Apolipoprotein E genotype, cardiovascular biomarkers and risk of stroke: systematic review and meta-analysis of 14,015 stroke cases and pooled analysis of primary biomarker data from up to 60,883 individuals

Genetic polymorphisms and their correlation with dyslipidemia in Chinese patients diagnosed with diabetes mellitus

BACKGROUND

Dyslipidemia is a common complication in patients with diabetes mellitus (DM) that increases the risk of cardiovascular disease. Genetic polymorphisms have been implicated in the development of dyslipidemia.

AIM

To investigate the association between polymorphisms of candidate genes involved in lipid metabolism and dyslipidemia in Chinese patients with DM.

METHODS

A cross-sectional study was conducted on 1098 Chinese patients with DM recruited from multiple healthcare centers. Demographic and clinical data were collected, and dyslipidemia was defined according to the National Cholesterol Education Program Adult Treatment Panel III guidelines. Genomic DNA was extracted from blood samples and genotyping for selected polymorphisms of candidate genes (APOE, LPL, CETP, and others) was performed using PCR and DNA sequencing techniques. Statistical analyses were performed using logistic regression models adjusted for potential confounding factors.

RESULTS

The study population consisted of 578 males (52.6%) and 520 females (47.4%), with a mean age of 58.4 ± 12.2 years. The prevalence of dyslipidemia was 64.8%. Significant associations were found between dyslipidemia and the APOE rs7412 T/T, APOE rs429358 C/C, LPL rs328 G/G, and CETP rs708272 G/G genotypes after adjusting for covariates. Subgroup analyses showed generally consistent associations across subgroups, although some variations in effect sizes were observed.

CONCLUSION

This study identified significant associations between genetic polymorphisms of APOE, LPL, and CETP genes and dyslipidemia in Chinese patients with DM.

Cognitive deficits in human ApoE4 knock-in mice: A systematic review and meta-analysis

Apolipoprotein-E4 (ApoE4) is an important genetic risk factor for Alzheimer's disease. The development of targeted-replacement human ApoE knock-in mice facilitates research into mechanisms by which ApoE4 affects the brain. We performed meta-analyses and meta-regression analyses to examine differences in cognitive performance between ApoE4 and ApoE3 mice. We included 61 studies in which at least one of the following tests was assessed: Morris Water Maze (MWM), novel object location (NL), novel object recognition (NO) and Fear Conditioning (FC) test. ApoE4 vs. ApoE3 mice performed significantly worse on the MWM (several outcomes, 0.17 ≤ g ≤ 0.60), NO (exploration, g=0.33; index, g=0.44) and FC (contextual, g=0.49). ApoE4 vs. ApoE3 differences were not systematically related to sex or age. We conclude that ApoE4 knock-in mice in a non-AD condition show some, but limited cognitive deficits, regardless of sex and age. These effects suggest an intrinsic vulnerability in ApoE4 mice that may become more pronounced under additional brain load, as seen in neurodegenerative diseases.

Genetics of ischemic stroke functional outcome

Ischemic stroke, which accounts for 87% of cerebrovascular accidents, is responsible for massive global burden both in terms of economic cost and personal hardship. Many stroke survivors face long-term disability-a phenotype associated with an increasing number of genetic variants. While clinical variables such as stroke severity greatly impact recovery, genetic polymorphisms linked to functional outcome may offer physicians a unique opportunity to deliver personalized care based on their patient's genetic makeup, leading to improved outcomes. A comprehensive catalogue of the variants at play is required for such an approach. In this review, we compile and describe the polymorphisms associated with outcome scores such as modified Rankin Scale and Barthel Index. Our search identified 74 known genetic polymorphisms spread across 48 features associated with various poststroke disability metrics. The known variants span diverse biological systems and are related to inflammation, vascular homeostasis, growth factors, metabolism, the p53 regulatory pathway, and mitochondrial variation. Understanding how these variants influence functional outcome may be helpful in maximizing poststroke recovery.

APOE ε4 carriage associates with improved myocardial performance from adolescence to older age

BACKGROUND

Although APOE ε4 allele carriage confers a risk for coronary artery disease, its persistence in humans might be explained by certain survival advantages (antagonistic pleiotropy).

METHODS

Combining data from ~ 37,000 persons from three older age British cohorts (1946 National Survey of Health and Development [NSHD], Southall and Brent Revised [SABRE], and UK Biobank) and one younger age cohort (Avon Longitudinal Study of Parents and Children [ALSPAC]), we explored whether APOE ε4 carriage associates with beneficial or unfavorable left ventricular (LV) structural and functional metrics by echocardiography and cardiovascular magnetic resonance (CMR).

RESULTS

Compared to the non-APOE ε4 group, APOE ε4 carriers had similar cardiac phenotypes in terms of LV ejection fraction, E/e', posterior wall and interventricular septal thickness, and LV mass. However, they had improved myocardial performance resulting in greater LV stroke volume generation per 1 mL of myocardium (higher myocardial contraction fraction). In NSHD (n = 1467) and SABRE (n = 1187), ε4 carriers had a 4% higher MCF (95% CI 1-7%, p = 0.016) using echocardiography. Using CMR data, in UK Biobank (n = 32,972), ε4 carriers had a 1% higher MCF 95% (CI 0-1%, p = 0.020) with a dose-response relationship based on the number of ε4 alleles. In addition, UK Biobank ε4 carriers also had more favorable radial and longitudinal strain rates compared to non APOE ε4 carriers. In ALSPAC (n = 1397), APOE ε4 carriers aged < 24 years had a 2% higher MCF (95% CI 0-5%, p = 0.059).

CONCLUSIONS

By triangulating results in four independent cohorts, across imaging modalities (echocardiography and CMR), and in ~ 37,000 individuals, our results point towards an association between ε4 carriage and improved cardiac performance in terms of LV MCF. This potentially favorable cardiac phenotype adds to the growing number of reported survival advantages attributed to the pleiotropic effects APOE ε4 carriage that might collectively explain its persistence in human populations.

APOE and vascular disease: Sequencing and genotyping in general population cohorts

BACKGROUND AND AIMS

The apolipoprotein E(APOE) ϵ2/ϵ3/ϵ4 polymorphism plays a central role in lipid metabolism, vascular disease and dementia. The impact of the full range of structural genetic variation in APOE for lipids, lipoproteins and apolipoproteins and for vascular disease in the general population is not known.

METHODS

We systematically sequenced APOE in 10,296 individuals from the Copenhagen City Heart Study and genotyped nine rare variants (frequency≥2/10,296) in 95,227 individuals from the Copenhagen General Population Study. The UK Biobank was used for validation of common APOE variants.

RESULTS

Rare mutations in APOE, predicted to be deleterious, are present in 1 in 257 individuals in the general population. In the meta-analysis, multifactorially adjusted hazard ratios (95% confidence intervals) for ϵ44 and ϵ22 versus ϵ33 were 1.15 (1.04-1.26) and 1.02 (0.83-1.24) for ischemic cerebrovascular disease (ICVD), 1.11 (1.04-1.19) and 0.94 (0.83-1.08) for ischemic heart disease (IHD) and 1.03 (0.89-1.17) and 1.49 (1.20-1.87) for peripheral arterial disease (PAD). A multifactorially and ϵ2/ϵ3/ϵ4 adjusted weighted allele score on the continuous scale including all common and rare structural variants showed that for individuals with genetically predicted high plasma apoE and remnant cholesterol the risk for PAD was increased.

CONCLUSIONS

APOE variants with high apoE, triglycerides, and remnant cholesterol are associated with PAD, whereas common APOE variants with high LDL cholesterol, triglycerides and remnant cholesterol are associated with IHD. APOE variants with low apoE are associated with increased risk of ICVD. These findings highlight that both rare and common structural variations in APOE play a role in vascular disease.

Apolipoprotein E isoforms differentially affect LCAT-dependent cholesterol esterification

BACKGROUND AND AIMS

LCAT esterifies cholesterol in both HDL (α-activity) and apoB-containing lipoproteins (β-activity). The main activator of LCAT β-activity is apoE, which in humans exists in 3 main different isoforms (E2, E3 and E4). Here, to gather insights into the potential role of LCAT in apoB-containing lipoprotein metabolism, we investigated the ability of apoE isoforms to promote LCAT-mediated cholesterol esterification.

METHODS

We evaluated the plasma cholesterol esterification rate (CER) in 311 individuals who express functional LCAT and either apoE2, apoE3, or apoE4 and in 28 individuals who also carried LCAT mutations causing selective loss of LCAT α-activity (Fish-Eye Disease (FED)-causing mutations). The association of carrier status with CER was determined using an adjusted linear regression model. The kinetic of LCAT activity towards reconstituted HDLs (rHDLs) containing each apoE isoform was determined using the Michaelis-Menten model.

RESULTS

Plasma CER was ∼20% higher in apoE2 carriers compared to apoE3 carriers, and ∼30% higher in apoE2 carriers compared to apoE4 carriers. After adjusting for age, sex, total cholesterol, HDL-C, apoA-I, apoB, chronic kidney disease diagnosis, zygosity, and LCAT concentration, CER remained significantly different among carriers of the three apoE isoforms. The same trend was observed in carriers of FED-causing mutations. rHDLs containing apoE2 were associated with a lower affinity but higher maximal esterification rate, compared to particles containing apoE3 or apoE4.

