Plasma Apo Research Articles

Abstract 118: Cholesteryl Ester Transfer Protein Overrides The Protective Effect Of APOA1 On Arterial APOB Lipoprotein Trapping And Atherosclerosis Progression In A Mouse Model Of Type 1 Diabetes

Despite the benefits of LDL-cholesterol-reducing medications, patients with type 1 diabetes (T1D) continue to have an increased risk of incident CVD. Preclinical and clinical observations indicate that triglyceride-rich lipoproteins (TRLs) and their remnants may contribute significantly to CVD risk in T1D. Recently, we have shown that diabetes increases levels of atherogenic TRL remnants and that improvement of remnant clearance halts atherosclerosis in a mouse model of T1D. Cholesteryl ester transfer protein (CETP), which is normally absent in mice, links metabolism of TRLs to that of HDL by mediating the transfer of cholesteryl ester from HDL to VLDL and other APOB-containing lipoproteins in exchange for triglycerides. We hypothesized that CETP impairs the atheroprotective effects of APOA1 by altering TRL and HDL metabolism in diabetes. To test this hypothesis, we developed a virally-induced T1D mouse model expressing the human APOA1 transgene ( APOA1 Tg , Ldlr –/– ). Cohorts of these mice were injected with a liver-targeted adeno-associated virus to express human CETP, and the effects on lipoproteins, plasma apolipoproteins, HDL particle concentrations (HDL-P), and atherosclerosis in the presence and absence of diabetes were determined. This mouse model exhibits an HDL profile similar to humans, with small, medium and large HDL-P, whereas wildtype ( Ldlr -/- ) littermates have only one sized HDL-P. Expression of the APOA1 transgene significantly suppressed diabetes-accelerated necrotic core expansion and accumulation of APOB and APOE in the aortic sinus (compared to wildtype Ldlr -/- mice), while CETP impaired the protective effect of APOA1 on these parameters in diabetic APOA1 Tg , Ldlr –/– mice (n= 22-30, p < 0.05). Further characterization of plasma lipoproteins and apolipoproteins by targeted mass spectrometry, FPLC and differential ion mobility analysis indicated that CETP leads to smaller TRL remnant particles, increases triglyceride content in HDL, lower levels of plasma APOA1 and reduction in large HDL-P under diabetic conditions (n= 8-10, p < 0.05). Our results are consistent with the proposal that inhibition of CETP might be cardioprotective in the setting of T1D and highlight the close links between TRL and HDL metabolism in diabetes.

Brain integrity is altered by hepatic APOE ε4 in humanized-liver mice

Liver-generated plasma apolipoprotein E (apoE) does not enter the brain but nonetheless correlates with Alzheimer’s disease (AD) risk and AD biomarker levels. Carriers of APOEε4, the strongest genetic AD risk factor, exhibit lower plasma apoE and altered brain integrity already at mid-life versus non-APOEε4 carriers. Whether altered plasma liver-derived apoE or specifically an APOEε4 liver phenotype promotes neurodegeneration is unknown. Here we investigated the brains of Fah−/−, Rag2−/−, Il2rg−/− mice on the Non-Obese Diabetic (NOD) background (FRGN) with humanized-livers of an AD risk-associated APOE ε4/ε4 versus an APOE ε2/ε3 genotype. Reduced endogenous mouse apoE levels in the brains of APOE ε4/ε4 liver mice were accompanied by various changes in markers of synaptic integrity, neuroinflammation and insulin signaling. Plasma apoE4 levels were associated with unfavorable changes in several of the assessed markers. These results propose a previously unexplored role of the liver in the APOEε4-associated risk of neurodegenerative disease.

