 = 13, p < 0.001) and increased cholesterol concentration (Mann Whitney, p < 0.03). These relationships were not affected by the techniques used. Our results indicate that transcriptional modulation and post-transductional modifications in normal ageing and in aged-related diseases may explain in part discrepancies between gene analysis and protein characterisation.

Apolipoprotein E epsilon4 and tardive dyskinesia in a Japanese population

The findings that free radicals play a causative role in the occurrence of tardive dyskinesia (TD) and that apolipoprotein E (ApoE) 4 has decreased anti-oxidant activity suggest a potential link between TD and ApoE alleles. We, therefore, examined ApoE allelic frequencies in schizophrenic subjects with TD and non-TD. Serum samples were obtained from 333 DSM IV-diagnosed schizophrenic patients and 191 controls in Japan. The presence of TD was evaluated by research diagnostic criteria for TD. ApoE phenotypes of the serum samples were determined by polyacrylamide gel isoelectricfocusing. A total of 62 TD subjects (31 males, 31 females) were identified among all patients examined. No significant differences in ApoE allelic frequency were found between TD and non-TD groups. ApoE epsilon4 allele frequency, however, was significantly lower in the female TD group than in the male TD group. These findings do not clearly demonstrate a certain association between TD and the epsilon4 allele, but may preliminarily reveal a difference in influence of this allele on the development of TD between males and females.

Apolipoprotein E phenotype, arterial disease, and mortality among older women: the study of osteoporotic fractures

This study is an investigation of the relationship between apolipoprotein E (apoE) phenotype, arterial disease, and mortality in a group of women (n = 1,751) aged 65 years and older enrolled in the Study of Osteoporotic Fractures. Crude mortality rates were highest among women with the 4-3 and 4-4 phenotypes but age-adjusted mortality showed no statistically significant variations across the phenotype groups. Using multivariate analysis, the mortality experience of women with 4-3 or 4-4 apoE phenotypes was compared to that of women with the 3-3 phenotype: no significant excess total mortality was found [relative risk (RR) = 1.2, 95% confidence interval (CI) 0.8, 1.8] among women with the epsilon 4 allele. Similarly, neither cardiovascular (RR = 0.9. 95% CI 0.5, 1.8) nor cancer (RR = 1.5, 95% CI 0.8, 2.8) mortality rates were significantly different in this group of women. Inclusion of cholesterol levels in the regression models did not change the relative mortality risks. Among women 65-69 year of age epsilon 4 was associated with an approximate doubling of RR for death due to both cardiovascular disease and cancer. No association was found between apoE phenotype and the presence of lower extremity arterial disease (defined as an ankle/arm index of 0.9 or less). These results suggest that women with the epsilon 4 who survive to age 70 years or beyond have a life expectancy that is similar to that for women homozygous for the 3 allele who comprise the majority of the population.

Mechanisms mediating lipoprotein responses to diets with medium-chain triglyceride and lauric acid

Medium-chain triglycerides (MCT) are often used in specialized formula diets or designer fats because of their special properties. Yet their influence on lipid metabolism is not completely understood. In this two-period cross-over study, the effects of MCT (8:0 + 10:0) in contrast to a similar saturated fatty acid (12:0) were compared. Eighteen healthy women ate a baseline diet [polyunsaturated (PUFA)/saturated fat = 0.9] for 1 wk. Then, they consumed test diets (PUFA/saturated fat = 0.2) for 4 wk. Monounsaturated fat and cholesterol were constant in baseline and treatment diets. MCT and 12:0, substituted for part of the PUFA, provided 14 energy (en)% of the test diets. In comparison to the PUFA baseline diet, a 16% increase in mean serum low density lipoprotein (LDL)-cholesterol (C) on the 12:0 diet was accompanied by a 21% decrease in mean receptor-mediated degradation of LDL by freshly isolated mononuclear cells (MNC) in vitro. The MNC assay theoretically gives an indication of receptor-mediated degradation of LDL. In contrast, the MCT diet raised mean receptor-mediated degradation of LDL by 42%, a finding out of line with the mean 11% increase in serum LDL-C. Perhaps MCT, by increasing the rate of LDL-C production, overcame the rate of LDL-C clearance. The 12:0 diet enhanced some factors involved in reverse cholesterol transport (e.g., high density lipoprotein fractions) while MCT had a different or less pronounced effect. The overall effects of MCT on cholesterol metabolism may or may not be desirable, whereas those of 12:0 appear largely undesirable as previously reported.