CONCLUSION

The present results suggest that the apoE2 isoform is associated with a higher LCAT-mediated cholesterol esterification. This observation may contribute to the characterization of the peculiar functional properties of apoE2.

Alteration of Blood Immune Biomarkers in MCI Patients with Different APOE Genotypes after Cognitive Training: A 1 Year Follow-Up Cohort Study

Many studies aim to detect the early phase of dementia. One of the major ways to achieve this is to identify corresponding biomarkers, particularly immune blood biomarkers. The objective of this study was to identify such biomarkers in patients with mild cognitive impairment (MCI) in an experiment that included cognitive training. A group of patients with MCI diagnoses over the age of 65 participated in the study (n = 136). Measurements of cognitive functions (using the Mini-Mental State Examination scale and Montreal Cognitive Assessment) and determination of 27 serum biomarkers were performed twice: on the first visit and on the second visit, one year after the cognitive training. APOE genotypes were also determined. Concentrations of EGF (F = 17; p = 0.00007), Eotaxin (F = 7.17; p = 0.008), GRO (F = 13.42; p = 0.0004), IL-8 (F = 8.16; p = 0.005), MCP-1 (F = 13.46; p = 0.0001) and MDC (F = 5.93; p = 0.016) increased after the cognitive training in MCI patients. All these parameters except IL-8 demonstrated a weak correlation with other immune parameters and were poorly represented in the principal component analysis. Differences in concentrations of IP-10, FGF-2, TGFa and VEGF in patients with MCI were associated with APOE genotype. Therefore, the study identified several immune blood biomarkers that could potentially be associated with changes in cognitive function.

Unraveling Mechanisms of Cryptogenic Stroke at the Genetic Level: A Systematic Literature Review

Background A substantial proportion of ischemic strokes remain cryptogenic, which has important implications for secondary prevention. Identifying genetic variants related to mechanisms of stroke causes may provide a chance to clarify the actual causes of cryptogenic strokes. Methods and Results In a 2-step process, 2 investigators independently and systematically screened studies that reported genetic variants in regard to stroke causes that were published between January 1991 and April 2021. Studies on monogenetic disorders, investigation of vascular risk factors as the primary end point, reviews, meta-analyses, and studies not written in English were excluded. We extracted information on study types, ancestries, corresponding single nucleotide polymorphisms, and sample and effect sizes. There were 937 studies screened, and 233 were eligible. We identified 35 single nucleotide polymorphisms and allele variants that were associated with an overlap between cryptogenic strokes and another defined cause. Conclusions Associations of single variants with an overlap between cryptogenic stroke and another defined cause were limited to a few polymorphisms. A limitation of all studies is a low granularity of clinical data, which is of major importance in a complex disease such as stroke. Deep phenotyping is in supposed contradiction with large sample sizes but needed for genome-wide analyses. Future studies should attempt to address this restriction to advance the promising approach of elucidating the cause of stroke at the genetic level. Especially in a highly heterogenous disease such as ischemic stroke, genetics are promising to establish a personalized approach in diagnostics and treatment in the sense of precision medicine.

AD and non-AD mediators of the pathway between the APOE genotype and cognition

INTRODUCTION

The apolipoprotein E (APOE) genotype is a driver of cognitive decline and dementia. We used causal mediation methods to characterize pathways linking the APOE genotype to late-life cognition through Alzheimer's disease (AD) and non-AD neuropathologies.

METHODS

We analyzed autopsy data from 1671 individuals from the Religious Orders Study, Memory and Aging Project, and Minority Aging Research Study (ROS/MAP/MARS) studies with cognitive assessment within 5 years of death and autopsy measures of AD (amyloid beta (Aβ), neurofibrillary tangles), vascular (athero/arteriolo-sclerosis, micro-infarcts/macro-infarcts), and non-AD neurodegenerative neuropathologies (TAR DNA protein 43 [TDP-43], Lewy bodies, amyloid angiopathy, hippocampal sclerosis).

RESULTS

The detrimental effect of APOE ε4 on cognition was mediated by summary measures of AD and non-AD neurodegenerative neuropathologies but not vascular neuropathologies; effects were strongest in individuals with dementia. The protective effect of APOE ε2 was partly mediated by AD neuropathology and stronger in women than in men.

DISCUSSION

The APOE genotype influences cognition and dementia through multiple neuropathological pathways, with implications for different therapeutic strategies targeting people at increased risk for dementia.

HIGHLIGHTS

Both apolipoprotein E (APOE) ε2 and APOE ε4 effects on late-life cognition are mediated by AD neuropathology. The estimated mediated effects of most measures of AD neuropathology were similar. Non-Alzheimer's disease (AD) neurodegenerative pathologies mediate the effect of ε4 independently from AD. Non-AD vascular pathologies did not mediate the effect of the APOE genotype on cognition. The protective effect of APOE ε2 on cognition was stronger in women.

Predictive Factors and Interventional Modalities of Post-stroke Motor Recovery: An Overview

Stroke is the most common cause of motor impairment worldwide. Therefore, many factors are being investigated for their predictive and facilitatory effects on recovery of motor function after stroke. Motor recovery can be predicted through several factors, such as clinical assessment, clinical biomarkers, and gene-based variations. As for interventions, many methods are under experimental investigation that aim to improve motor recovery, including different types of pharmacological interventions, non-invasive stimulation, and rehabilitation training by inducing cortical reorganization, neuroplasticity, angiogenesis, changing the levels of neurotransmitters in the brain, and altering the inflammatory and apoptotic processes occurring after stroke. Studies have shown that clinical biomarkers combined with clinical assessment and gene-based variations are reliable factors for predicting motor recovery after stroke. Moreover, different types of interventions such as pharmacological agents (selective serotonin reuptake inhibitors {SSRI}, noradrenaline reuptake inhibitors {NARIs}, levodopa, and amphetamine), non-invasive stimulation, and rehabilitation training have shown significant results in improving functional and motor recovery.

Genome-wide genotype-serum proteome mapping provides insights into the cross-ancestry differences in cardiometabolic disease susceptibility

Identification of protein quantitative trait loci (pQTL) helps understand the underlying mechanisms of diseases and discover promising targets for pharmacological intervention. For most important class of drug targets, genetic evidence needs to be generalizable to diverse populations. Given that the majority of the previous studies were conducted in European ancestry populations, little is known about the protein-associated genetic variants in East Asians. Based on data-independent acquisition mass spectrometry technique, we conduct genome-wide association analyses for 304 unique proteins in 2,958 Han Chinese participants. We identify 195 genetic variant-protein associations. Colocalization and Mendelian randomization analyses highlight 60 gene-protein-phenotype associations, 45 of which (75%) have not been prioritized in Europeans previously. Further cross-ancestry analyses uncover key proteins that contributed to the differences in the obesity-induced diabetes and coronary artery disease susceptibility. These findings provide novel druggable proteins as well as a unique resource for the trans-ancestry evaluation of protein-targeted drug discovery.

Associations of Alzheimer Disease-Protective APOE Variants With Age-Related Macular Degeneration

Importance

The association of major lipid genes with and their potential as drug targets for age-related macular degeneration (AMD) is unknown. These associations are important to study because AMD is the leading cause of irreversible late-onset blindness in high-income countries.

Objective

To determine whether the full range of structural genetic variation in apolipoprotein E (APOE), a master gene in peripheral and cerebral lipid metabolism, is associated with risk of AMD.

Design, Setting, and Participants

This cohort study used data from the Copenhagen City Heart Study (CCHS) and the Copenhagen General Population Study (CGPS) cohorts. Participants were followed from study inclusion at the time of blood sampling to occurrence of event, death, emigration, or December 7, 2018, whichever came first. For participants in CCHS, the APOE gene was sequenced, and 9 variants with a heterozygote frequency of at least 0.0002 were genotyped in the CGPS. Observers were masked to patient groupings. Data were analyzed from March to September 2021.

Exposures

The exposure was APOE status, and the direct gene product in plasma, apoE levels, was measured in all participants.

Main Outcomes and Measures

Cox regression was applied to estimate risk of AMD associated with APOE genotype.

Results

A total of 105 546 participants (mean [SD] age, 57.7 [13.4] years; 58 140 [55%] female participants) were included. Compared with participants with the common ɛ33 genotype, risk of AMD was lower in participants with ε44 (multifactorially adjusted hazard ratio [aHR], 0.66; 95% CI, 0.45-0.96) and ε43 (aHR, 0.80; 95% CI, 0.71-0.90) genotypes and higher in the ε32 (aHR, 1.15; 95% CI, 1.00-1.31) genotype. Compared with noncarriers, risk of AMD was higher for participants with Gly145Asp (aHR, 3.53; 95% CI, 1.14-10.96) and Arg154Cys (aHR, 4.52; 95% CI, 1-13-18.13) heterozygotes. Results were similar after further adjustment for lipid traits and after adjustment for the APOE ε2/ε3/ε4 variant. Combining all common and rare structural variants in a weighted allele score, risk of AMD per 1-mg/dL genetically higher plasma apoE was increased in the adjusted model (aHR, 1.12; 95% CI, 1.05-1.19), the adjusted model plus APOE ɛ2/ɛ3/ɛ4 status (aHR, 1.82; 95% CI, 1.20-2.76), and the adjusted model in individuals with the ε33 genotype only (aHR, 1.77; 95% CI, 1.14-2.75).