Combining plasma phospho-tau and accessible measures to evaluate progression to Alzheimer\u2019s dementia in mild cognitive impairment patients

BackgroundUp to now, there are no clinically available minimally invasive biomarkers to accurately identify mild cognitive impairment (MCI) patients who are at greater risk to progress to Alzheimer’s disease (AD) dementia. The recent advent of blood-based markers opens the door for more accessible biomarkers. We aimed to identify which combinations of AD related plasma biomarkers and other easily accessible assessments best predict progression to AD dementia in patients with mild cognitive impairment (MCI).MethodsWe included patients with amnestic MCI (n = 110) followed prospectively over 3 years to assess clinical status. Baseline plasma biomarkers (amyloid-β 42/40, phosphorylated tau217 [p-tau217], neurofilament light and glial fibrillary acidic protein), hippocampal volume, APOE genotype, and cognitive tests were available. Logistic regressions with conversion to amyloid-positive AD dementia within 3 years as outcome was used to evaluate the performance of different biomarkers measured at baseline, used alone or in combination. The first analyses included only the plasma biomarkers to determine the ones most related to AD dementia conversion. Second, hippocampal volume, APOE genotype and a brief cognitive composite score (mPACC) were combined with the best plasma biomarker.ResultsOf all plasma biomarker combinations, p-tau217 alone had the best performance for discriminating progression to AD dementia vs all other combinations (AUC 0.84, 95% CI 0.75–0.93). Next, combining p-tau217 with hippocampal volume, cognition, and APOE genotype provided the best discrimination between MCI progressors vs. non-progressors (AUC 0.89, 0.82–0.95). Across the few best models combining different markers, p-tau217 and cognition were consistently the main contributors. The most parsimonious model including p-tau217 and cognition had a similar model fit, but a slightly lower AUC (0.87, 0.79–0.95, p = 0.07).ConclusionWe identified that combining plasma p-tau217 and a brief cognitive composite score was strongly related to greater risk of progression to AD dementia in MCI patients, suggesting that these measures could be key components of future prognostic algorithms for early AD.Trial registrationNCT01028053, registered December 9, 2009.

PCSK9 inhibition with alirocumab decreases plasma lipoprotein(a) concentration by a dual mechanism of action in statin‐treated patients with very high apolipoprotein(a) concentration

Inhibition of proprotein convertase subtilisin/kexin type 9 with alirocumab decreases plasma lipoprotein(a) [Lp(a)] levels. The kinetic mechanism for lowering Lp(a) by alirocumab may differ according to pre-treatment apolipoprotein(a) [apo(a)] levels. The effect of 12-week alirocumab (150 mg subcutaneously fortnightly) on the kinetics of apo(a) was compared in statin-treated patients with high (n = 10) and very high Lp(a) concentrations (n = 11). In patients with high apo(a) concentrations, alirocumab lowered plasma apo(a) pool size (-17%, p < 0.01) chiefly by increasing the fractional catabolic rate (FCR) of apo(a) (+27%, p < 0.001). By contrast in patients with very high apo(a) concentrations, alirocumab significantly lowered plasma apo(a) pool size (-32%, p < 0.001) by both increasing apo(a) FCR (+30%, p < 0.001) and lowering production rate (-11%, p < 0.05). In statin-treated patients with very high apo(a) concentrations, alirocumab lowers plasma Lp(a) concentration by a dual mode of action that increases the clearance and decreases the production of Lp(a) particles.

Evaluation of S100A12 and Apo-A1 plasma level potency in untreated new relapsing\u2013remitting multiple sclerosis patients and their family members

Multiple sclerosis is an inflammatory disease of the spinal cord and brain. Receptor for advanced glycation end products and Apolipoprotein A1 (Apo-AI) have been recommended to have a pathogenic role in the neuroinflammatory disorder as multiple sclerosis. The purpose of this research was to measure the plasma levels of S100A12 and Apo-A1 in the first-degree family of relapsing–remitting multiple sclerosis (RRMS) patients. Plasma levels of S100A12 & Apo-A1 were evaluated via enzyme-linked immunosorbent assay in the thirty-five new cases of untreated patients with deterministic RRMS according to the McDonald criteria, twenty-four healthy controls, and twenty-six first-degree members of untreated RRMS patients (called them as high-risk group). The main findings of this study were as follows: the plasma level of S100A12 was significantly lower in the new cases of untreated RRMS (P ≤ 0.05; 0.045) and high-risk (P ≤ 0.05; 0.001) groups. Although the plasma protein level of Apo-A1 was reduced significantly in the high-risk group (P < 0.05, P = 0.003) as compared to the healthy control group, there was no significant difference in the untreated RRMS patients (P = 0.379). The plasma level of vitamin D3 in both RRMS patients and high-risk groups displayed significance reduction, although, there was no significant association between vitamin D and S100A12 & Apo-A1 levels. Given the role of S100A12 and Apo-A1 in the inflammatory process performed in the first-degree family members of the RRMS patients, which revealed a significant decrease in this group, we concluded that they can be considered as one of the contributing factors in the pathogenesis of MS, though more research is needed before assuming them as predictive biomarkers.