Apolipoprotein E polymorphism: A new genetic marker of hip fracture risk--The Study of Osteoporotic Fractures

Hip fractures are common and devastating events. The apolipoprotein E*4 (APOE) allele, associated with Alzheimer's disease, has also been associated with osteoporosis in hemodialysis patients. We prospectively studied 1750 women, age >/=65 years, who underwent measurements of hip and calcaneal bone mineral density (BMD), were typed for APOE and followed for approximately 7.0 years for the occurrence of fractures and falls. Women with at least one APOE*4 allele had an increased risk of hip fracture, relative hazard (RH) (95% confidence interval) = 1.90 (1.05-3.41) and wrist fracture, RH = 1.67 (1.01-2.77) compared with women without APOE*4, even after adjusting for age, cognitive function, falling, and BMD. The effect of APOE*4 on hip fracture was greatest among women with additional (>/=3) other risk factors. Women with an APOE*4 allele were also likely to report a maternal history of fracture. The average number of falls per year did not differ by APOE*4: 0.46 for APOE*4 women and 0.41 for women without an APOE*4 allele. Women with an APOE*4 allele experienced greater weight loss which contributed to faster rates of bone loss. We conclude that women with the APOE*4 polymorphism are at substantially increased risk of hip and wrist fracture that is not explained by bone density, impaired cognitive function, or falling. Possible alternate explanations include an effect of APOE on vitamin K, bone turnover, or weight loss. The APOE polymorphism may be a candidate gene for hip fractures among community dwelling nondemented women.

Apolipoprotein E phenotype associations with plasma lipoproteins and bone mass in postmenopausal women

OBJECTIVE

The aim of the study was to investigate the effects of apolipoprotein E (apo E) phenotype on plasma lipids and bone mass in postmenopausal Japanese women.

METHODS

In 320 subjects aged 40-65 years (mean +/- SE, 54.0 +/- 0.6), apo E phenotype was determined by isometric electrophoresis. Phenotypic frequencies were 0.3% for E2/2 (n = 1), 8.1% for E3/2 (n = 26), 70.3% for E3/3 (n = 225), 0.6% for E4/2 (n = 2), 19.4% for E4/3 (n = 62) and 1.3% for E4/4 (n = 4). Apo E2/2 and apo E3/2 were classified as E2+ (n = 27); apo E3 homozygotes were placed in another group (E3/3; n = 225), as were apo E4/3 together with apo E4/4 subjects (group E4+; n = 66). Bone density and bone quality were assessed with a newly developed ultrasonic bone densitometer, and plasma lipids were also measured.

RESULTS

Age, body mass index and years since menopause did not differ significantly between the three groups. The E4+ group had the highest levels of total cholesterol, low-density lipoprotein cholesterol and apolipoprotein B, significantly higher than in the E2+ group. Plasma lipoprotein(a) concentrations were significantly higher in the E4+ group than in the other two groups. Ultrasonic parameters of bone density and quality tended to be lower in the E4+ group than in the E2+ group.

CONCLUSIONS

The apo E4 allele was associated with high plasma cholesterol levels and an unfavorable change of bone structure in postmenopausal women.

The relationship between apolipoprotein E and serum oxidation-related variables is apolipoprotein E phenotype dependent

To examine the relationship between apolipoprotein E and serum oxidation status, we assayed apolipoprotein E level, apolipoprotein E phenotype, and levels of lipid peroxides and transition metal ions and their binding proteins in sera from apparently healthy individuals. The study group included 129 women aged 22-63 years and 53 men aged 22-56 years. Among subjects with apolipoprotein E 4/3 phenotype, lipid peroxide levels were higher compared with E 3/2 phenotype (786 +/- 182 nmol/l vs. 659 +/- 174 nmol/l, P = 0.015), and ceruloplasmin levels were slightly higher compared with apolipoprotein E 3/3 phenotype (0.28 +/- 0.08 mg/l vs. 0.26 +/- 0.06 mg/l, P = 0.035). In the study group as a whole, there were significant associations between serum apolipoprotein E level, and serum levels of ceruloplasmin (r = 0.266, P < 0.001) and ferritin (r = 0.2, P < 0.007). Among subjects with apolipoprotein E 4/3 phenotype, there was a significant association between serum apolipoprotein E and lipid peroxide levels (r = 0.470, P < 0.01), which was not apparent among subjects with E 3/3 or E 3/2 phenotypes. In multivariate analysis, apolipoprotein E phenotype was a small but significant independent contributor to variation in serum lipid peroxide levels. These data suggest that there may be heterogeneity among apolipoprotein E phenotypes in their relationships with serum lipid oxidation status.

