Plasma Apo Research Articles

Impact of APOE ε4 and ε2 on plasma neurofilament light chain and cognition in autosomal dominant Alzheimer’s disease

BackgroundApolipoprotein E (APOE) genotypes have been suggested to influence cognitive impairment and clinical onset in presenilin-1 (PSEN1) E280A carriers for autosomal dominant Alzheimer’s disease (ADAD). Less is known about their impact on the trajectory of biomarker changes. Neurofilament light chain (NfL), a marker of neurodegeneration, begins to accumulate in plasma about 20 years prior to the clinical onset of ADAD. In this study we investigated the impact of APOE ε4 and ε2 variants on age-related plasma NfL increases and cognition in PSEN1 E280A mutation carriers.MethodsWe analyzed cross-sectional data from PSEN1 E280A mutation carriers and non-carriers recruited from the Alzheimer’s Prevention Initiative Registry of ADAD. All participants over 18 years with available APOE genotype, plasma NfL, and neuropsychological evaluation were included in this study. APOE genotypes and plasma NfL concentrations were characterized for each participant. Cubic spline models using a Hamiltonian Markov chain Monte Carlo method were used to characterize the respective impact of at least one APOE ε4 or ε2 allele on age-related log-transformed plasma NfL increases. Linear regression models were estimated to explore the impact of APOE ε4 and ε2 variants and plasma NfL on a composite cognitive test score in the ADAD mutation carrier and non-carrier groups.ResultsAnalyses included 788 PSEN1 E280A mutation carriers (169 APOE ε4 + , 114 ε2 +) and 650 mutation non-carriers (165 APOE ε4 + , 80 ε2 +), aged 18–75 years. APOE ε4 allele carriers were distinguished from ε4 non-carriers by greater age-related NfL elevations in the ADAD mutation carrier group, beginning about three years after the mutation carriers’ estimated median age at mild cognitive impairment onset. APOE ε2 allele carriers had lower plasma NfL concentrations than ε2 non-carriers in both the ADAD mutation carrier and non-carrier groups, unrelated to age, and an attenuated relationship between higher NfL levels on cognitive decline in the ADAD mutation carrier group.ConclusionsAPOE ε4 accelerates age-related plasma NfL increases and APOE ε2 attenuates the relationship between higher plasma NfL levels and cognitive decline in ADAD. NfL may be a useful biomarker to assess clinical efficacy of APOE-modifying drugs with the potential to help in the treatment and prevention of ADAD.

Correlation of APOE polymorphism, expression, and plasma levels with cardiac comorbidities among lipodystrophy in HIV-infected patients

Lipodystrophy in HIV-infected patients (LDHIV) includes morphological and metabolic abnormalities, including lipid and glucose metabolism. ApoE plays a role in the transport and clearance of lipoprotein. In the general population, ApoE 112 (rs429358) and 158 (rs7412) polymorphisms were linked to severe dyslipidemia. Therefore, we investigated ApoE polymorphism using PCR-RFLP in 200 HIV patients (100 with HIV-associated lipodystrophy (HIVLD), 100 without HIVLD), as well as 100 healthy controls. We also assessed ApoE expression using qRT-PCR and measured its level using ELISA. The APOE 4/4, 3/4, and 2/4 genotypes have been associated with a decreased risk of HIV-1 infection. (P = 0.0001, OR = 0.18; P = 0.006, OR = 0.87; P = 0.006, OR = 0.09) when compared between HIV-positive individuals and healthy controls. Conversely, APOE allele 2 was linked to a higher risk of acquiring HIV-1 (P = 0.03, OR = 3.02). APOE allele 2 was linked to a higher likelihood of HIVLD severity when compared between patients with and without HIVLD (P = 0.05, OR = 2.82). When comparing patients with HIVLD to healthy controls, the APOE 4/4 and 2/4 genotypes as well as allele 4 were linked with the reduced risk of LDHIV (P = 0.0006, OR = 0.21; P = 0.01, OR = 0.18; P = 0.0002, OR = 0.40). When compared to patients without HIVLD from healthy controls, the ApoE 4/4 genotype, 2 and 4 alleles, were linked to a reduced risk of developing HIVLD (P = 0.0009, OR = 0.14; P = 0.0001, OR = 0.17; P = 0.00001, OR = 0.39). When comparing impaired to normal cholesterol levels in patients without HIVLD, the ApoE 3/4 genotype was linked with the increased risk of impaired cholesterol levels (P = 0.02, OR = 3.37). When comparing impaired and normal glucose levels in patients without HIVLD, the ApoE 4/4 genotype was associated to an elevated risk of impaired glucose levels (P = 0.03, OR = 8.27). In multivariate analysis, independent impaired cholesterol, LDL, and glucose levels were associated with a higher risk of lipodystrophy severity (P = 0.04, OR = 2.33; P = 0.001, OR = 4.05; P = 0.05, OR = 2.63). ApoE expression was up-regulated in LDHIV with a fold change value of 4.02 compared to those without HIVLD. ApoE protein level was found to be higher in patients of the HIVLD group (3.01 mg/dL) compared to those without HIVLD group (2.83 mg/dL). In conclusion, individuals with ApoE allele 2 were at higher risk for HIV-1 acquisition and severity of HIVLD, whereas those with ApoE allele 4 were at reduced HIVLD severity and development risk. It’s possible that ApoE’s increased level and its overexpression are related to the ApoE allele 2 in HIVLD patients. The development of LDHIV may be facilitated by the APOE 3/4 and 4/4 genotypes as well as abnormal glucose and cholesterol levels.