Plasma apolipoprotein concentrations and incident diabetes in subjects with prediabetes

BackgroundThe identification of circulating biomarkers associated with the risk of type 2 diabetes (T2D) is useful for improving the current prevention strategies in the most at-risk patients. Here, we aimed to investigate the association of plasma apolipoprotein concentrations in prediabetes subjects with the incidence of new-onset T2D during follow-up.MethodsIn the IT-DIAB prospective study, 307 participants with impaired fasting glucose levels (fasting plasma glucose [FPG]: 110–125 mg/dL) were followed yearly for 5 years. The onset of T2D was defined as a first FPG value ≥ 126 mg/dL during follow-up. Apolipoprotein (apo)A-I, A-II, A-IV, B100, C-I, C-II, C-III, C-IV, D, E, F, H, J, L1, M, and (a) plasma concentrations were determined by mass spectrometry. Correlations between apolipoproteins and metabolic parameters at baseline were assessed by Spearman’s coefficients. Kaplan–Meier curves were drawn using a ternary approach based on terciles and incident T2D. The association between plasma apolipoproteins concentrations and the incidence of T2D was determined using Cox proportional-hazards models.ResultsDuring a median follow-up of 5-year, 115 participants (37.5%) developed T2D. After adjustment for age, sex, body mass index, FPG, HbA1c, and statin use, the plasma levels of apoC-I, apoC-II, apoC-III, apoE, apoF, apoH, apoJ, and apoL1 were positively associated with a high risk for T2D. After further adjustment for plasma triglycerides, only apoE (1 SD natural-log-transformed hazard ratio: 1.28 [95% confidence interval: 1.06; 1.54]; p = 0.010), apoF (1.22 [1.01; 1.48]; p = 0.037), apoJ (1.24 [1.03; 1.49]; p = 0.024), and apoL1 (1.26 [1.05; 1.52]; p = 0.014) remained significantly associated with the onset of T2D. Kaplan–Meier survival curves also showed that the lower third of plasma apoE levels (< 5.97 mg/dL) was significantly associated with a lower risk of conversion to T2D (log-rank test, p = 0.002) compared to the middle and upper thirds.ConclusionsThe plasma apoE levels are positively associated with the risk of T2D in prediabetes subjects, independently of traditional risk factors. The possible associations of apoF, apoJ, and apoL1 with T2D risk also pave the way for further investigations.Trial registration This trial was registered at clinicaltrials.gov as NCT01218061 and NCT01432509

Presenilin Is Essential for ApoE Secretion, a Novel Role of Presenilin Involved in Alzheimer's Disease Pathogenesis.

Alzheimer's disease (AD) is a debilitating dementia characterized by progressive memory loss and aggregation of amyloid-β (Aβ) protein into amyloid plaques in patient brains. Mutations in presenilin (PS) lead to abnormal generation of Aβ, which is the major cause of familial AD (FAD), and apolipoprotein E4 (ApoE4) is the major genetic risk factor for sporadic AD (SAD) onset. However, whether dysfunction of PS is involved in the pathogenesis of SAD is largely unknown. We found that ApoE secretion was completely abolished in PS-deficient cells and markedly decreased by inhibition of γ-secretase activity. Blockade of γ-secretase activity by a γ-secretase inhibitor, DAPT, decreased ApoE secretion, suggesting an important role of γ-secretase activity in ApoE secretion. Reduced ApoE secretion is also observed in nicastrin-deficient cells with reduced γ-secretase activity. PS deficiency enhanced nuclear translocation of ApoE and binding of ApoE to importin α4, a nuclear transport receptor. Moreover, the expression of PS mutants in PS-deficient cells suppressed the restoration effects on ApoE secretion compared with the expression of wild-type PS. Plasma ApoE levels were lower in FAD patients carrying PS1 mutations compared with normal control subjects. Our findings suggest a novel role of PS contributing to the pathogenesis of SAD by regulating ApoE secretion.SIGNIFICANCE STATEMENT Familial AD (FAD) typically results from mutations in the genes encoding amyloid precursor protein, presenilin 1 (PS1), or PS2. Many PS mutants have been found to exert impaired γ-secretase activity and increased amyloid-β 42 (Aβ42)/Aβ40 ratio, which induce early amyloid deposition and FAD. On the other hand, apolipoprotein E4 (ApoE4) is the major genetic risk factor for sporadic AD (SAD) and contributes to AD pathogenesis because it has reduced Aβ clearance capability compared with ApoE3 and ApoE2. FAD and SAD have long been considered to be caused by these two independent mechanisms; however, for the first time, we demonstrated that PS is essential for ApoE secretion and PS mutants affected ApoE secretion in vitro and in human samples, suggesting a novel mechanism by which PS is also involved in SAD pathogenesis.