Influence of apoE content on receptor binding of large, bouyant LDL in subjects with different LDL subclass phenotypes

We investigated the influence of apolipoprotein (apo) E-containing particles on LDL receptor binding of large, buoyant LDL subfractions (LDL I) from subjects with predominantly large (phenotype A) and small (phenotype B) LDL particles. Direct binding by human fibroblast LDL receptors was tested at 4 degrees C before and after removal of apoE-containing particles by immunoaffinity chromatography. The binding affinity of total LDL I in phenotype B was greater than that in phenotype A (Kd of 1.83+/-0.3 and 3.43+/-0.9 nmol/L, respectively, P<.05). LDL I from phenotype B subjects had a higher apoE to apoB molar ratio than did that from phenotype A (0.16+/-0.04 versus 0.06+/-0.02, P<.05). Nondenaturing gradient gel electrophoresis of apoE-containing LDL I isolated by immunoaffinity chromatography revealed a substantially larger peak particle diameter than in apoE-free LDL I, and comparison of LDL I composition before and after immunoaffinity chromatography suggested an increase in triglyceride content of apoE-containing particles. After removal of these particles, there was a greater than twofold reduction in LDL receptor affinity of phenotype B LDL (Kd of 1.83+/-0.3 to 3.76+/-0.6, P<.01), whereas in phenotype A no change was observed (Kd of 3.43+/-0.9 to 3.57+/-0.4, respectively). The receptor affinity of apoE-free LDL I from phenotype A and B subjects did not differ. These findings confirm that large, buoyant LDL particles from phenotype B subjects have a higher LDL receptor affinity than does LDL I from phenotype A subjects and suggest that this difference is due to an increased content of large, triglyceride-enriched, apoE-containing lipoproteins. It is possible that the accumulation of these particles reflects abnormalities in the metabolism of remnant lipoproteins that contribute to atherosclerosis risk in phenotype B subjects.

Effect of apolipoprotein E polymorphism on serum lipoprotein response to saturated fatty acids

This report summarizes two studies which investigated the effects of apolipoprotein E (apoE) polymorphism on the serum total cholesterol (TC) and lipoprotein cholesterol responses to 8:0 + 10:0 and 12:0 diets (Study I) and 14:0, 16:0 and 18:0 diets (Study II). Eighteen healthy premenopausal women (3 apoE 3/2, 12 apoE 3/3, 3 apoE 4/3) in study I and another 18 healthy premenopausal women (4 apoE 3/2, 10 apoE 3/3, 3 apoE 4/3, 1 apoE 4/2) in study II consumed a baseline diet providing 40 en% total fat, 11 en% 18:2, 15 en% 18:1, 11.5 en% saturated fat for the first week of each 5-wk period. The experimental diets for both studies provided 40 en% total fat, 13-14 en% as one of five test saturated fatty acids (SFA), 14-16 en% 18:1, and 3-4 en% 18:2. Analysis by apoE phenotypes showed that both the 8:0 + 10:0 diet and the 12:0 diet in Study I induced significant increases in serum TC in subjects with different apoE phenotypes with the exception of apoE 3/2 in the medium-chain triglyceride group. In contrast, in Study II, individuals with apoE 4/3 consuming the 14:0 diet showed significant increases in serum TC, high density lipoprotein-cholesterol (HDL-C), and HDL2-C, but the same subjects consuming the 16:0 diet showed significant increases in serum TC and low density lipoprotein-cholesterol. The findings from both studies indicated serum lipoprotein responses to SFA were different and the variation of responsiveness may be regulated, at least in part, by apoE polymorphism, especially when 14:0, 16:0, or 18:0 was consumed.