Lipid Metabolism Disorders as Diagnostic Biosignatures in Sepsis.

Critical illness causes disturbances in lipid metabolism. Here, we investigated the levels of apolipoprotein A-IV (apoA-IV), a regulator of triglyceride and cholesterol metabolism, in human sepsis. ApoA-IV (analyzed in 156 patients with systemic inflammatory response syndrome (SIRS)/sepsis) and cholesteryl ester (CE) (analyzed in 121 of these patients) were lower in patients compared to 43 healthy controls. In contrast, triglyceride (TG) levels were elevated in patients. ApoA-IV levels in plasma of the patients did not correlate with these lipids. Patients with SIRS, sepsis or septic shock had comparable apoA-IV, TG, CE and free cholesterol (FC) levels. Patients on dialysis had significantly lower CE levels, whereas apoA-IV levels did not change much. CE levels were elevated in patients with viral sepsis due to SARS-CoV-2 infection in comparison to SIRS/sepsis patients not infected by this virus. CE levels correlated negatively with procalcitonin, interleukin-6 and bilirubin, while TGs were positively associated with bilirubin and C-reactive protein. ApoA-IV, TG, CE and FC levels were not associated with bacterial infection or survival. In conclusion, this analysis suggests that CE levels decline in sepsis-related renal failure and also shows that plasma apoA-IV and CE levels are early biomarkers of sepsis.

The Influence of Aerobic Exercise on Nitric Oxide Signal Transduction and Related Cytokines in ApoE-/- Mice and the Underlying Mechanisms

Objective: To investigate the impact of aerobic exercise on nitric oxide (NO) signal transduction and related cytokines in ApoE-/- mice and its underlying mechanisms. Methods: ApoE-/- mice were divided into a control group and an aerobic exercise group. An 8-week aerobic exercise intervention using a treadmill training model was conducted to determine the expression levels of NO signal transduction-related cytokines. Results: Aerobic exercise significantly increased the expression of NO and related cytokines in the plasma of ApoE-/- mice and reduced the level of inflammatory factors. Conclusion: Aerobic exercise can enhance NO signal transduction, reduce inflammatory responses, and improve the cardiovascular function of ApoE-/- mice.

Divergent Roles of APOAI and APOM in the Identification of Alcohol Use Disorder and Their Association With Inflammation and Cognitive Decline: A Pilot Study.

Alcohol use disorder (AUD) courses with inflammation and cognitive decline. Apolipoproteins have emerged as novel target compounds related to inflammatory processes and cognition. A cross-sectional study was performed on abstinent AUD patients with at least 1 month of abstinence (n = 33; 72.7% men) and healthy controls (n = 34; 47.1% men). A battery of plasma apolipoproteins (APOAI, APOAII, APOB, APOCII, APOE, APOJ, and APOM), plasma inflammatory markers (LPS, LBP), and their influence on cognition and presence of the disorder were investigated. Higher levels of plasma APOAI, APOB, APOE, and APOJ, as well as the proinflammatory LPS, were observed in the AUD group, irrespective of sex, whereas APOM levels were lower vs controls. Hierarchical logistic regression analyses, adjusting for covariates (age, sex, education), associated APOM with the absence of cognitive impairment in AUD and identified APOAI and APOM as strong predictors of the presence or absence of the disorder, respectively. APOAI and APOM did not correlate with alcohol abuse variables or liver status markers, but they showed an opposite profile in their associations with LPS (positive for APOAI; negative for APOM) and cognition (negative for APOAI; positive for APOM) in the entire sample. The HDL constituents APOAI and APOM were differentially regulated in the plasma of AUD patients compared with controls, playing divergent roles in the disorder identification and associations with inflammation and cognitive decline.