Conclusions and Relevance

These findings highlight that structural variation in APOE beyond the ε2/ε3/ε4 variants may be important for risk of AMD in a population of European ancestry. Rare functional ɛ2-like variants in APOE have previously been reported to have protective associations for Alzheimer disease but the present findings suggest a simultaneous high risk of AMD. This would limit the drug target potential of mechanisms resembling these variants.

Polygenic Liability to Alzheimer's Disease Is Associated with a Wide Range of Chronic Diseases: A Cohort Study of 312,305 Participants

BACKGROUND

Alzheimer's disease (AD) patients rank among the highest levels of comorbidities compared to persons with other diseases. However, it is unclear whether the conditions are caused by shared pathophysiology due to the genetic pleiotropy for AD risk genes.

OBJECTIVE

To figure out the genetic pleiotropy for AD risk genes in a wide range of diseases.

METHODS

We estimated the polygenic risk score (PRS) for AD and tested the association between PRS and 16 ICD10 main chapters, 136 ICD10 level-1 chapters, and 377 diseases with cases more than 1,000 in 312,305 individuals without AD diagnosis from the UK Biobank.

RESULTS

After correction for multiple testing, AD PRS was associated with two main ICD10 chapters: Chapter IV (endocrine, nutritional and metabolic diseases) and Chapter VII (eye and adnexa disorders). When narrowing the definition of the phenotypes, positive associations were observed between AD PRS and other types of dementia (OR = 1.39, 95% CI [1.34, 1.45], p = 1.96E-59) and other degenerative diseases of the nervous system (OR = 1.18, 95% CI [1.13, 1.24], p = 7.74E-10). In contrast, we detected negative associations between AD PRS and diabetes mellitus, obesity, chronic bronchitis, other retinal disorders, pancreas diseases, and cholecystitis without cholelithiasis (ORs range from 0.94 to 0.97, FDR < 0.05).

CONCLUSION

Our study confirms several associations reported previously and finds some novel results, which extends the knowledge of genetic pleiotropy for AD in a range of diseases. Further mechanistic studies are necessary to illustrate the molecular mechanisms behind these associations.

The Unstable Carotid Plaque

Carotid revascularization is performed to prevent cerebrovascular events in patients with symptomatic (>50%) and asymptomatic high degree (>70%) carotid stenosis. As this operation carries significant risks for perioperative stroke, careful selection of patients who will benefit from the procedure is essential. Certain plaque characteristics, including texture, are associated with increased tendency for rupture and can be used to identify high-risk patients. Medical therapy, carotid endarterectomy, and carotid stenting are the mainstays for patient management. With careful selection of patients, all anesthesia techniques (general anesthesia, monitored anesthesia care, and regional anesthesia) can be used safely for these revascularization procedures.

Transcriptomic analysis identifies shared biological foundations between ischemic stroke and Alzheimer's disease

AIM

Alzheimer's disease (AD) and ischemic stroke (IS), two major neurological diseases, are suggested to be associated in clinical and pathophysiological levels. Previous studies have provided some insights into the possible genetic mechanisms behind the correlation between AD and IS, but this issue is still not clear. We implemented transcriptomic analysis to detect common hub genes and pathways to help promote the understanding of this issue.

MATERIALS AND METHODS

Four gene expression profiling datasets (GSE16561, GSE58294, GSE63060, and GSE63061) of peripheral whole blood, which contain 108 IS samples, 284 AD samples, and 285 matched controls, were employed to detect differentially expressed genes (DEGs) for AD and IS, which were further analyzed for shared biological pathways, candidate drugs, and transcription factors. Protein-protein interaction (PPI) network and drug-target interaction analysis were applied to identify hub genes and drug targets, respectively. Result verification was done with other independent datasets (GSE37587, GSE46480, and GSE140829). The difference in proportions of various immune cells in the peripheral blood of AD and IS patients were evaluated using CIBERSORT.

RESULTS

We identified 74 DEGs and 18 biological processes with statistical significance shared by AD and IS, 9 of which were immune-related pathways. Five hub genes scored high in the topological analysis of the PPI network, and we also found eight drug target genes and candidate drugs which were associated with AD and IS. As for immunological changes, an increase in the proportion of M0 macrophages was found in the peripheral circulation of both AD and IS patients, and SOD1 expression was significantly correlated with this change.

CONCLUSION

Collectively, the common DEGs and shared pathways found in this study suggest a potential shared etiology between AD and IS, behind which immune system, particularly the M0 macrophage elevation, might have important roles. While, the shared hub genes, potential therapeutic gene targets and drugs reported in this study provide promising treatment strategies for AD and IS.

Cardiorespiratory fitness decreases the odds for subclinical carotid plaques in apolipoprotein e4 homozygotes

Some studies suggest that being an apolipoprotein e4 (APOE e4) carrier increases the risk of atherosclerosis, and others suggest that cardiorespiratory fitness (CRF) could play a key role in atherosclerotic prevention. Our aim was to analyze the association of APOE e4 with carotid atherosclerosis and the association of CRF with atherosclerosis in APOE e4 carriers. A cross-sectional analysis based on a subsample of 90 participants in the Aragon Workers' Health Study was carried out. Ultrasonography was used to assess the presence of plaques in carotid territory; the submaximal Chester Step Test was used to assess CRF; and behavioral, demographic, anthropometric, and clinical data were obtained by trained personnel during annual medical examinations. APOE e4e4 participants were categorized into Low-CRF (VO_2max < 35 mL/kg/min) and High-CRF (VO_2max ≥ 35 mL/kg/min) groups. After adjusting for several confounders, compared with APOE e3e3, those participants genotyped as APOE e3e4 and APOE e4e4 showed an OR = 1.60 (95% CI 0.45, 5.71) and OR = 4.29 (95% CI 1.16, 15.91), respectively, for carotid atherosclerosis. Compared to Low-CRF APOE e4e4 carriers, the odds of carotid plaque detection were 0.09 (95% CI 0.008, 0.98) times lower among High-CRF APOE e4e4 carriers. The APOE e4e4 genotype was associated with increased carotid atherosclerosis. However, CRF is a modifiable factor that may be targeted by APOE e4e4 to decrease the elevation of atherosclerotic risk due to this genetic condition.

Association between APOE Genotype with Body Composition and Cardiovascular Disease Risk Markers Is Modulated by BMI in Healthy Adults: Findings from the BODYCON Study

Body mass index (BMI) has been suggested to play an important role in the relationship between the APOLIPOPROTEIN (APO)E genotype and cardiovascular disease (CVD) risk. Using data from the BODYCON cross-sectional study (n = 360 adults) we assessed the association between body composition and CVD risk markers according to APOE genotype, with examination of the role of BMI. In this study cohort, the APOE2/E3 group had lower fasting blood lipids than APOE4 carriers and APOE3/E3 group (p ≤ 0.01). After stratifying the group according to BMI, APOE4 carriers in the normal BMI subgroup had a higher lean mass compared with the APOE3/E3 group (p = 0.02) whereas in the overweight/obese subgroup, the android to gynoid percentage fat ratio was lower in APOE4 carriers than APOE3/E3 group (p = 0.04). Fasting lipid concentrations were only different between the APOE2/E3 and other genotype groups within the normal weight BMI subgroup (p ≤ 0.04). This finding was associated with a lower dietary fibre and a higher trans-fat intake compared with APOE4 carriers, and a lower carbohydrate intake relative to the APOE3/E3 group. Our results confirm previous reports that BMI modulates the effect of APOE on CVD risk markers and suggest novel interactions on body composition, with diet a potential modulator of this relationship.

The causes and consequences of Alzheimer's disease: phenome-wide evidence from Mendelian randomization

Alzheimer's disease (AD) has no proven causal and modifiable risk factors, or effective interventions. We report a phenome-wide association study (PheWAS) of genetic liability for AD in 334,968 participants of the UK Biobank study, stratified by age. We also examined the effects of AD genetic liability on previously implicated risk factors. We replicated these analyses in the HUNT study. PheWAS hits and previously implicated risk factors were followed up in a Mendelian randomization (MR) framework to identify the causal effect of each risk factor on AD risk. A higher genetic liability for AD was associated with medical history and cognitive, lifestyle, physical and blood-based measures as early as 39 years of age. These effects were largely driven by the APOE gene. The follow-up MR analyses were primarily null, implying that most of these associations are likely to be a consequence of prodromal disease or selection bias, rather than the risk factor causing the disease.