Reduced cholesterol efflux capacity of HDL particles from Alzheimer's disease patients is not related to differences in lipoprotein profiles.

High density lipoproteins (HDL) are primarily known for their critical role in regulating cellular cholesterol concentrations via their capacity to induce cholesterol efflux from cells. HDL are also carriers of apolipoprotein E (ApoE), which is the strongest known genetic risk factor for AD. The main objective of this study was to determine the cholesterol efflux capacity of HDL particles isolated from plasma of APOE genotyped AD patients vs. age-matched cognitively normal controls, and to characterize plasma lipoprotein profiles using size exclusion chromatography. HDL particles were isolated from plasma samples of 10 AD patients (n=5 APOE3/E3, n=5 APOE3/E4) and 5 cognitively normal controls (n=5 APOE3/E3) using sequential ultracentrifugation followed by size exclusion chromatography. FPLC chromatograms were processed to adjust baseline values and calculate area under the curve (AUC) for LDL, HDL, and albumin using UNICORN 5.0 software. AUCs were used to estimate the relative distributions of fractions, including small and large HDL, and peak elution volume was used to estimate particle size most abundant in each fraction. Cholesterol efflux capacity of the isolated HDL particles was determined in PBMC-derived macrophages using a fluorescently labeled cholesterol assay kit. HDL from AD patients had dramatically reduced cholesterol efflux capacity compared with controls (36.0% ± 1.2% vs. 26.0% ± 1.2%, P<0.0001), with no difference between AD patients by APOE genotype (APOE3/E3, 25.9% ± 0.9%; APOE3/E4, 26.5% ±1.3%; P=0.21). There were no significant differences in the relative distributions or average particle sizes of HDL, LDL, albumin, or large and small HDL between patients and controls. These results suggest neither the amount nor size distribution of HDL particles is adequate to detect the main difference driving the diminished cholesterol efflux capacity of HDL particles from AD patients. The results of this study support previous findings of decreased cholesterol efflux capacity of HDL in AD patients, and underscore the necessity for additional analyses to characterize the compositional differences driving this diminished functional capacity and to further understand HDL's role in AD pathology.

High Plasma Apolipoprotein(a) Concentration and Low Plasmin Tpa Enzymatic Activity in Hospitalized Patients with COVID-19