Differential distribution of plasma apoA-I and apoB levels and clinical significance of apoB/apoA-I ratio in ischemic stroke subtypes.

Ischemic stroke (IS) is classified into clinical subtypes and likely influenced by various lipid components. Nevertheless, the roles of apolipoprotein A-I (apoA-I), apolipoprotein B (apoB), and apoB/apoA-I ratio in different IS subtypes remain underexplored. This study aimed to investigate the differential distribution of plasma apoA-I and apoB levels among IS subtypes and to evaluate the predictive value of the apoB/apoA-I ratio in assessing IS subtypes and disease severity. In this study, 406 IS patients were categorized into three IS-subtypes based on clinical manifestations and imaging assessment, including intracranial atherosclerosis-related IS patients (ICAS, n = 193), extracranial atherosclerosis-related IS patients (ECAS, n = 111), and small artery occlusion-related IS patients (SAO, n = 102). Plasma apoA-I and apoB levels were measured upon hospital admission. Random forest (RF) models were performed to assess predictive values of these apolipoproteins apoB, apoA-I and their ratio in assessing IS subtype stratification and disease severity. Serum apoA-I levels were significantly lower in ICAS compared to ECAS and SAO patients (p < 0.0001), while apoB levels were higher in ICAS patients (p < 0.0001). The apoB/apoA-I ratio was significantly higher in ICAS compared to ECAS and SAO patients (p < 0.0001). Correlation analyses found a significant correlation between the apoB/apoA-I ratio and conventional lipid components. Additionally, RF models and plots of variable importance and distribution of minimal depth revealed that the apoB/apoA-I ratio played the most influential predictor in predicting IS subtypes and stenosis severity. Our study shows the differential distribution of apoA-I and apoB IS subtypes and reveals the significance of the apoB/apoA-I ratio in assessing IS subtypes and arterial stenosis severity. Further studies are warranted to validate these findings and enhance their clinical applicability.

The AlzMatch Pilot Study - Feasibility of Remote Blood Collection of Plasma Biomarkers for Preclinical Alzheimer’s Disease Trials

BackgroundAdvances in plasma biomarkers to detect Alzheimer’s disease (AD) biology allows researchers to improve the efficiency of participant recruitment into preclinical trials. Recently, protein levels of plasma amyloid-beta and tau proteins have been shown to be predictive of elevated amyloid in brain. Online registries, such as the Alzheimer’s Prevention Trials (APT) Webstudy, include and follow participants using remote assessments to facilitate efficient screening and enrollment of large numbers of individuals who may be at higher risk for AD.ObjectivesThe AlzMatch Pilot Study investigated the feasibility of recruiting individuals from an online registry for blood sample collection at community-based phlebotomy centers and plasma biomarker quantification to assess an individual’s eligibility for AD preclinical trials.DesignPilot feasibility study with co-primary outcomes.SettingThis pilot feasibility study included participants from the APT Webstudy, the remote assessment arm of the Trial-ready cohort for Preclinical and Prodromal AD (TRC-PAD) Platform. Novel design included collection of electronic consent, use of community laboratories for plasma collection, mass spectrometry-based biomarker assay, and telephone communication of plasma biomarker screening eligibility.ParticipantsParticipants invited to the AlzMatch pilot feasibility study were active in the APT Webstudy, 50 years of age or older, resided within 50 miles of both a Quest Diagnostics Patient Services Center (a national diagnostic laboratory with convenient locations for sample collection and processing) and one of six TRC-PAD vanguard clinical trial sites, had no self-reported dementia diagnosis, were able to communicate in English and engaged with the APT Webstudy within the prior 6 months.MeasurementsPrimary feasibility outcomes were completion of electronic consent (e-consent) for invited participants and collection of usable blood samples. Additional feasibility outcomes included invitation response rate, plasma biomarker eligibility status (based on amyloid beta-42/40 [Aβ42/40] concentration ratio), ApoE proteotype, and trial inclusion criterion), and completion of telephone contact to learn eligibility to screen for a study.Results300 APT Webstudy participants were invited to consent to the AlzMatch study. The AlzMatch e-consent rate was 39% (n=117) (95% CI of 33.5%–44.5%) overall, which was higher than the expected rate of 25%. Similar consent rates were observed across participants based on self-defined sex (41% Female (n=75), 37% Male (n=42)) and race and ethnicity (37% from underrepresented groups (URG) (n=36), 40% not from URG (n=79)). Among those that consented (n=117), plasma was successfully collected from 74% (n=87) (95% CI of 66%–82%), with similar rates across sex (76% Female (n=57), 71% Male (n=30)) and race and ethnicity (75% URG (n=27) and 75% not from URG (n=59)). 60% (n=51) of participants with plasma biomarker results were eligible to screen for future preclinical AD trials.ConclusionElectronic consent of participants through an online registry, blood sample collection at community-based centers, plasma biomarker quantification and reporting, and biomarker assessments for study eligibility were all feasible with similar engagement rates across demographic groups. Although this pilot was a small and selective sample, participants engaged and consented at higher than expected rates. We conclude that collecting blood at community laboratories for biomarker analyses may improve accessibility beyond research, and may facilitate broader access for clinical use of AD plasma biomarkers. Based on our results, an expanded version of the AlzMatch study is underway, which involves expanding invitations to additional APT Webstudy participants and clinical trial sites.