Urinary Proteome Analysis of Global Cerebral Ischemia-Reperfusion Injury Rat Model via Data-Independent Acquisition and Parallel Reaction Monitoring Proteomics

Cerebral ischemia–reperfusion (I/R) injury is the leading cause of death in severe hypotension caused by cardiac arrest, drowning, and excessive blood loss. Urine can sensitively reflect pathophysiological changes in the brain even at an early stage. In this study, a rat model of global cerebral I/R injury was established via Pulsinelli’s four-vessel occlusion (4-VO) method. Overall, 164 urinary proteins significantly changed in the 4-VO rat urine samples compared to the control samples by data-independent acquisition (DIA) proteomics technique (1.5-fold change, p < 0.05). Gene Ontology annotation showed that the acute-phase response, the ERK1 and ERK2 cascade, endopeptidase activity, blood coagulation, and angiogenesis were overrepresented. After parallel reaction monitoring (PRM) validation, 15 differential proteins having human orthologs were verified as the potential urinary markers associated with cerebral I/R injury. Of these potential biomarkers, 8 proteins were reported to be closely associated with cerebral I/R injury. Nine differential proteins changed even when there were no clinical manifestations or histopathological cerebral damage, including FGG, COMP, TFF2, HG2A, KNG1, CATZ, PTGDS, PRVA, and HEPC. These 9 proteins are potential biomarkers for early screening of cerebral I/R injury to prevent the development of cerebral injury. KNG1, CATZ, PTGDS, PRVA, and HEPC showed an overall trend of upregulation or downregulation at 12 and 48 h after I/R injury, reflecting the progression of cerebral I/R injury. These 5 proteins may serve as potential biomarkers for prognostic evaluation of cerebral I/R injury. These findings provide important clues to inform the monitoring of cerebral I/R injury and further the current understanding of its molecular biological mechanisms.

Dementia risk and dynamic response to exercise: A non-randomized clinical trial

Background

Physical exercise may support brain health and cognition over the course of typical aging. The goal of this nonrandomized clinical trial was to examine the effect of an acute bout of aerobic exercise on brain blood flow and blood neurotrophic factors associated with exercise response and brain function in older adults with and without possession of the Apolipoprotein epsilon 4 (APOE4) allele, a genetic risk factor for developing Alzheimer’s. We hypothesized that older adult APOE4 carriers would have lower cerebral blood flow regulation and would demonstrate blunted neurotrophic response to exercise compared to noncarriers.

Methods

Sixty-two older adults (73±5 years old, 41 female [67%]) consented to this prospectively enrolling clinical trial, utilizing a single arm, single visit, experimental design, with post-hoc assessment of difference in outcomes based on APOE4 carriership. All participants completed a single 15-minute bout of moderate-intensity aerobic exercise. The primary outcome measure was change in cortical gray matter cerebral blood flow in cortical gray matter measured by magnetic resonance imaging (MRI) arterial spin labeling (ASL), defined as the total perfusion (area under the curve, AUC) following exercise. Secondary outcomes were changes in blood neurotrophin concentrations of insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF), and brain derived neurotrophic factor (BDNF).

Results

Genotyping failed in one individual (n = 23 APOE4 carriers and n = 38 APOE4 non-carriers) and two participants could not complete primary outcome testing. Cerebral blood flow AUC increased immediately following exercise, regardless of APOE4 carrier status. In an exploratory regional analyses, we found that cerebral blood flow increased in hippocampal brain regions, while showing no change in cerebellum across both groups. Among high inter-individual variability, there were no significant changes in any of the 3 neurotrophic factors for either group immediately following exercise.

Conclusions

Our findings show that both APOE4 carriers and non-carriers show similar effects of exercise-induced increases in cerebral blood flow and neurotrophic response to acute aerobic exercise. Our results provide further evidence that acute exercise-induced increases in cerebral blood flow may be regional specific, and that exercise-induced neurotrophin release may show a differential effect in the aging cardiovascular system. Results from this study provide an initial characterization of the acute brain blood flow and neurotrophin responses to a bout of exercise in older adults with and without this known risk allele for cardiovascular disease and Alzheimer’s disease.

Trial registration

Dementia Risk and Dynamic Response to Exercise (DYNAMIC); Identifier: NCT04009629.

Simultaneous Mass Spectrometry-Based Apolipoprotein Profiling and Apolipoprotein E Phenotyping in Patients with ASCVD and Mild Cognitive Impairment

Apolipoprotein E (apoE) occurs on the majority of plasma lipoproteins and plays a major role in the lipid metabolism in the periphery and in the central nervous system. ApoE is a polymorphic protein with three common isoforms, apoE2, apoE3 and apoE4, derived from respective alleles ε2, ε3 and ε4. The aim of this study was to develop a sample pretreatment protocol combined with rapid mass spectrometry (MS)-based assay for simultaneous apolipoprotein profiling and apoE phenotype identification. This assay was validated in 481 samples from patients with stable atherosclerotic cardiovascular disease (ASCVD) and applied to study association with mild cognitive impairment (MCI) in the LIFE Adult study, including overall 690 study subjects. Simultaneous quantification of 8−12 major apolipoproteins including apoA-I, apoB-100 and apoE could be performed within 6.5 min. Phenotyping determined with the developed MS assay had good agreement with the genotyping by real-time fluorescence PCR (97.5%). ApoE2 isoform was associated with the highest total apoE concentration compared to apoE3 and apoE4 (p < 0.001). In the subgroup of diabetic atherosclerotic cardiovascular disease (ASCVD) patients, apoE2 isoform was related to higher apoC-I levels (apoE2 vs. apoE3, p < 0.05), while in the subgroup of ASCVD patients under statin therapy apoE2 was related to lower apoB-100 levels (apoE2 vs. apoE3/apoE4, p < 0.05). A significant difference in apoE concentration observed between mild cognitive impairment (MCI) subjects and controls was confirmed for each apoE phenotype. In conclusion, this study provides evidence for the successful implementation of an MS-based apoE phenotyping assay, which can be used to assess phenotype effects on plasma lipid and apolipoprotein levels.

APOE ε4 and late-life cognition: mediation by structural brain imaging markers

The apolipoprotein E allele 4 (APOE-ε4) is established as a major genetic risk factor for cognitive decline and late-onset Alzheimer's disease. Accumulating evidence has linked ε4 carriership to abnormal structural brain changes across the adult lifespan. To better understand the underlying causal mechanisms, we investigated the extent to which the effect of the ε4 allele on cognition is mediated by structural brain imaging markers in the population-based Age, Gene/Environment Susceptibility-Reykjavik Study (AGES-Reykjavik). This study included 4527 participants (aged 76.3 ± 5.4 at baseline) who underwent the brain magnetic resonance imaging assessment (of brain tissue volumes, white matter lesion volume, subcortical and cortical infarcts, and cerebral microbleeds) and a battery of neuropsychological tests at baseline. Causal mediation analysis was used to quantify the mediation of the ε4 effect on cognition by these MRI markers, both individually and jointly. We observed that about 9% of the total effect of ε4 carriership on cognition was mediated by white matter lesion volume. This proportion increased to 25% when total brain tissue volume was jointly considered with white matter lesion volume. In analyses separating ε4 homozygotes from ε4 heterozygotes, the effect on global cognition of specifically ε4 homozygosity appeared to be partially mediated by cerebral microbleeds, particularly lobar microbleeds. There was no evidence of mediation of the ε4 effect by cortical or subcortical infarcts. This study shows that the ε4 effect on cognition is partly mediated by white matter lesion volume and total brain tissue volume. These findings suggest the joint role of cerebral small vessel disease and neurodegeneration in the ε4-cognition relationship.

Egg and cholesterol intake, apolipoprotein E4 phenotype and risk of venous thromboembolism: findings from a prospective cohort study

The impact of egg consumption, a major source of dietary cholesterol, with the risk of atherosclerotic cardiovascular diseases (ASCVDs) is controversial. Venous thromboembolism (VTE) is a CVD which shares common risk factors and mechanistic pathways with ASCVD. However, there is no data on the relationship between egg or cholesterol intake and VTE risk. Therefore, we evaluated the prospective associations of egg and cholesterol intakes with VTE risk and whether the apolipoprotein E4 (apoE4) phenotype, which influences cholesterol metabolism, could modify the associations. Data involving 1,852 men aged 42-61 years at baseline without a history of VTE or coronary heart disease in the population-based Kuopio Ischaemic Heart Disease Risk Factor Study were analysed. Dietary intakes were assessed with 4-day food records. Incident VTE events were identified by record linkage to hospital discharge registries. Hazard ratios (95% confidence intervals [CIs]) for incident VTE were estimated using Cox regression. During a median follow-up of 28.8 years, 132 VTE events occurred. Comparing the top (>38 g/d) versus bottom (<20 g/d) tertiles of egg consumption, the HR (95% CI) for VTE was 0.99 (0.64-1.53) in analysis adjusted for several established risk factors and other dietary factors. There was also no evidence of an association between cholesterol intake and VTE risk. Imputed results were consistent with the observed results. The apoE4 phenotype did not modify the associations. In middle-aged and older Finnish men, egg or cholesterol intakes were not associated with future VTE risk. Other large-scale prospective studies are needed to confirm or refute these findings.

Genetic and Mechanistic Insights into the Modulation of Circulating Lipoprotein (a) Concentration by Apolipoprotein E Isoforms

PURPOSE OF REVIEW

Lipoprotein (a) [Lp(a)] is a highly atherogenic lipoprotein species. A unique feature of Lp(a) is the strong genetic determination of its concentration. The LPA gene is responsible for up to 90% of the variance in Lp(a), but other genes also have an impact.