Thrombotic and thromboembolic complications in patients diagnosed with coronavirus disease 2019 (COVID-19) are emerging as important sequelae that contribute to mortality, including disseminated intravascular coagulation, pulmonary embolism, deep vein thrombosis, ischemic stroke, and myocardial infraction. Reported incidence of thrombotic and thromboembolic complications in moderate/severe COVID-19 patients is from 21% to 49%, while even higher incidence in non-surviving COVID-19 patients. However, the underlying mechanism between thrombosis and COVID-19 is still unclear.Tissue-type plasminogen activator (tPA) plays an important role on initiating fibrinolysis by converting zymogen plasminogen to plasmin, a serine protease that degrades the fibrin clot, and therefore preventing excessive pathological blood clots. A homologous protein to plasminogen is apolipoprotein(a) [apo(a)], a major component of lipoprotein(a). The apo(a) inhibits fibrinolysis and exacerbates thrombosis through blocking the conversion from Glu-plasminogen to Lys-plasminogen, which has a higher binding affinity to fibrin and is a better substrate to tPA. The population distribution of plasma apo(a) level is positively skewed (most values are clustered around the left tail of the distribution close to zero), and the plasma apo(a) level in most people is less than 300 μg/mL. High plasma concentration of apo(a) (> 300 μg/mL), or genetic variants of LPA, the gene that encodes for apo(a), correlates with thrombotic cardiovascular risk and thromboembolic risk in many population-based clinical or genetic studies. To investigate the potential correlation between infection of SARS-COV-2 and thrombosis, we tested de-identified plasma samples collected from hospitalized patients with or without positivity of SARS-CoV-2 testing results and COVID-19 diagnosis (ICD10CM:U07.1) through the COVD-19 Tissue Bank at the Medical College of Wisconsin. The tPA enzymatic activity was measured by the release of p-nitroaniline chromophore from a plasmin-specific synthetic substrate with exogenous human plasminogen, with the intensity of color proportional to tPA activity. The apo(a) concentration is measured by ELISA capturing total apo(a) antigen.Our results show that the SARS-CoV-2-positive inpatients have higher plasma tPA concentration than the SARS-CoV-2 negative inpatients (6.0 versus 3.0 ng/mL, p<0.05), while plasma tPA enzymatic activity is lower in SARS-CoV-2-positive inpatients than the SARS-CoV-2 negative inpatients (15.2 versus 25.5 ΔA/min/mL/10 4, p<0.0001) (Figure A). The plasma apo(a) concentration is significantly higher in SARS-CoV-2-positive inpatients than in the plasma from SARS-CoV-2-negative inpatients (the median of the two groups are 114.8 versus 34.4 μg/mL, p<0.05) (Figure B). Among the 20 hospitalized patients with COVID-19, 13 survived. The 13 survived patients have one additional plasma sample collected after recovering from COVID-19 (date range between the two blood collections of onset and after recovery is from 19 to 87 days, the mean duration is 42 days). After recovery, 11 out of 13 surviving patients have increased plasma tPA enzymatic activity (the mean value at onset versus recovery is 5.2 versus 7.1 ΔA/min/mL/10 4, p<0.05) (Figure C). Consistently, 11 out of 13 surviving patients have decreased plasma apo(a) concentration compared to the plasma collected during the onset of COVID-19 from the same individuals (the median values of the onset and recovery are 141.1 versus 106.5 μg/mL, p<0.001) (Figure D).In summary, our study shows lower tPA enzymatic activity and higher apo(a) concentration in SARS-CoV-2-positive hospitalized patients compared to SARS-CoV-2-negative hospitalized patients. Among the survived patients, the reduction of apo(a) concentration after recovering from COVID-19 is accordance with the increase of tPA enzymatic activity. Considering the role of apo(a) in inhibiting fibrinolysis through limiting tPA-mediated plasminogen to plasmin conversion, the alteration in apo(a) concentration provide a possible explanation of change of tPA activity in patients with severe COVID-19. [Display omitted] DisclosuresBaumann Kreuziger: CSL Behring: Consultancy; Quercegen Pharmaceuticals: Consultancy; Vaccine Injury Compensation Program: Consultancy.

Dietary-Induced Elevations of Triglyceride-Rich Lipoproteins Promote Atherosclerosis in the Low-Density Lipoprotein Receptor Knockout Syrian Golden Hamster.