APOE Genotype, ApoE Plasma Levels, Lipid Metabolism, and Cognition in Monozygotic Twins with, at Risk of, and without Affective Disorders.

Background: Lipids influence brain function and mental health. Understanding the role of apolipoproteins in affective disorders could provide valuable insights and potentially pave the way for novel therapeutic approaches. Methods: We examined the apolipoprotein E genotype and ApoE-levels, lipid profiles, and the correlation with cognition in 204 monozygotic (MZ) twins with unipolar or bipolar disorder in remission or partial remission (affected, AT), their unaffected co-twins (high-risk, HR), and twins with no personal or family history of affective disorder (low-risk, LR). Results: The APOE genotype was not associated with affective disorders. No significant group differences in ApoE levels were found between the three risk groups. Post hoc analysis group-wise comparisons showed higher ApoE levels in the AT than HR twins and in the concordant AT twin pairs relative to the discordant twin pairs. Within the discordant twin pairs, higher ApoE levels were observed in the affected twins (AT = 39.4 mg/L vs. HR = 36.8 mg/L, p = 0.037). Limitations: The present study could benefit from a larger sample size. We did not assess dietary habits. Conclusions: The results did not support our main hypothesis. However, exploratory post hoc analysis suggests a role for plasma ApoE and triglycerides in affective disorders. Future research is needed.

Plasma oxysterols are associated with serum lipids and dementia risk in older women.

Apolipoprotein E4 (APOE4) carriers' tendency toward hypercholesterolemia may contribute to Alzheimer's disease (AD) risk through oxysterols, which traverse the blood-brain barrier. Relationships between baseline plasma oxysterols, APOE status, serum lipids, and cognitive impairment risk were examined in 328 postmenopausal women from the Women's Health Initiative Memory Study. Women were followed for 25 years or until incident dementia or cognitive impairment. Levels of 24(S)-hydroxycholesterol (24-OHC), 27-hydroxycholesterol (27-OHC), and 24-OHC/27-OHC ratio did not differ by APOE status (p's>0.05). Higher 24-OHC and 27-OHC were associated with higher total, low density lipoprotein (LDL), non-high density lipoprotein (HDL), remnant, LDL/HDL, and total/HDL cholesterol and triglycerides (p's<0.05). Higher 24-OHC/27-OHC was associated with greater dementia risk (hazard ratio=1.51, 95% confidence interval:1.02-2.22), which interaction analyses revealed as significant for APOE3 and APOE4+, but not APOE2+ carriers. Less favorable lipid profiles were associated with higher oxysterol levels. A higher ratio of 24-OHC/27-OHC may contribute to dementia risk in APOE3 and APOE4+ carriers.

Sensitivity of the African neuropsychology battery memory subtests and learning slopes in discriminating APOE 4 and amyloid pathology in adult individuals in the Democratic Republic of Congo.