RECENT FINDINGS

Genome-wide associations studies indicate that the APOE gene, encoding apolipoprotein E (apoE), is the second most important locus modulating Lp(a) concentrations. Population studies clearly show that carriers of the apoE2 variant (ε2) display reduced Lp(a) levels, the lowest concentrations being observed in ε2/ε2 homozygotes. This genotype can lead predisposed adults to develop dysbetalipoproteinemia, a lipid disorder characterized by sharp elevations in cholesterol and triglycerides. However, dysbetalipoproteinemia does not significantly modulate circulating Lp(a). Mechanistically, apoE appears to impair the production but not the catabolism of Lp(a). These observations underline the complexity of Lp(a) metabolism and provide key insights into the pathways governing Lp(a) synthesis and secretion.

Effects of Apolipoprotein E polymorphism on carotid intima-media thickness, incident myocardial infarction and incident stroke

The Apolipoprotein E (APOE) gene polymorphism (rs429358 and rs7412) shows a well-established association with lipid profiles, but its effect on cardiovascular disease is still conflicting. Therefore, we examined the association of different APOE alleles with common carotid artery intima-media thickness (CCA-IMT), carotid plaques, incident myocardial infarction (MI) and stroke. We analyzed data from 3327 participants aged 20-79 years of the population-based Study of Health in Pomerania (SHIP) from Northeast Germany with a median follow-up time of 14.5 years. Linear, logistic, and Cox-regression models were used to assess the associations of the APOE polymorphism with CCA-IMT, carotid plaques, incident MI and stroke, respectively. In our study, the APOE E2 allele was associated with lower CCA-IMT at baseline compared to E3 homozygotes (β: - 0.02 [95% CI - 0.04, - 0.004]). Over the follow-up, 244 MI events and 218 stroke events were observed. APOE E2 and E4 allele were not associated with incident MI (E2 HR: 1.06 [95% CI 0.68, 1.66]; E4 HR: 1.03 [95% CI 0.73, 1.45]) and incident stroke (E2 HR: 0.79 [95% CI 0.48, 1.30]; E4 HR: 0.96 [95% CI 0.66, 1.38]) in any of the models adjusting for potential confounders. However, the positive association between CCA-IMT and incident MI was more pronounced in E2 carriers than E3 homozygotes. Thus, our study suggests that while APOE E2 allele may predispose individuals to lower CCA-IMT, E2 carriers may be more prone to MI than E3 homozygotes as the CCA-IMT increases. APOE E4 allele had no effect on CCA-IMT, plaques, MI or stroke.

Longitudinal association of Apolipoprotein E polymorphism with lipid profile, type 2 diabetes and metabolic syndrome: Results from a 15 year follow-up study

AIMS

To examine the association of different APOE alleles with type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) as well as the influence of high-sensitive C-reactive protein (hs-CRP) on these associations.

METHODS

We analyzed data from 3917 participants aged 20-81 years of the population-based Study of Health in Pomerania (SHIP) from Northeast Germany with a median follow-up time of 10.8 years. Linear and logistic mixed models were performed to test the association of APOE alleles with T2DM and MetS.

RESULTS

We observed 393 T2DM and 1411 MetS events at baseline, and 576 T2DM and 1342 MetS events over the follow-up. The E4 carriers had a lower odds of developing T2DM (OR: 0.47 [0.24, 0.94]) than E3 homozygotes even after adjustment for potential confounders. The E2 carriers showed no associations. The inverse association between E4 alleles and T2DM moderately attenuated after adjustment for hs-CRP levels. The lower odds of developing T2DM in E4 carriers was more pronounced in participants without obesity, hypertension or MetS. However, both E2 and E4 carriers had higher odds of developing MetS (E2 OR: 1.45 [1.03, 2.03]; E4 OR: 1.56 [1.17, 2.09]) than E3 homozygotes.

CONCLUSIONS

While the presence of APOE E4 allele might increase the chance of MetS through its major action on lipids, E4 allele might offer a protection towards T2DM through its influence on inflammation.

Interaction between arteriosclerosis and the APOE4 gene in cognitive decline in older adults: a cross-sectional study in rural minority areas in western China

BACKGROUND

Numerous studies have confirmed that the apolipoprotein E4 allele (APOE4) gene and arteriosclerosis (AS) have a combined effect on the occurrence of cognitive function impairment, and dyslipidaemia levels are significantly correlated with APOE4 levels and AS. Few studies have focused on the combined effect of the APOE4 gene and AS on cognitive function. Therefore, this study aimed to investigate the effect of APOE4 gene and AS acting together on cognitive function through dyslipidaemia levels, which could provide certain scientific research value for future studies.

METHODS

A multi-stage cluster sampling method was used to investigate older adults aged 60 years and above in rural areas of Guizhou, China. The demographic sociological characteristics were collected, and laboratory tests, blood lipid measurements, and physical examinations were performed. Mini-Mental State Examination (MMSE) was used to determine cognitive function. Analysis of variance with two-factor factorial design was used to analyse the interaction between the APOE4 gene and AS on cognitive function and its domains.

RESULTS

A total of 549 elderly subjects were eligible for this study. The result of the factorial design analysis revealed there was a significant interaction between the APOE4 gene and AS in terms of attention and numeracy (F = 6.878, P = 0.009).

CONCLUSIONS

The combination of the APOE4 gene and AS leads to a decrease in the level of attention and numeracy domains, and certain attention should be focused on such populations in the future.

Apolipoprotein E ε4 Polymorphism as a Risk Factor for Ischemic Stroke: A Systematic Review and Meta-Analysis

Introduction

Rising studies indicate that the apolipoprotein E (APOE) gene is related to the susceptibility of ischemic stroke (IS). However, certain consensus is limited by the lack of a large sample size of researches. This meta-analysis was performed to explore the potential association between the APOE gene and IS.

Methods

To identify relevant case control studies in English publications by October 2020, we searched PubMed, Embase, Web of Science, and the Cochrane Library. Pooled odds ratios (ORs) with fixed- or random-effect models and corresponding 95% confidence intervals (CIs) were calculated to analyze potential associations.

Results

A total of 55 researches from 32 countries containing 12207 IS cases and 27742 controls were included. The association between APOE gene ε4 mutation and IS was confirmed (ε4 vs. ε3 allele: pooled OR = 1.374, 95% CI, 1.214-1.556; ε2/ε4 vs. ε3/ε3: pooled OR = 1.233, 95% CI, 1.056-1.440; ε3/ε4 vs. ε3/ε3: pooled OR = 1.340, 95% CI, 1.165-1.542; ε4/ε4 vs. ε3/ε3: pooled OR = 1.833, 95% CI, 1.542-2.179; and APOE ε4 carriers vs. non-ε4 carriers: pooled OR = 1.377; 95% CI, 1.203-1.576). Interestingly, APOE ε4 mutation showed a dose-response correlation with IS risk (ε4/ε4 vs. ε2/ε4: pooled OR = 1.625; 95% CI, 1.281-2.060; ε4/ε4 vs. ε3/ε4: pooled OR = 1.301; 95% CI, 1.077-1.571). Similar conclusions were drawn in the small artery disease (SAD) subtype, but not in large artery atherosclerosis (LAA) or in cardioaortic embolism (CE), by subgroup analysis.

Conclusions

These observations reveal that specific APOE ε4 mutation was significantly associated with the risk of IS in a dose-dependent manner, while APOE ε4 mutation was related to SAD subtype onset without a cumulative effect.

Apolipoprotein E Genotype Moderation of the Association Between Physical Activity and Brain Health. A Systematic Review and Meta-Analysis

Introduction

Possession of one or two e4 alleles of the apolipoprotein E (APOE) gene is associated with cognitive decline and dementia risk. Some evidence suggests that physical activity may benefit carriers of the e4 allele differently.

Method

We conducted a systematic review and meta-analysis of studies which assessed APOE differences in the association between physical activity and: lipid profile, Alzheimer's disease pathology, brain structure and brain function in healthy adults. Searches were carried out in PubMed, SCOPUS, Web of Science and PsycInfo.

Results

Thirty studies were included from 4,896 papers screened. Carriers of the e4 allele gained the same benefit from physical activity as non-carriers on most outcomes. For brain activation, e4 carriers appeared to gain a greater benefit from physical activity on task-related and resting-state activation and resting-state functional connectivity compared to non-carriers. Post-hoc analysis identified possible compensatory mechanisms allowing e4 carriers to maintain cognitive function.

Discussion

Though there is evidence suggesting physical activity may benefit e4 carriers differently compared to non-carriers, this may vary by the specific brain health outcome, perhaps limited to brain activation. Further research is required to confirm these findings and elucidate the mechanisms.

Does personalised nutrition advice based on apolipoprotein E and methylenetetrahydrofolate reductase genotype affect dietary behaviour?