Elevated triglycerides are associated with an increased risk of cardiovascular disease (CVD). Therefore, it is very important to understand the metabolism of triglyceride-rich lipoproteins (TRLs) and their atherogenic role in animal models. Using low-density lipoprotein receptor knockout (LDLR−/−) Syrian golden hamsters, this study showed that unlike LDLR−/− mice, when LDLR−/− hamsters were fed a high cholesterol high-fat diet (HFD), they had very high plasma levels of triglycerides and cholesterol. We found that LDLR−/− hamsters exhibited increased serum TRLs and the ApoB100 and 48 in these particles after being fed with HFD. Treatment with ezetimibe for 2 weeks decreased these large particles but not the LDL. In addition, ezetimibe simultaneously reduced ApoB48 and ApoE in plasma and TRLs. The expression of LRP1 did not change in the liver. These findings suggested that the significantly reduced large particles were mainly chylomicron remnants, and further, the remnants were mainly cleared by the LDL receptor in hamsters. After 40 days on an HFD, LDLR−/− hamsters had accelerated aortic atherosclerosis, accompanied by severe fatty liver, and ezetimibe treatment reduced the consequences of hyperlipidemia. Compared with the serum from LDLR−/− hamsters, that from ezetimibe-treated LDLR−/− hamsters decreased the expression of vascular adhesion factors in vascular endothelial cells and lipid uptake by macrophages. Our results suggested that in the LDLR−/− hamster model, intestinally-derived lipoprotein remnants are highly atherogenic and the inflammatory response of the endothelium and foam cells from macrophages triggered atherosclerosis. The LDL receptor might be very important for chylomicrons remnant clearance in the Syrian golden hamster, and this may not be compensated by another pathway. We suggest that the LDLR−/− hamster is a good model for the study of TRLs-related diseases as it mimics more complex hyperlipidemia.

HDL (High-Density Lipoprotein) Subspecies, Prevalent Covert Brain Infarcts, and Incident Overt Ischemic Stroke: Cardiovascular Health Study.

Whether HDL (high-density lipoprotein) is associated with risk of vascular brain injury is unclear. HDL is comprised of many apo (apolipoprotein) species, creating distinct subtypes of HDL. We utilized sandwich ELISA to determine HDL subspecies from plasma collected in 1998/1999 from 2001 CHS (Cardiovascular Health Study) participants (mean age, 80 years). In cross-sectional analyses, participants with higher apoA1 in plasma and lower apoE in HDL were less likely to have prevalent covert magnetic resonance imaging-defined infarcts: odds ratio for apoA1 Q4 versus Q1, 0.68 (95% CI, 0.50-0.93), and odds ratio for apoE Q4 versus Q1, 1.36 (95% CI, 1.01-1.84). Similarly, apoA1 in the subspecies of HDL that lacked apoC3, apoJ, or apoE was inversely related to covert infarcts, and apoE in the subspecies of HDL that lacked apoC3 or apoJ was directly related to covert infarcts in prospective analyses. In contrast, the concentrations of apoA1 and apoE in the complementary subspecies of HDL that contained these apos were unrelated to covert infarcts. Patterns of associations between incident overt ischemic stroke and apoA1, apoE, and apoA1 and apoE in subspecies of HDL were similar to those observed for covert infarcts but less pronounced. This study highlights HDL subspecies defined by apo content as relevant biomarkers of covert and overt vascular brain injury.

PCSK9 inhibition with alirocumab decreases plasma lipoprotein(a) concentration by a dual kinetic mechanism of action

Abstract Background Lipoprotein(a) [Lp(a)] is a low-density lipoprotein (LDL)-like particle, covalently bound to apolipoprotein(a) [apo(a)]. Recent trials show that proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, such as alirocumab, decrease plasma Lp(a) levels and risk of atherosclerotic cardiovascular disease (ASCVD). The kinetic mechanism for lowering Lp(a) by PCSK9 inhibitors may differ according to pre-treatment apo(a) levels. Purpose We investigated the effect of alirocumab on Lp(a) metabolism in 21 long-term statin-treated patients [Lp(a) &amp;gt;0.5 g/L in all] with moderate-high (n=10) and high (n=11) apo(a) concentrations according to a cutoff of median apo(a) levels of 145 nmol/L. Methods Apo(a) kinetics were studied before and after 12-week treatment with alirocumab (150 mg subcutaneously fortnightly). Apo(a) fractional catabolic rate (FCR) and production rate (PR) were determined using intravenous D3-leucine administration, mass spectrometry and compartmental modelling. Results The plasma concentration and PR of apo(a) were significantly higher in patients with high apo(a) than in patients with moderate-high apo(a) levels (273±30 nmol/L vs 130±4.7 nmol/L and 6.0±0.69 nmol/kg/day vs 2.6±0.15 nmol/kg/day, respectively; P&amp;lt;0.001). The FCR of apo(a) was not significantly different between two groups (0.48±0.02 pools/day vs 0.45±0.01 pools/day, P&amp;gt;0.05). In patients with moderate-high apo(a) levels, alirocumab significantly lowered plasma apo(a) levels (−17%, P&amp;lt;0.01) and increased the FCR of apo(a) (+26%, P&amp;lt;0.001), but did not alter apo(a) PR. In contrast, alirocumab significantly lowered plasma apo(a) concentrations (−31%, P&amp;lt;0.001) via a dual mechanism that increased apo(a) FCR (+31%, P&amp;lt;0.001) and lowered PR (−9%, P&amp;lt;0.05) in patients with high apo(a) levels. The reductions in apo(a) concentration and PR with alirocumab in the high apo(a) group remained significant after adjusting for background statin when compared with patients with moderate-high apo(a) levels (P&amp;lt;0.05). Conclusions In statin-treated patients with elevated Lp(a), alirocumab may lower elevated plasma Lp(a) concentrations by a dual mechanism of increasing the catabolism and decreasing the production of Lp(a) particles, specifically in patients with relatively high apo(a) concentrations. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This independent research was funded by an Investigator Initiated Study Concept Research Grant from Regeneron Pharmaceuticals and Sanofi (Protocol No. LPS 14508). Figure 1Figure 2