The current study examined the sensitivity of two memory subtests and their corresponding learning slope metrics derived from the African Neuropsychology Battery (ANB) to detect amyloid pathology and APOEε4 status in adults from Kinshasa, the Democratic Republic of the Congo. 85 participants were classified for the presence of β-amyloid pathology and based on allelic presence of APOEε4 using Simoa. All participants were screened using CSID and AQ, underwent verbal and visuospatial memory testing from ANB, and provided blood samples for plasma Aβ42, Aβ40, and APOE proteotype. Pearson correlation, linear and logistic regression were conducted to compare amyloid pathology and APOEε4 status with derived learning scores, including initial learning, raw learning score, learning over trials, and learning ratio. Our sample included 35 amyloid positive and 44 amyloid negative individuals as well as 42 without and 39 with APOEε4. All ROC AUC ranges for the prediction of amyloid pathology based on learning scores were low, ranging between 0.56-0.70 (95% CI ranging from 0.44-0.82). The sensitivity of all the scores ranged between 54.3-88.6, with some learning metrics demonstrating good sensitivity. Regarding APOEε4 prediction, all AUC values ranged between 0.60-0.69, with all sensitivity measures ranging between 53.8-89.7. There were minimal differences in the AUC values across learning slope metrics, largely due to the lack of ceiling effects in this sample. This study demonstrates that some ANB memory subtests and learning slope metrics can discriminate those that are normal from those with amyloid pathology and those with and without APOEε4, consistent with findings reported in Western populations.

Comparative analysis of multimodal biomarkers for amyloid-beta positivity detection in Alzheimer's disease cohorts.

Efforts to develop cost-effective approaches for detecting amyloid pathology in Alzheimer's disease (AD) have gained significant momentum with a focus on biomarker classification. Recent research has explored non-invasive and readily accessible biomarkers, including magnetic resonance imaging (MRI) biomarkers and some AD risk factors. In this comprehensive study, we leveraged a diverse dataset, encompassing participants with varying cognitive statuses from multiple sources, including cohorts from the Alzheimer's Disease Neuroimaging Initiative (ADNI) and our in-house Dementia Disease Initiation (DDI) cohort. As brain amyloid plaques have been proposed as sufficient for AD diagnosis, our primary aim was to assess the effectiveness of multimodal biomarkers in identifying amyloid plaques, using deep machine learning methodologies. Our findings underscore the robustness of the utilized methods in detecting amyloid beta positivity across multiple cohorts. Additionally, we investigated the potential of demographic data to enhance MRI-based amyloid detection. Notably, the inclusion of demographic risk factors significantly improved our models' ability to detect amyloid-beta positivity, particularly in early-stage cases, exemplified by an average area under the ROC curve of 0.836 in the unimpaired DDI cohort. These promising, non-invasive, and cost-effective predictors of MRI biomarkers and demographic variables hold the potential for further refinement through considerations like APOE genotype and plasma markers.

Bacterial lipopolysaccharide forms aggregates with apolipoproteins in male and female rat brains after ethanol binges

Alcohol binge drinking allows the translocation of bacterial lipopolysaccharide (LPS) from the gut to the blood, which activates the peripheral immune system with consequences in neuroinflammation. A possible access/direct signaling of LPS to/in the brain has not yet been described under alcohol abuse conditions. Apolipoproteins are compounds altered by alcohol with high affinity to LPS which may be involved in its transport to the brain or in its elimination. Here, we explored the expression of small components of LPS, in its free form or bound to apolipoproteins, in the brain of female and male rats exposed to alcohol binges. Animals received ethanol oral gavages (3 g/kg every 8 h) for 4 days. LPS or its components (Lipid A and core), LPS-binding protein, corticosterone, lipoproteins (HDL, LDL), apolipoproteins (ApoAI, ApoB, and ApoE), and their receptors were measured in plasma and/or in nonperfused prefrontal cortex (PFC) and cerebellum. Brain LipidA-apolipoprotein aggregates were determined by Western blotting and confirmed by co-immunoprecipitation. In animals exposed to alcohol binges: 1) plasma LPS-binding protein was elevated in both sexes; 2) females showed elevations in plasma ApoAI and corticosterone levels; 3) Lipid A formed aggregates with ApoAI in the female PFC and with ApoB in males, the latter showing Toll-like receptor 4 upregulation in PFC but not females. These results suggest that small bacterial components are present within the brain, forming aggregates with different apolipoproteins, depending on the sex, after alcohol binge intoxications. Results may have implications for the crosstalk between alcohol, LPS, and neuroinflammation.

Plasma Apo-E mediated corticospinal tract abnormalities and suicidality in patients with major depressive disorder.