Background: Dietary intake is linked to numerous modifiable risk factors of cardiovascular disease. Current dietary recommendations in the UK to reduce the risk of cardiovascular disease are not being met. A genotype-based personalised approach to dietary recommendations may motivate individuals to make positive changes in their dietary behaviour. Aim: To determine the effect of a personalised nutrition intervention, based on apolipoprotein E (ApoE, rs7412; rs429358) and methylenetetrahydrofolate reductase (MTHFR, rs1801133) genotype, on reported dietary intake of saturated fat and folate in participants informed of a risk genotype compared to those informed of non-risk genotype. Methods: Baseline data (n = 99) were collected to determine genotype (non-risk vs risk), dietary intake and cardiovascular risk (Q-Risk®2 cardiovascular risk calculator). Participants were provided with personalised nutrition advice via email based on their ApoE and MTHFR genotype and reported intake of folate and saturated fat. After 10 days, dietary intake data were reported for a second time. Results: Personalised nutrition advice led to favourable dietary changes, irrespective of genotype, in participants who were not meeting dietary recommendations at baseline for saturated fat (p < 0.001) and folate (p = 0.002). Only participants who were informed of a risk ApoE genotype met saturated fat recommendations following personalised nutrition advice. Conclusion: Incorporation of genotype-based personalised nutrition advice in a diet behaviour intervention may elicit favourable changes in dietary behaviour in participants informed of a risk genotype. Participants informed of a non-risk genotype also respond to personalised nutrition advice favourably but to a lesser extent.

Prognostic value of apolipoproteins in COVID-19 patients: A systematic review and meta-analysis

INTRODUCTION

Apolipoproteins are predictive biomarkers for cardiovascular, neoplasms and cerebrovascular diseases and are postulated as prognostic biomarkers in infectious diseases, as COVID-19. Thus, we assessed the prognosis value of apolipoproteins for COVID-19 severity and mortality.

METHODS

We conducted a systematic review and meta-analysis using observational studies that reported the association between apolipoproteins and severity or mortality in COVID-19 patients. Newcastle-Ottawa was used for the quality assessment of included studies. Effects measurements were shown as odds ratios (ORs) with 95% confidence intervals (CIs), and Egger-test was developed for assessing the risk of bias publication.

RESULTS

We analyzed 12 cohort studies (n = 3580). Patients with low ApoliproteinA1 (ApoA1) (OR 0.35; 95%CI 0.24 to 0.49; P < 0.001) and ApoliproteinB (ApoB) (OR = 0.78; 95%CI 0.69 to 0.87; P < 0.001) values had a higher risk of developing severe disease. ApoB/ApoA1 ratio showed no statistically significant association with higher odds of severity. Low ApoA1 levels were associated with higher odds of all-cause mortality (OR = 0.34; 95%CI 0.20 to 0.57; P < 0.001). ApoB values showed no statistically significant association with a high risk of all-cause mortality.

CONCLUSION

We suggest that adequate levels of ApoA1 and ApoB can be a protective factor for severity in COVID-19, and ApoB/ApoA1 ratio did not show predictive utility for severity.

Dogs lacking Apolipoprotein E show advanced atherosclerosis leading to apparent clinical complications

Atherosclerotic cardiovascular disease resulting from dysregulated lipid metabolism is the leading cause of morbidity and mortality worldwide. Apolipoprotein E (ApoE) plays a critical role in cholesterol metabolism. Knockouts in lipid-metabolizing proteins including ApoE in multiple model organisms such as mice and rats exhibiting elevated levels of cholesterol have been widely used for dissecting the pathology of atherosclerosis, but few of these animal models exhibit advanced atherosclerotic plaques leading to ischemia-induced clinical symptoms, limiting their use for translational studies. Here we report hypercholesterolemia and severe atherosclerosis characterized by stenosis and occlusion of arteries, together with clinical manifestations of stroke and gangrene, in ApoE knockout dogs generated by CRISPR/Cas9 and cloned by somatic cell nuclear transfer technologies. Importantly, the hypercholesterolemia and atherosclerotic complications in F0 mutants are recapitulated in their offspring. As the ApoE-associated atherosclerosis and clinical manifestations in mutant dogs are more similar to that in human patients compared with those in other animal models, these mutant dogs will be invaluable in developing and evaluating new therapies, including endovascular procedures, against atherosclerosis and related disorders.

Familial dysbetalipoproteinemia: highly atherogenic and underdiagnosed disorder

Familial dysbetalipoproteinemia (FD) is a genetic, highly atherogenic disorder. The penetrance of FD depends on the patient’s lifestyle and concomitant diseases. Despite the fact that FD was described almost half a century ago, it is still insufficiently studied and is extremely rarely diagnosed. In actual clinical practice, physicians do not have clear understanding of clinical course and genetic basis of FD. The aim was to present the most complete, but at the same time a critical review with a modern view on FD. We analyzed Russian and foreign publications from following electronic databases: PubMed, eLIBRARY, Google Scholar. As a result, the phenotypic features and genetic variability of the disease were considered and the main issues of diagnosis and treatment of patients with FD were discussed. The data presented will help the clinician to timely suspect the FD, conduct a full range of investigations and prescribe evidence-based lipid-lowering therapy.

Single Nucleotide Polymorphisms in Apolipoprotein B, Apolipoprotein E, and Methylenetetrahydrofolate Reductase Are Associated With Serum Lipid Levels in Northern Chilean Subjects. A Pilot Study

Characterization of allelic variants is relevant to demonstrate associations among genetic background and susceptibility to develop cardiovascular diseases, which are the main cause of death in Chile. Association of APOB, APOE, and MTHFR polymorphisms with higher lipid levels and the risk of developing hypertension and cardiovascular diseases have been described. Thus, the aim of this study was to assess genotype distribution and relative allelic frequency of ApoB rs693, ApoE rs7412, ApoE rs429358, MTHFR rs1801131, and MTHFR rs1801133 allelic variants and their effects on lipid profile in young healthy men and women from Northern Chile. A group of 193 healthy subjects were enrolled for this study. Genotyping of rs693 (APOB), rs7412 and rs429358 (APOE), and rs1801131 and rs1801133 (MTHFR) polymorphisms were performed by real time PCR. In addition, lipid profiles were determined and associated to genetic data. The genotype distribution was APOB rs693 (CC = 37%, CT = 41%, and TT = 22%), APOE rs7412/rs429358 (E4 = 0.06, E3 = 0.91, and E2 = 0.03), MTHFR rs1801131 (AA = 57%, AC = 30%, and CC = 13%), and MTHFR rs1801133 (CC = 20%, CT = 47%, and TT = 33%). The association of the genetic variants with plasma lipid levels showed that women, but not men, carrying APOB mutated allele (T) and Apo E4 allele presented lower values of total cholesterol when compared with C/C homozygous genotype or E3 allele, respectively (p < 0.05). In addition, a subgroup analysis revealed that ApoB C/C homozygous women exhibited higher values of HDL-C when compared with men carrying identical genotype (p < 0.01). On the other hand, women carrying E4 allele exhibited lower values of triglycerides when compared with male carrying identical genotype (p < 0.05). Finally, women carrying mutate allele (C) for MTHFR rs1801131 showed lower levels of triglycerides when compared with A/A homozygous genotype (p < 0.05) and lower levels of LDL-C for MTHFR rs1801133 in females carrying (T) allele when compared with males carrying identical genotype (p < 0.05). In summary, the present data showed that APOB, APOE, and MTHFR single nucleotide polymorphisms are associated to lipid levels in a gender-dependent manner among healthy subjects from Northern Chile, especially in women.

Mediation of the APOE associations with Alzheimer's and coronary heart diseases through body mass index and lipids

The APOE ε2/ε3/ε4 polymorphism is associated with multiple non-Mendelian traits, including high- (HDL-C) and low- (LDL-C) density lipoprotein cholesterol, triglycerides, body mass index (BMI), coronary heart disease (CHD), and Alzheimer's disease (AD). Lipids and BMI are risk factors for AD and CHD. Causal connections between the ε2 and ε4 alleles and these traits remain, however, poorly understood. We leverage comprehensive analyses of longitudinal data from four studies to examine potentially causal heterogeneous connections between these alleles, lipids, BMI, and diseases. We emphasize mutual mediation roles of lipids and BMI in their associations with the ε2 and ε4 alleles and their mediation roles in the associations of these alleles with AD and CHD. We confirmed previously reported significant univariate associations of these alleles with each trait, except CHD. We found, however, that most of the univariate- and mediation-analysis associations were affected by antagonistic heterogeneity/mediation. The mutual mediation analysis identified the associations of the APOE alleles with LDL-C as the least heterogeneous. The ε2 and ε4 alleles were associated with CHD through lipids, led by beneficial (β_IE =  - 0.071, p_IE = 2.28 × 10^-10) and adverse (β_IE = 0.019, p_IE = 7.37 × 10^-6) associations, respectively, through LDL-C. Both these alleles were adversely associated with CHD through triglycerides. For AD, only BMI partially mediated the adverse association of the ε4 allele with AD (β_IE = 0.016, p_IE = 2.09 × 10^-2). Our results suggest different roles of BMI and lipids in the AD and CHD pathogeneses. More comprehensive studies of causal connections between genetic variants and non-Mendelian traits are required as they can be critically affected by heterogeneous antagonistic relationships.

