Total Cholesterol and APOE-Related Risk for Alzheimer’s Disease in the Alzheimer’s Disease Neuroimaging Initiative

2021 ◽  
pp. 1-10
Author(s):  
Michelle M. Dunk ◽  
Ira Driscoll ◽  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Total Cholesterol ◽  
Cholesterol Metabolism ◽  
Apoe Genotype ◽  
Control Group ◽  
Cholesterol Levels ◽  
Related Risk ◽  
E4 Allele

Background: APOE ɛ4 allele confers greatest genetic risk for Alzheimer’s disease (AD), yet mechanisms underlying this risk remain elusive. APOE is involved in lipid metabolism, and literature suggest relationships between high total cholesterol, APOE, and AD. Further investigation is needed to elucidate the potential role of total cholesterol in AD risk. Objective: To investigate the relationship between total cholesterol and APOE-related AD risk in the Alzheimer’s Disease Neuroimaging Initiative. Methods: Participants (N = 1,534) were classified as controls (cognitively normal; N = 404), early mild cognitive impairment (MCI; N = 294), late MCI (N = 539), or AD (N = 297). Total cholesterol levels were compared across APOE genotype and diagnosis. Mendelian randomization was performed to examine causality between total cholesterol and AD risk using APOE as a genetic instrument. Results: Total cholesterol was higher in APOE4+ compared to APOE3 and APOE2+ (ps < 0.04) carriers. Those with AD and late MCI (ps < 0.001) had higher total cholesterol than the control group. Comparing APOE4+ to APOE3 carriers, the predicted odds ratios per mg/dL greater total cholesterol were 1.11 for MCI (95% confidence interval, 1.04–7.32), 1.05 for early MCI (1.01–3.22), 1.13 for late MCI (1.05–11.70), 1.21 for AD (1.09–54.05), and 1.13 for composite dementia (MCI or AD; 1.06–11.59) (ps < 0.05, F-statistics>10). Conclusion: Higher total cholesterol may be a significant contributor to AD risk, particularly in APOE4 carriers who, based on existing literature, tend to have impaired cholesterol metabolism. Our findings highlight a possible mechanism by which APOE confers AD risk and indicate potential for AD risk modification through maintenance of healthy total cholesterol levels.

scholarly journals Abnormal brain cholesterol homeostasis in Alzheimer’s disease—a targeted metabolomic and transcriptomic study

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Vijay R. Varma ◽  
H. Büşra Lüleci ◽  
Anup M. Oommen ◽  
Sudhir Varma ◽  
Chad T. Blackshear ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Brain Tissue ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Cholesterol Homeostasis ◽  
Transcriptomic Data ◽  
Brain Cholesterol ◽  
Cholesterol Levels

AbstractThe role of brain cholesterol metabolism in Alzheimer’s disease (AD) remains unclear. Peripheral and brain cholesterol levels are largely independent due to the impermeability of the blood brain barrier (BBB), highlighting the importance of studying the role of brain cholesterol homeostasis in AD. We first tested whether metabolite markers of brain cholesterol biosynthesis and catabolism were altered in AD and associated with AD pathology using linear mixed-effects models in two brain autopsy samples from the Baltimore Longitudinal Study of Aging (BLSA) and the Religious Orders Study (ROS). We next tested whether genetic regulators of brain cholesterol biosynthesis and catabolism were altered in AD using the ANOVA test in publicly available brain tissue transcriptomic datasets. Finally, using regional brain transcriptomic data, we performed genome-scale metabolic network modeling to assess alterations in cholesterol biosynthesis and catabolism reactions in AD. We show that AD is associated with pervasive abnormalities in cholesterol biosynthesis and catabolism. Using transcriptomic data from Parkinson’s disease (PD) brain tissue samples, we found that gene expression alterations identified in AD were not observed in PD, suggesting that these changes may be specific to AD. Our results suggest that reduced de novo cholesterol biosynthesis may occur in response to impaired enzymatic cholesterol catabolism and efflux to maintain brain cholesterol levels in AD. This is accompanied by the accumulation of nonenzymatically generated cytotoxic oxysterols. Our results set the stage for experimental studies to address whether abnormalities in cholesterol metabolism are plausible therapeutic targets in AD.

scholarly journals Increasing Membrane Cholesterol Level Increases the Amyloidogenic Peptide by Enhancing the Expression of Phospholipase C

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Yoon Sun Chun ◽  
Hyun Geun Oh ◽  
Myoung Kyu Park ◽  
Tae-Wan Kim ◽  
Sungkwon Chung
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Phospholipase C ◽  
Cholesterol Level ◽  
Cholesterol Metabolism ◽  
Membrane Cholesterol ◽  
Neuronal Dysfunction ◽  
Carrier System ◽  
Cholesterol Levels