This study aims to explore the link between Apo-E, brain white matter, and suicide in patients with major depressive disorder (MDD) to investigate the potential neuroimmune mechanisms of Apo-E that may lead to suicide. Thirty-nine patients with MDD (22 patients with suicidality) and 57 age, gender, and education-matched healthy controls participated in this study, provided plasma Apo-E samples, and underwent diffusion tensor imaging scans. Plasma Apo-E levels and white matter microstructure were analyzed among the MDD with suicidality, MDD without suicidality, and HC groups using analysis of variance with post hoc Bonferroni correction and tract-based spatial statistics (TBSS) with threshold-free cluster enhancement correction. Mediation analysis investigated the relationship between Apo-E, brain white matter, and suicidality in MDD. The MDD with suicidality subgroup had higher depressive and suicide scores, longer disease course, and lower plasma Apo-E levels than MDD without suicidality. TBSS revealed that the MDD non-suicide subgroup showed significantly increased mean diffusivity in the left corticospinal tract and body of the left corpus callosum, as well as increased axial diffusivity in the left anterior corona radiata and the right posterior thalamic radiation compared to the suicidal MDD group. The main finding was that the increased MD of the left corticospinal tract contributed to the elevated suicide score, with Apo-E mediating the effect. Preliminary result that Apo-E's mediating role between the left corticospinal tract and the suicide factor suggests the neuroimmune mechanism of suicide in MDD. The study was registered on ClinicalTrials.gov (NCT03790085).

Elevated plasma apolipoprotein E levels in people living with HIV: Associations with biomarkers and HIV-specific risk factors

Background and aimsApolipoprotein E (apoE) plays a crucial role in cholesterol metabolism, and high levels of apoE in plasma are associated with cardiovascular disease and all-cause mortality. We aimed to assess if HIV is independently associated with high plasma apoE and to determine HIV-related risk factors for high plasma apoE. MethodsWe included 661 people with HIV (PWH) from the Copenhagen Comorbidity in HIV (COCOMO) study with available measurement of plasma apoE. COCOMO participants were frequency matched 1:1 on age and sex with controls from the Copenhagen General Population Study. High plasma apoE was defined as levels above the 90th percentile (66.2 mg/L). The association between HIV and high plasma apoE was assessed using logistic regression models. Among PWH, both linear and logistic regression models were used to determine HIV-specific risk factors for high plasma apoE. ResultsMean age was 52 years and 89 % were male. Median plasma apoE was 49.0 mg/L in PWH and 43.3 mg/L in controls, p < 0.001. HIV was associated with higher plasma apoE after adjusting for potential confounders, including triglycerides (odds ratio 2.14 [95 % CI: 1.39–3.29], p < 0.001). In PWH, higher plasma apoE was associated with a previous AIDS-defining condition in linear models before adjustment for triglycerides and integrase strand transfer inhibitor use in fully adjusted linear models. ConclusionsPWH had higher plasma apoE than controls even after adjusting for triglycerides. Further studies are needed to elucidate the clinical impact of high plasma apoE in PWH.

－75 G/A Polymorphism of Apolipoprotein A1 Gene Promoter Region in Normal Pregnant Women and Patients With Gestational Diabetes Mellitus

To investigate the －75 G/A single-nucleotide polymorphism in the promoter region of apolipoprotein A1 gene (apoA1) and its association with gestational diabetes mellitus (GDM) in pregnant women and to provide references for the exploration in the molecular genetic basis of GDM. A total of 626 GDM patients and 1022 normal pregnant women, ie, the controls, were included in the study. The genotyping of apoA1 －75 G/A polymorphism was performed by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. Total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and glucose (Glu) were measured by enzymatic methods. Plasma insulin (INS) was measured by chemiluminescence immunoassay. The protein levels of apoA1 and apoB were measured by the turbidimetric immunoassay. Allele frequencies of G and A were 0.718 and 0.282 in the GDM group and 0.713 and 0.287 in the control group, respectively. Distribution of the genotype frequencies was found to be in Hardy-Weinberg equilibrium in both the GDM and control groups. There was no significant difference in the frequencies of alleles G and A and the genotypes of apoA1 －75 G/A polymorphism between the GDM and the control group (P>0.05). In the GDM group, the carriers with the genotype AA were associated with significantly higher levels of TC, HDL-C, and apoA1 than those with genotypes GG and GA did (all P<0.05). After the GDM patients were divided into obese and non-obese subgroups, the genotype-related apoA1 variation was observed only in obese patients, while the genotype-related TC and HDL-C variations were evident in non-obese patients (P<0.05). In the control group, carriers of genotypes AA and GA had higher systolic blood pressure (SBP) and HDL-C than the carriers of genotype GG did (all P<0.05). Carriers of genotypes AA had significantly lower Glu levels than carriers of genotypes GG and GA did (P<0.05). The control subjects were further divided into subgroups according to their body mass index (BMI). Analysis of the subgroups showed that AA carriers were associated with higher SBP levels in the obese control women only, while lower Glu levels were evident in both obese and non-obese control women. These results suggest that －75 G/A polymorphism in the apoA1 gene is not associated with GDM. However, the genetic variation is closed associated with the plasma apoA1, HDL-C, and TC levels in GDM patients and plasma HDL-C, Glu, and SBP levels in the control subjects. The apoA1 variant-associated lipids and SBP variation is BMI dependent in both groups.