Status of biomarkers for the identification of stable or vulnerable plaques in atherosclerosis

Atherosclerosis is a systemic inflammation of the arteries characterized by atherosclerotic plaque due to the accumulation of lipids, inflammatory cells, apoptotic cells, calcium and extracellular matrix (ECM) proteins. Stable plaques present a chronic inflammatory infiltration, whereas vulnerable plaques present an 'active' inflammation involved in the thinning of the fibrous cap that predisposes to plaque rupture. Several complex biological cellular processes lead plaques to evolve from stable to vulnerable predisposing them to rupture and thrombosis. In this review, we analyze some emerging circulating biomarkers related to inflammation, ECM and lipid infiltration, angiogenesis, metalloproteinases and microRNA (miRNA), as possible diagnostic and prognostic indicators of plaque vulnerability.

Analysis of the Potential Genetic Links between Psoriasis and Cardiovascular Risk Factors

Cardiovascular risk factors are one of the most common comorbidities in psoriasis. A higher prevalence of hypertension, insulin resistance and type 2 diabetes, dyslipidemia, obesity, metabolic syndrome, depression, as well as cardiovascular disease was confirmed in psoriatic patients in comparison to the general population. Data suggest that psoriasis and systemic inflammatory disorders may originate from the pleiotropic interactions with many genetic pathways. In this review, the authors present the current state of knowledge on the potential genetic links between psoriasis and cardiovascular risk factors. The understanding of the processes linking psoriasis with cardiovascular risk factors can lead to improvement of psoriasis management in the future.

Can Physical Activity Reduce the Risk of Cognitive Decline in Apolipoprotein e4 Carriers? A Systematic Review

Physical activity (PA) reduces the risk of cognitive decline (CD) in the general population. However, little is known about whether the presence of the apolipoprotein E epsilon 4 allele (APOE e4) could modify this beneficial effect. The aim of this systematic review was to analyze and synthetize the scientific evidence related to PA levels and CD risk in cognitively healthy APOE e4 carriers. Four electronic databases were analyzed. Only original articles with longitudinal study design were selected to analyze the relationship between PA and CD in APOE e4 carriers. Five studies were included in the systematic review. All studies except one stated that PA is a protective factor against CD in APOE e4 carriers. Moreover, partial support was found for the hypothesis that a greater amount and intensity of PA are more beneficial in CD prevention. The results support the idea that PA is a protective factor against CD in APOE e4 carriers. Nevertheless, it would be necessary to carry out further studies that would allow these findings to be contrasted.

Global research trends of Apolipoprotein E in central nervous system: A scientometric analysis

Apolipoprotein E (apoE, protein; APOE, gene) involves in cholesterol recycling and redistribution by mediating lipoprotein pathways unique to central nervous system (CNS), which is a potential therapeutic target for diseases. We visually analyzed the research hotspots of APOE related to CNS in this work, by scientometric analysis from the Web of Science Core Collection (WOSCC) database over the past two decades. A total of 25,719 references of "APOE" and 836 references of "APOE in CNS" were retrieved from the WOSCC on October 26, 2020, and then VOSviewer 1.6.15, Citespace 5.7.R2 were used for visual analysis. Over the last two decades, the research on the field of APOE in CNS is not faddish. Although many funds, organizations, and scholars were affiliated in this field, organizations and scholars, especially the top teams in this field, still lacked close cooperation with other teams around the world. Few articles with high citations had been published in the last decade, but recent studies still lacked scale and breakthrough, and the keywords associated with APOE appeared more outdated. However, the current researches have not fully elucidated the crosstalk between APOE and neuroinflammation in CNS, some new ideas may rekindle the research enthusiasm of scholars. Although the field of APOE in CNS appeared more outdated. Based on keyword analysis, we hypothesized new ideas for further investigation of neuroinflammation would light the interest of APOE in CNS for the scholars. The crosstalk between ApoE and inflammasome may be the focus of future researches. How APOE modulates the time course or intensity of the inflammasome activation, inflammatory response (proinflammatory or anti-inflammatory), and pathological process of CNS disease deserves future attention in both basic and clinical studies. More apoE/APOE-targeted pharmacological interventions will be available for preclinical experiments and clinical trials and bring hope for patients with CNS diseases.

Investigating Effects of Plasma Apolipoprotein E on Ischemic Heart Disease Using Mendelian Randomization Study

BACKGROUND

Observationally plasma apolipoprotein E (apoE) is positively associated with ischemic heart disease (IHD). A Mendelian randomization (MR) study suggesting apoE is unrelated to cardiovascular mortality did not consider specific isoforms. We used MR to obtain estimates of plasma apoE2, apoE3 and apoE4 on IHD, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, triglycerides and apolipoprotein B (apoB).

METHODS

We obtained independent genetic instruments from proteome genome-wide association studies (GWAS) and applied them to large outcome GWAS. We used univariable MR to assess the role of each isoform and multivariable MR to assess direct effects.

RESULTS

In univariable MR, apoE4 was positively associated with IHD (odds ratio (OR) 1.05, 95% confidence interval (CI) 1.01 to 1.09), but apoE2 and apoE3 were less clearly associated. Using multivariable MR an association of apoE2 with IHD (OR 1.16, 95% CI 0.98 to 1.38) could not be excluded, and associations of apoE3 and apoE4 with IHD were not obvious. In univariable MR, apoE2 and apoE4 were positively associated with apoB, and a positive association of apoE2 with LDL cholesterol could not be excluded. Using multivariable MR apoE2 was positively associated with LDL cholesterol, and associations with apoB could not be excluded. After adjusting for apoB, no direct effects of apoE isoforms on IHD were evident.

CONCLUSIONS

Plasma apoE2 and apoE4 may play a role in lipid modulation and IHD. Whether apoE could be a potential therapeutic target requires further clarification when larger genetic studies of apoE isoforms are available.

The advances of post-stroke depression: 2021 update

Post-stroke depression (PSD) is one of common and serious sequelae of stroke. Approximately, one in three stroke survivors suffered from depression after stroke. It heavily affected functional rehabilitation, which leaded to poor quality of life. What is worse, it is strongly associated with high mortality. In this review, we aimed to derive a comprehensive and integrated understanding of PSD according to recently published papers and previous classic articles. Based on the considerable number of studies, we found that within 2 years incidence of PSD has a range from 11 to 41%. Many factors contribute to the occurrence of PSD, including the history of depression, stroke severity, lesion location, and so on. Currently, the diagnosis of PSD is mainly based on the DSM guidelines and combined with various depression scales. Unfortunately, we lack a unified mechanism to explain PSD which mechanisms now involve dysregulation of hypothalamic-pituitary-adrenal (HPA) axis, increased inflammatory factors, decreased levels of monoamines, glutamate-mediated excitotoxicity, and abnormal neurotrophic response. At present, both pharmacotherapy and psychological therapies are employed in treating PSD. Although great advance has been made by researchers, there are still a lot of issues need to be addressed. Especially, the mechanism of PSD is not completely clear.

Age and sex specific effects of APOE genotypes on ischemic heart disease and its risk factors in the UK Biobank

APOE genotypes are associated with ischemic heart disease (IHD), several other cardiovascular diseases and dementia. Previous studies have not comprehensively considered all genotypes, especially ε2ε2, nor associations by age and sex, although IHD incidence differs by sex. In the UK Biobank, including 391,992 white British participants, we compared effects of APOE genotypes on IHD and its risk factors. Compared to the ε3ε3 genotype, ε2ε2 was not clearly associated with IHD but was associated with lower plasma apolipoprotein B (apoB). The ε2ε3 genotype conferred lower IHD risk, systolic blood pressure (SBP), pulse pressure and plasma apoB than ε3ε3. ε3ε4 and ε4ε4 conferred higher IHD risk, higher pulse pressure and plasma apoB, but lower glycated haemoglobin (HbA1c) than ε3ε3. The associations by age and sex were fairly similar, except ε2ε2 compared to ε3ε3 was marginally positively associated with IHD in the younger age group and nominally inversely associated with SBP in men. ε3ε4 compared to ε3ε3 was nominally positively associated with SBP in women. APOE genotypes affect IHD risk increasingly from ε2ε3, ε3ε3, ε3ε4 to ε4ε4, with similar patterns for pulse pressure and plasma apoB, but not for diabetes. Associations with blood pressure differed by sex. Greater understanding of products of APOE and their effects might generate targets of intervention.

Post-traumatic stress disorder and its association with stroke and stroke risk factors: A literature review

Stroke is a major cause of mortality and disability globally that has multiple risk factors. A risk factor that has recently gained more attention is post-traumatic stress disorder (PTSD). Literature searches were carried out for updated PTSD information and for the relationship between PTSD and stroke. The review was divided into two sections, one exploring PTSD as an independent risk factor for stroke, with a second concentrating on PTSD's influence on stroke risk factors. The study presents accumulating evidence that shows traumatic stress predicts stroke and is also linked to many major stroke risk factors. The review contributes knowledge to stroke aetiology and acts as a reference for understanding the relationship between PTSD and stroke. The information presented indicates that screening and identification of traumatic experience would be beneficial for directing stroke patients to appropriate psychological and lifestyle interventions. In doing so, the burden of stroke may be reduced worldwide.