Effects of COVID-19 and diabetes mellitus on apolipoprotein A1 level in the blood plasma of patients

Background. Increased level of high-density lipoprotein (HDL) cholesterol and apolipoprotein A1 (ApoA1) in plasma is associated with a reduced risk of developing cardiovascular diseases. In addition to its potential cardioprotective function, HDL and ApoA1, the main HDL apolipoprotein, also have antidiabetic properties. The aim of the study was to determine the level of ApoA1 in the blood of patients (n = 81) with diabetes mellitus and COVID-19. Materials and methods. ApoA1 was determined by enzyme-linked immunosorbent assay kits (Elabscience, USA). The measurements were performed at an optical density of 450 nm. Results. ApoA1 level in the blood of patients with diabetes and especially with COVID-19 was significantly lower than in healthy people. The study of the dependence of plasma ApoA1 content on the level of Hb1Ac, the gender and the type of diabetes showed that in blood of patients with type 2 diabetes the amount of ApoA1 is lower than in those with type 1 diabetes, and with an increase in the level of Hb1Ac the amount of ApoA1 decreases. There was also significant gender difference. With an increase in the body mass index, the content of ApoA1 in blood plasma decreases below normal — 0.9 g/L, and at body mass index &lt; 25 kg/m2, the amount of ApoA1 is significantly higher than the average lipoprotein level in diabetic patients. In individuals with newly diagnosed diabetes, the level of ApoA1 is significantly higher, and in patients with more than 10 years of illness, it is below average and below normal. Biguanide treatment, either in combination with other drugs (mainly insulin) or as monothe-rapy, does not significantly affect the level of ApoA1 compared to the entire group average. In patients treated with sulfonylurea, the level of ApoA1 is significantly lower than the average level for the group and the norm. A significant positive effect on the amount of ApoA1 in plasma was observed in people treated with a combination of drugs with sodium-glucose cotransporter type 2 inhibitors, insulin and especially dipeptidyl peptidase-4 inhibitors. However, insulin monotherapy did not significantly affect the ApoA1 content. Possible mechanisms of ApoA1 decrease in COVID-19 and diabetes are discussed. Conclusions. Thus, the level of ApoA1 may be one of the promising markers of severe COVID-19.

The effect of the content of ApoA-I in peripheral blood on the state of immune homeostasis in people living in extreme climatic conditions of the Arctic.