Association of plasma biomarkers with cognitive function in persons with dementia and cognitively healthy in the Democratic Republic of Congo

AbstractBackgroundCross‐sectional and longitudinal measurements of plasma biomarkers of Alzheimer’s disease (AD) in Western countries are being applied in clinical practice, whereas their associations with culturally validated cognitive tests in other settings remain unknown. We aim to examine cross‐sectional association of plasma protein biomarker concentrations and APOE proteotype with cognitive function and explore the discriminative role of these AD biomarkers in such an association.MethodThis is a cross‐sectional retrospective study completed from 2018 to 2022 in the Democratic Republic of Congo (DRC). Subjects were recruited from clinics, hospitals, churches, and across DRC. The study started in January 2018 until December 2022. Data were analyzed from May 2022 to December 2022. The DRC Memory clinic team recruited 1430 individuals 65 years and over. Based on Community Screening Instruments for Dementia (CSID), and Alzheimer’s Questionnaire (AQ), and DSM‐5 diagnostic criteria, participants included 44 individuals classified as major neurocognitive disorder (dementia) and 41 as healthy controls (HC). Subjects underwent cognitive assessment with a validated, culturally‐tailored cognitive battery. AD plasma biomarkers (Aβ42, Aβ40, Aβ42/40, p‐tau 181), APS (derived from Aβ42/40, APOE status, and age), and APOE proteotype were utilized to assess for genetic risk.ResultIndividuals with dementia had significantly lower Aβ42/40 levels, higher APS, and higher APOE ε4 prevalence compared to HC. Linear regressions showed significantly associations between Aβ42/40 and APS with ANT, ALMT, and AVMT scores, while APOE ε4 presence was associated with ANT, ALMT, AVMT, and APT scores. APS showed the highest AUC value (AUC = 0.78, 95% CI: 0.68‐0.88) followed by Aβ42/40 (AUC = 0.75, 95% CI: 0.66‐0.86) and APOE ε4 (AUC = 0.69 (CI 0.57‐0.81) in discriminating dementia from HC.ConclusionSelect AD biomarkers were associated with cognition and differentiated dementia from HC, consistent with extant research. These findings may have implications for the assessment of AD biomarkers in DRC.

Genome-wide analysis identifies novel loci influencing plasma apolipoprotein E concentration and Alzheimer’s disease risk

The APOE 2/3/4 polymorphism is the greatest genetic risk factor for Alzheimer’s disease (AD). This polymorphism is also associated with variation in plasma ApoE level; while APOE*4 lowers, APOE*2 increases ApoE level. Lower plasma ApoE level has also been suggested to be a risk factor for incident dementia. To our knowledge, no large genome-wide association study (GWAS) has been reported on plasma ApoE level. This study aimed to identify new genetic variants affecting plasma ApoE level as well as to test if baseline ApoE level is associated with cognitive function and incident dementia in a longitudinally followed cohort of the Ginkgo Evaluation of Memory (GEM) study. Baseline plasma ApoE concentration was measured in 3031 participants (95.4% European Americans (EAs)). GWAS analysis was performed on 2580 self-identified EAs where both genotype and plasma ApoE data were available. Lower ApoE concentration was associated with worse cognitive function, but not with incident dementia. As expected, the risk for AD increased from E2/2 through to E4/4 genotypes (P for trend = 4.8E-75). In addition to confirming the expected and opposite associations of APOE*2 (P = 4.73E-79) and APOE*4 (P = 8.73E-12) with ApoE level, GWAS analysis revealed nine additional independent signals in the APOE region, and together they explained about 22% of the variance in plasma ApoE level. We also identified seven new loci on chromosomes 1, 4, 5, 7, 11, 12 and 20 (P range = 5.49E-08 to 5.36E-10) that explained about 9% of the variance in ApoE level. Plasma ApoE level-associated independent variants, especially in the APOE region, were also associated with AD risk and amyloid deposition in the brain, indicating that genetically determined ApoE level variation may be a risk factor for developing AD. These results improve our understanding of the genetic determinants of plasma ApoE level and their potential value in affecting AD risk.