Cerebral elevation of 42-residue amyloid β-peptide (Aβ42) triggers neuronal dysfunction in Alzheimer's disease (AD). Even though a number of cholesterol modulating agents have been shown to affect Aβ generation, the role of cholesterol in the pathogenesis of AD is not clear yet. Recently, we have shown that increased membrane cholesterol levels downregulates phosphatidylinositol 4,5-bisphosphate (PIP2) via activation of phospholipase C (PLC). In this study, we tested whether membrane cholesterol levels may affect the Aβ42 production via changing PIP2 levels. Increasing membrane cholesterol levels decreased PIP2 and increased secreted Aβ42. Supplying PIP2, by using a PIP2-carrier system, blocked the effect of cholesterol on Aβ42. We also found that cholesterol increased the expressions of β1 and β3 PLC isoforms (PLCβ1, PLCβ3). Silencing the expression of PLCβ1 prevented the effects of cholesterol on PIP2 levels as well as on Aβ42 production, suggesting that increased membrane cholesterol levels increased secreted Aβ42 by downregulating PIP2 via enhancing the expression of PLCβ1. Thus, cholesterol metabolism may be linked to Aβ42 levels via PLCβ1 expression and subsequent changes in PIP2 metabolism.

Novel Therapeutic Mechanism of Action of Metformin and Its Nanoformulation in Alzheimer's Disease and Role of AKT/ERK/GSK Pathway.

2021 ◽  
Author(s):  
Harish Kumar ◽  
Amitava Chakrabarti ◽  
Phulen Sarma ◽  
Manish Modi ◽  
Dibyajyoti Banerjee ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Disease Control ◽  
Rat Model ◽  
Memory Impairment ◽  
Protective Efficacy ◽  
Control Group ◽  
Hyperphosphorylated Tau ◽  
Days Of Therapy

Abstract Background: Insulin resistance in brain plays a critical role in the pathogenesis of Alzheimer's disease (AD). Metformin is a blood brain barrier crossing anti-diabetic insulin-sensitizer drug. Current study has evaluated the therapeutic and mechanistic role of conventional as well as solid lipid nanoformulation (SLN) of metformin in intracerebro ventricular (ICV) Aβ (1-42) rat-model of AD. Methods: SLN-metformin was prepared by the micro-emulsification method and further evaluated by zetasizer and scanning electron-microscopy. In the animal experimental phase, AD was induced by bilateral ICV injection of Aβ using stereotaxic technique, whereas control group (sham) received ICV-NS. 14 days post-model induction, ICV- Aβ treated rats were further divided into 5 groups: disease control (no treatment), Metformin dose of (50mg/kg, 100mg/kg and 150 mg/kg), SLN of metformin 50mg/kg and memantine 1.8mg/kg (positive-control). Animals were tested for cognitive performance (in EPM, MWM) after 21 days of therapy, and then sacrificed. Brain homogenate was evaluated using ELISA for (Aβ (1-42), hyperphosphorylated tau, pAKTser473, GSK-3β, p-ERK,) and HPLC (metformin level). Brain histopathology was used to evaluate neuronal injury score (H&E) and Bcl2 and BAX (IHC). Results: The average size of SLN-metformin was <200 nm and was of spherical in shape with 94.08% entrapment efficiency. Compared to sham, the disease-control group showed significantly higher (p≤0.05) memory impairment (in MWM and EPM), higher hyperphosphorylated tau, Aβ (1-42), and Bax and lower Bcl-2 expression. Metformin was detectable in brain. Treatment with metformin and its SLN form significantly decreased the memory impairment as well as decreased the expression of hyperphosphorylated tau, Aβ(1-42), Bax expression and increased expression of Bcl-2 in brain. AKT-ERK-GSK3β-Hyperphosphorylated tau pathway can be implicated in the protective efficacy of metformin. Conclusion: Both metformin and SLN metformin is found to be effective as therapeutic agent in ICV-AB rat model of AD. AKT-ERK-GSK3β-Hyperphosphorylated tau pathway is found to be involved in the protective efficacy of metformin.

The Role of Cholesterol Metabolism in Alzheimer’s Disease

2014 ◽  
Vol 51 (3) ◽  
pp. 947-965 ◽  
Author(s):  
Jia-Hao Sun ◽  
Jin-Tai Yu ◽  
Lan Tan
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cholesterol Metabolism

The Application Value of ApoE Gene Polymorphism in Alzheimer's Disease

2019 ◽  
Vol 9 (10) ◽  
pp. 1403-1407
Author(s):  
Cong Chen ◽  
Yuhui Zhang ◽  
Bin Chen ◽  
Chaosheng Zeng ◽  
Min Chen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gene Polymorphism ◽  
Apoe Genotype ◽  
Apoe Gene ◽  
Control Group ◽  
Apolipoprotein E Polymorphism ◽  
Abnormal Lipid Metabolism ◽  
And Control ◽  
Apoe Gene Polymorphism

To explore the association of apolipoprotein E polymorphism with Alzheimer's disease (AD), so as to provide possible research value for potential targeted therapy. 120 AD patients and 50 healthy volunteers were enrolled to extract fasting blood samples. ApoE gene polymorphism and blood lipids were tested in blood. ApoE gene and genotype frequency between AD group and control group were compared by PCR and sequencing methods. MMSE, CDR, and BPSD were used to determine the intelligence. ApoE genotype was detected by DNA microarray. ɛ4 carrier accounted for 45% in AD group, which was significantly elevated compared with control group (12%) (P < 0.05). TG, TC, and LDL-C levels were increased, while HDL-C was reduced in ɛ4 allele carriers (allP < 0.05). The MMSE scores of ApoEɛ4 genotype carriers in AD group were markedly lower than those of nonApoEɛ4 genotype carriers (P < 0.05) and control (P < 0.01). The proportion of dementia in ApoEɛ4 genotype carriers from AD group was apparently higher than the ɛ4 gene non-carriers (P < 0.05). The ApoEɛ4 gene is an AD risk factor. The changes of genotype and frequency of ApoEɛ4 gene are the main factors leading to abnormal lipid metabolism in AD patients, suggesting that ApoEɛ4 gene detection might be helpful for the early diagnosis and treatment of AD.