Relation of LDL size to the insulin resistance syndrome and coronary heart disease in American Indians. The Strong Heart Study

Small, dense LDL has been shown to be associated with the insulin resistance syndrome and coronary heart disease (CHD). We examined the distribution of LDL size and phenotype within a population-based sample of American Indians to determine the relationships with prevalent CHD and to examine associations with hyperinsulinemia and other components of the insulin resistance syndrome. Data were available for 4505 men and women between 45 and 74 years of age who are members of 13 American Indian communities in three geographic areas. Diabetes, CHD, and CHD risk factors were assessed by standardized techniques, and LDL size was measured by gradient gel electrophoresis. LDL size was smaller in men than in women and in individuals with diabetes than in those without diabetes. In multivariate analysis, LDL size was significantly related to several components of the insulin resistance syndrome, including triglycerides (inversely) and HDL cholesterol (positively). Although univariate relations were positive, LDL size was not significantly related to fasting insulin concentrations or body mass index in the multivariate model. LDL size also showed no relationship to apolipoprotein E phenotype. When LDL size was compared in individuals with and without CHD, no significant differences were observed, either in nondiabetic or diabetic individuals. We conclude that LDL size is most strongly related to lipoprotein components of the insulin resistance syndrome, especially plasma triglycerides. However, in this population with low LDL, it is not related to cardiovascular disease.

Association of bone mineral density with apolipoprotein E phenotype

The phenotypes of apolipoprotein E (Apo E) and their relationship with the bone mineral density (BMD) were examined in 284 unrelated postmenopausal Japanese women aged 47-82 years (64.0 +/- 1.0 years, mean +/- SE). The Apo E phenotype was analyzed by the isoelectric focusing method, followed by immunoblotting. The relationship between the Apo E phenotype and the vitamin D receptor (VDR) gene or estrogen receptor (ER) gene genotypes was also studied in the same population. The Apo E phenotypic frequencies in our population were 9.9% for E3/2, 66.5% for E3/3, 1.8% for E4/2, 19.7% for E4/3, and 2.1% for E4/4. We classified these phenotypes into three categories: Apo E4-/- (E3/2 and E3/3, n = 217, Apo E4 +/- (E4/3 and E4/2, n = 61), and Apo E4+/+ (E4/4, n = 6). The age, body weight, body height, and years since menopause were not significantly different among these three categories. The lumbar BMD values in these three groups were significantly different in the order of E4-/- (0.91 +/- 0.01 g/cm2), E4 +/- (0.85 +/- 0.02 g/cm2), and E4+/+ (0.83 +/- 0.06 g/cm2) (p = 0.031). The same trend was also observed for the Z score of the total BMD (p = 0.022). The serum level of intact osteocalcin in E4+/+ (15.2 +/- 5.7 ng/ml) was higher than in E4-/- (7.7 +/- 0.3 ng/ml) or E4 +/- (7.7 +/- 0.7 ng/ml) (p = 0.004 by analysis of variance). However, there were no other significant differences in the serum or urinary levels of bone turnover markers. Serum cholesterol in the E4+/+ group tended to be higher than in the other two groups (p = 0.05). There were no significant associations of the VDR and ER genotypes with the Apo E4 phenotype. A multivariate linear regression analysis revealed Apo E4 to be a significant, independent predictor of the Z score of the lumbar BMD. The effect of the Apo E4 allele on the Z score of the lumbar BMD (-0.493 +/- 0.152) was not significantly different from that in the AAB of VDR (-0.616 +/- 0.225) or PPxx of ER (-0.785 +/- 0.314). In conclusion, the Apo E4 allele is associated with a low bone mass in postmenopausal Japanese.

Apolipoprotein E epsilon2 allele and early onset schizophrenia

To explore the role of apolipoprotein E (ApoE) in schizophrenia, we investigated ApoE phenotypes in a group of patients with schizophrenia. Serum samples were obtained from 122 schizophrenic patients and 126 controls in Japan and were examined using isoelectric focusing/immunoblotting. This experiment showed a trend toward a decreased frequency of ApoE epsilon4 in schizophrenia and no link between ApoE epsilon4 and familial schizophrenia or early onset schizophrenia. On the other hand, a decreased frequency of ApoE epsilon2 in early onset schizophrenia was detected. These results suggest that ApoE epsilon2 protects against early onset schizophrenia, and that ApoE epsilon4 is not involved in the development of schizophrenia in Japanese.