Multivessel Coronary Artery Disease Complicated by Diabetes Mellitus Has a Relatively Small Effect on Endothelial and Lipoprotein Lipases Expression in the Human Atrial Myocardium and Coronary Perivascular Adipose Tissue.

Endothelial (EL) and lipoprotein (LPL) lipases are enzymes involved in lipoproteins metabolism and formation of atherosclerosis, a pathological feature of coronary artery disease (CAD). This paper examines the role of the lipases in the right atrial appendage (RAA) and coronary perivascular adipose tissue (PVAT) of patients with CAD alone or with accompanying diabetes. Additionally, correlation analysis for plasma concentration of the lipases, apolipoproteins (ApoA-ApoJ) and blood lipids (Chol, HDL-C, LDL-C, TAG) was performed. We observed that CAD had little effect on the lipases gene/protein levels in the RAA, while their transcript content was elevated in the PVAT of diabetic CAD patients. Interestingly, the RAA was characterized by higher expression of EL/LPL (EL: +1-fold for mRNA, +5-fold for protein; LPL: +2.8-fold for mRNA, +12-fold for protein) compared to PVAT. Furthermore, ApoA1 plasma concentration was decreased, whereas ApoC1 and ApoH were increased in the patients with CAD and/or diabetes. The concentrations of ApoC3 and ApoD were strongly positively correlated with TAG content in the blood, and the same was true for ApoB with respect to LDL-C and total cholesterol. Although plasma concentrations of EL/LPL were elevated in the patients with diabetes, CAD alone had little effect on blood, myocardial and perivascular fat expression of the lipases.

Plasminogen Receptors Promote Lipoprotein(a) Uptake by Enhancing Surface Binding and Facilitating Macropinocytosis.

High levels of Lp(a) (lipoprotein(a)) are associated with multiple forms of cardiovascular disease. Lp(a) consists of an apoB100-containing particle attached to the plasminogen homologue apo(a). The pathways for Lp(a) clearance are not well understood. We previously discovered that the plasminogen receptor PlgRKT (plasminogen receptor with a C-terminal lysine) promoted Lp(a) uptake in liver cells. Here, we aimed to further define the role of PlgRKT and to investigate the role of 2 other plasminogen receptors, annexin A2 and S100A10 (S100 calcium-binding protein A10) in the endocytosis of Lp(a). Human hepatocellular carcinoma (HepG2) cells and haploid human fibroblast-like (HAP1) cells were used for overexpression and knockout of plasminogen receptors. The uptake of Lp(a), LDL (low-density lipoprotein), apo(a), and endocytic cargos was visualized and quantified by confocal microscopy and Western blotting. The uptake of both Lp(a) and apo(a), but not LDL, was significantly increased in HepG2 and HAP1 cells overexpressing PlgRKT, annexin A2, or S100A10. Conversely, Lp(a) and apo(a), but not LDL, uptake was significantly reduced in HAP1 cells in which PlgRKT and S100A10 were knocked out. Surface binding studies in HepG2 cells showed that overexpression of PlgRKT, but not annexin A2 or S100A10, increased Lp(a) and apo(a) plasma membrane binding. Annexin A2 and S100A10, on the other hand, appeared to regulate macropinocytosis with both proteins significantly increasing the uptake of the macropinocytosis marker dextran when overexpressed in HepG2 and HAP1 cells and knockout of S100A10 significantly reducing dextran uptake. Bringing these observations together, we tested the effect of a PI3K (phosphoinositide-3-kinase) inhibitor, known to inhibit macropinocytosis, on Lp(a) uptake. Results showed a concentration-dependent reduction confirming that Lp(a) uptake was indeed mediated by macropinocytosis. These findings uncover a novel pathway for Lp(a) endocytosis involving multiple plasminogen receptors that enhance surface binding and stimulate macropinocytosis of Lp(a). Although the findings were produced in cell culture models that have limitations, they could have clinical relevance since drugs that inhibit macropinocytosis are in clinical use, that is, the PI3K inhibitors for cancer therapy and some antidepressant compounds.

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

Background and aimsThe 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. MethodsWe 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. ResultsRare 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. ConclusionsAPOE 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.