Pattern and Progression of Cognitive Decline in Alzheimer’s Disease: Role of Premorbid Intelligence and ApoE Genotype

2007 ◽  
Vol 24 (6) ◽  
pp. 483-491 ◽  
Author(s):  
Laura Bracco ◽  
Carolina Piccini ◽  
Michela Baccini ◽  
Valentina Bessi ◽  
Federica Biancucci ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Decline ◽  
Apoe Genotype ◽  
Premorbid Intelligence

scholarly journals Resting state brain signal complexity of young healthy adults reflects genetic risk for developing Alzheimer’s Disease

2020 ◽  
Author(s):  
Xiaojing Li ◽  
Yadwinder Kaur ◽  
Oliver Wilhelm ◽  
Martin Reuter ◽  
Christian Montag ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Performance ◽  
Time Scales ◽  
Fluid Intelligence ◽  
Brain Activity ◽  
Apoe Genotype ◽  
Healthy Adults ◽  
Signal Complexity ◽  
E4 Allele

AbstractThe e4 allele of the APOE gene is strongly associated with impaired brain functionality and cognitive decline in humans at older age. It is controversial whether and how the APOE e4 allele is affecting brain activity among young healthy individuals and how such effects may contribute to individual differences in cognitive performance. Signal complexity is a critical aspect of brain activity that has been shown to be associated with brain function. In this study, we analyzed multiscale entropy (MSE) of EEG signals among young healthy adults as an indicator of brain signal complexity and investigated how MSE is predicted by APOE genotype groups. Furthermore, by means of structural equation modeling, we investigated whether MSE predicts fluid intelligence. Results indicate larger MSE in young healthy e4 carriers across all time scales. Moreover, better fluid intelligence (gf) is associated with smaller MSE at low time scales and larger MSE at higher scales. However, MSE does not account for better cognitive performance among APOE e4 carriers by mediating the APOE genotype effect on fluid intelligence. The present results shed further light on the neural mechanisms underlying gene-behavior association relevant for Alzheimer’s Disease risk.

scholarly journals The role of impairment of higher mental functions in suicidogenesis in the dementia caused by Alzheimer's disease

2018 ◽  
Vol 3 (3) ◽  
pp. e0303104
Author(s):  
Iryna Mudrenko
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
High Risk ◽  
Suicidal Behavior ◽  
Control Group ◽  
Elderly Age ◽  
Mental Functions ◽  
Age Related ◽  
Higher Mental Functions

Background Dementia is the age-related disease. At the same time, the elderly age has one of the peaks in the number of suicides. Psychology of patients with demetia is characterized by the feeling of hopelessness, pessimism, awareness of own insolvency, dependence on others, that affects the risk of suicide. It is established that the highest risk of suicide in the early stages of dementia with the progression of cognitive deficit, the risk of suicide decreases. Aim To study the role of impairment of higher mental functions (perception, reasoning, attention, memory, emotions, will, speech) in the formation of suicidal behaviour in patients with dementia in Alzheimer's disease. Materials and methods There were examined 75 patients with dementia in Alzheimer's disease, 36 patients with a history of suicidal behavior composed the main group, and 39 patients without the signs of suicidal behavior composed control group. The study was carried out using clinical-anamnestic, psychopathological methods and mathematical statistical methods. Results The high risk of suicide in dementia caused by Alzheimer's disease is combined with the inhibition of thinking, the delusional ideas of self-blame and self-effacement (p ≤ 0.05); depressed mood, inner agitation, anxiety, feeling of despair, hopelessness, guilt, melancholia, apathy (p ≤ 0.05); effector-volitional disorders in the form of hypobulia, hypokinesia, hypomimia, decreased libido (p ≤ 0.05); speech disturbance in the form of bradylalia p ≤ 0.05; greater exhaustion and decreased attention (p ≤ 0.05). On the contrary, the following peculiarities of higher mental functions, namely thought disorder are referred to the anti-risk factors of suicide in dementia caused by Alzheimer's disease: the delusional ideas of relation and damage (p ≤ 0.05); emotions: the feeling of fear (p ≤ 0.05); effector-volitional sphere: parabulia and hyperkinesia (p ≤ 0.05). Conclusion On the basis of clinical and psychopathological study of patients with dementia in Alzheimer's disease, the specific impairment of higher mental functions and emotional-volitional spheres reasoning, memory, attention, perception, speech, emotions) are identified associated with high risk of suicide.

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