APOE ε4 Carriers Have a Greater Propensity to Glycation and sRAGE Which Is Further Influenced by RAGE G82S Polymorphism

APOE ε4 allele is an established risk factor for Alzheimer's disease and hypercholesterolemia. However, its association with metabolic and genetic risk factors related to glycation is not clear. We tested the hypothesis that, apart from high plasma cholesterol, APOE ε4 carriers may also have higher advanced glycation end products (AGEs) and total soluble extracellular domain of RAGE (sRAGE) and that these biomarkers may be modified by the common Gly82Ser (G82S) polymorphism (rs2070600) in the RAGE gene. To test this, we measured these biomarkers in 172 healthy cognitively normal individuals, of which 32 were APOE ε4 carriers and 140 noncarriers. APOE ε4 carriers showed higher levels of cholesterol (p < .001), glyoxal (p < .001), fluorescent AGEs (p < .001), Nε-carboxymethyllysine (p < .001) and sRAGE (p = .018) when compared to noncarriers. Furthermore, sRAGE was also higher in those that did not carry the A allele of the RAGE gene that codes for serine instead of glycine (p = .034). Our study indicates that APOE ε4 carriers have a greater propensity to glycation than noncarriers which may further increase their risk for diabetes and dementia. The increased sRAGE levels in APOE ε4 carriers suggests a defensive response against AGEs that may be further influenced by the RAGE G82S polymorphism.

The Association Between Apolipoprotein E Gene Polymorphism and In-Stent Restenosis After Extracranial and Intracranial Artery Stenting

BACKGROUND AND PURPOSE

Neo-atherosclerosis plays a vital role in the incidence of in-stent restenosis (ISR) after extracranial and intracranial artery stenting, and Apolipoprotein (ApoE) gene polymorphism has been reported to be closely related to the occurrence and development of atherosclerosis. The present study aims to investigate the association between ApoE gene polymorphism and ISR after extracranial and intracranial artery stenting.

METHODS

A total of 169 patients with successful stent implantation were included in this study. ApoE genotypes were obtained during the postoperative follow-up. Color Doppler ultrasonography of cervical artery or head and neck CT angiography (CTA) was performed on the 1,3,6 and 12 months and then yearly in the clinical follow-up. Multivariate Cox regression analysis of independent risk factors was performed to evaluate the ISR. Kaplan-Meier curves were generated to compare the restenosis -free rate among the patients with different ApoE genotypes.

RESULTS

Of the 169 patients, 43 (43/169, 25.4%) developed ISR after a mean follow-up period of 10.4 months (1-35 months). Multivariate analysis showed that genotype E4/E4 (hazard ratio 3.305, P = 0.031, 95% confidence interval 1.118-9.773) and degree of stenosis >90% (hazard ratio 5.083, P = 0.001, 95% confidence interval 1.938-13.327) were significant determinants of ISR.

CONCLUSION

ApoE gene polymorphism is closely related to the incidence of ISR after extracranial and intracranial artery stenting, and the genotype E4/E4 is an independent risk factor for ISR.

APOE2: protective mechanism and therapeutic implications for Alzheimer's disease

Investigations of apolipoprotein E (APOE) gene, the major genetic risk modifier for Alzheimer's disease (AD), have yielded significant insights into the pathogenic mechanism. Among the three common coding variants, APOE*ε4 increases, whereas APOE*ε2 decreases the risk of late-onset AD compared with APOE*ε3. Despite increased understanding of the detrimental effect of APOE*ε4, it remains unclear how APOE*ε2 confers protection against AD. Accumulating evidence suggests that APOE*ε2 protects against AD through both amyloid-β (Aβ)-dependent and independent mechanisms. In addition, APOE*ε2 has been identified as a longevity gene, suggesting a systemic effect of APOE*ε2 on the aging process. However, APOE*ε2 is not entirely benign; APOE*ε2 carriers exhibit increased risk of certain cerebrovascular diseases and neurological disorders. Here, we review evidence from both human and animal studies demonstrating the protective effect of APOE*ε2 against AD and propose a working model depicting potential underlying mechanisms. Finally, we discuss potential therapeutic strategies designed to leverage the protective effect of APOE2 to treat AD.

Associations of APOE e2 genotype with cerebrovascular pathology: a postmortem study of 1275 brains

OBJECTIVE

We assessed the association of apolipoprotein E (APOE) genotype with cerebrovascular disease (CVD) in a large neuropathological database maintained by the National Alzheimer's Coordinating Center (NACC). Such a comprehensive investigation of APOE and CVD pathology has not heretofore been conducted. We focused on APOE e2, an established neuroprotective genetic variant against Alzheimer's disease.

METHODS

To implement these objectives APOE associations in the NACC database of 1275 brains with 11 CVD pathologies, including old and recent infarcts, haemorrhages, cerebral amyloid angiopathy (CAA) and arteriosclerosis, were examined. These pathologies were uniformly and semiquantitatively measured across 39 Alzheimer's Disease Center sites. We used χ2 statistics and ordinal regression to assess the significance of associations and Bonferroni corrected for multiple comparisons.

RESULTS

Of the cases, 98 were e2/e3 or e2/e2 genotypes ('e2' carriers), 621 were e3 homozygotes ('e3' group), and 556 were e4/e3 (442) or e4/e4 (114) genotypes ('e4' group). Results indicated that the APOE e4 allele significantly increased risk for CAA. After stratification by CAA presence/absence, we found that in those cases in which CAA was present, APOE e2 significantly increased risk for gross haemorrhage. All other associations were negative.

CONCLUSIONS

In this, the largest study of APOE e2 effects on pathologically verified CVD, e2 was not protective against any CVD pathology compared with e3 homozygotes, including CAA. Regarding the latter pathology, e4 was associated with increases in its severity. Furthermore, and perhaps unexpectedly, e2 significantly increased risk of acute/subacute gross haemorrhage in the presence of CAA. Thus, there were limits to e2 neuroprotection against amyloidosis, despite its known and large protective effects against diffuse and neuritic amyloid plaques compared with e3/e3 and e4 carriers in this very collection.

Search for Reliable Circulating Biomarkers to Predict Carotid Plaque Vulnerability

Atherosclerosis is responsible for 20% of ischemic strokes, and the plaques from the internal carotid artery the most frequently involved. Lipoproteins play a key role in carotid atherosclerosis since lipid accumulation contributes to plaque progression and chronic inflammation, both factors leading to plaque vulnerability. Carotid revascularization to prevent future vascular events is reasonable in some patients with high-grade carotid stenosis. However, the degree of stenosis alone is not sufficient to decide upon the best clinical management in some situations. In this context, it is essential to further characterize plaque vulnerability, according to specific characteristics (lipid-rich core, fibrous cap thinning, intraplaque hemorrhage). Although these features can be partly detected by imaging techniques, identifying carotid plaque vulnerability is still challenging. Therefore, the study of circulating biomarkers could provide adjunctive criteria to predict the risk of atherothrombotic stroke. In this regard, several molecules have been found altered, but reliable biomarkers have not been clearly established yet. The current review discusses the concept of vulnerable carotid plaque, and collects existing information about putative circulating biomarkers, being particularly focused on lipid-related and inflammatory molecules.

Genetic Analysis of Patients With Sickle Cell Anemia and Stroke Before 4 Years of Age Suggest an Important Role for Apoliprotein E

BACKGROUND

Ischemic stroke is a devastating complication affecting children with sickle cell anemia. Genetic factors are likely to be important in determining the risk of stroke but are poorly defined.

METHODS

We have studied a cohort of 19 children who had an overt ischemic stroke before 4 years of age. We predicted genetic determinants of stroke would be more prominent in this group. We performed whole exome sequencing on this cohort and applied 2 hypotheses to our variant filtering. First, we looked for strong, potentially mono- or oligogenic variants for ischemic stroke, and second, we considered that more common polygenic variants will be enriched in our cohort. Candidate variants emerging from both strategies were validated in a cohort of 283 patients with sickle cell anemia and known pediatric cerebrovascular outcomes. We used principal component analysis in this cohort to control for relatedness and population substructure.

RESULTS

Our primary finding was that the Apoliprotein E genotypes ε2/ε4 and ε4/ ε4, defined by the interplay of rs7412 and rs429358, were associated with increased stroke risk, with an odds ratio of 4.35 ([95% CI, 1.85-10.0] P=0.0011) for ischemic stroke in the validation cohort. We also found that rs2297518 in NOS (NO synthase) 2 (odds ratio, 2.25 [95% CI, 1.21-4.19]; P=0.014) and rs2230123 in signal transducer and activator of transcription (odds ratio, 2.60 [95% CI, 1.30-5.20]; P=0.009) both had increased odds ratios for ischemic stroke, although these two variants were below the threshold for statistical significance after correction for multiple testing.

CONCLUSIONS

These data identify new loci for future functional investigations into cerebrovascular disease in sickle cell anemia. Based on African population reference allele frequencies, the Apoliprotein E genotypes would be present in about 10% of children with sickle cell anemia and represent a genetic risk factor that is potentially modifiable by both dietary and pharmaceutical manipulation of its dyslipidemic effects.