The paper presents data on the impacts of the content of ApoA-I in peripheral blood on the state of immune homeostasis in people living in extreme climatic conditions of the Arctic. From the village of Revda, Murmansk region, 191 people were examined, 160 women and 31 men, aged from 21 to 55 years. The analysis of the results was carried out depending on the level of ApoA-I content: 111 examined people had a low content of ApoA-I (< 115 mg/dl) and 80 people had a concentration of ApoA-I - within the physiological norm (115-220 mg/dl). Deficiency of ApoA-I is associated with an increase in plasma concentrations of total cholesterol in 37.5% and triglycerides in 62.5% of cases. Low content of ApoA-I is associated with a decrease in the content of neutrophilic granulocytes and an increase in the concentration of small lymphocytes, IL-10 and IgE. Deficiency of ApoA-I is associated with an increase in the content of CD45RA+, CD16+, CD56+ lymphocyte phenotypes in blood. Low concentrations of ApoA-I are associated with low expression activity of L-selectin gene and free L-selectin ligand. Due to deficiency of ApoA-I, no significant differences were detected in the content of transferrin, free transferrin receptor, haptoglobin, free calcium-dependent cell adhesion protein, and free pool of receptors involved in apoptosis. Conclusion: deficiency of ApoA-I in blood plasma is associated with increased migration of neutrophils into the tissue and cell-mediated cytotoxicity of lymphocytes and occurs because of the effect of decreased activity of the level of antioxidant defense, changes in the structure of cell membranes and the participation of adhesion molecules.

861Mendelian randomization on habitual coffee intake and plasma lipid profile: evidence from UK Biobank

Abstract Background Long-term heavy coffee consumption may adversely affect individuals’ cardiovascular disease (CVD) risk. As hyperlipidemia is a well-established contributor to CVD, we investigated the association between habitual coffee intake and plasma lipid profile. Methods We used data from up to 362,571 UK Biobank participants to examine associations between coffee intake and plasma lipid profiles, including LDL-C, HDL-C, total-C, triglycerides, ApoA1 and ApoB. Inverse variance weighted mendelian randomization (MR) was used to interrogate the causal nature of coffee-lipid associations, complemented by pleiotropy-robust methods, including MR-median, MR-Mode, MR-PRESSO and MR-Egger. Results We observed positive dose-dependent associations between self-reported coffee intake and plasma concentration of LDL-C, ApoB and total-C, with the highest lipid levels seen among participants drinking &amp;gt;6 cups/day (Plinear trend≤1.97E-57 for all). Genetic instrument for coffee intake was robustly associated with self-reported intake in the UK Biobank (F-statistic = 416). One cup increase in genetically instrumented intake was associated with 0.07 mmol/L (95%CI 0.03 to 0.12), 0.02 g/L (95%CI 0.01 to 0.03), and 0.09 mmol/L (95%CI 0.04 to 0.14) increase in LDL-C, ApoB, and total-C, respectively. Pleiotropy-robust methods provided largely consistent results albeit with greater imprecision when using MR-Egger. Conclusions Our phenotypic and genetic analysis consistently suggests that long-term heavy coffee consumption can lead to unfavourable lipid profile, which could potentially increase individuals’ risk for CVD. Individuals with elevated cholesterol may need to reduce their daily coffee intake. Key messages Our study provides evidence that long-term heavy coffee consumption can lead to unfavourable lipid profile.

Impact of C-Reactive Protein on Cognition and Alzheimer Disease Biomarkers in Homozygous APOE ɛ4 Carriers.

Previous research has shown that elevated blood C-reactive protein (CRP) is associated with increased Alzheimer disease (AD) risk only in APOE ε4 allele carriers; the objective of this study was to examine the interactive effects of plasma CRP and APOE genotype on cognition and AD biomarkers. Data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) study were analyzed, including APOE genotype; plasma CRP concentrations; diagnostic status (i.e., mild cognitive impairment and dementia due to AD); Mini-Mental State Examination (MMSE) and Clinical Dementia Rating Dementia Staging Instrument scores; CSF concentrations of β-amyloid peptide (Aβ42), total tau (t-Tau) and phosphorylated tau (p-Tau); and amyloid (AV45) PET imaging. Multivariable regression analyses tested the associations between plasma CRP and APOE on cognitive and biomarker outcomes. Among 566 ADNI participants, 274 (48.4%) had no, 222 (39.2%) had 1, and 70 (12.4%) had 2 APOE ε4 alleles. Among only participants who had 2 APOE ε4 alleles, elevated CRP was associated with lower MMSE score at baseline (β [95% confidence interval] -0.52 [-1.01, -0.12]) and 12-month follow-up (β -1.09 [-1.88, -0.17]) after adjustment for sex, age, and education. The interaction of 2 APOE ε4 alleles and elevated plasma CRP was associated with increased CSF levels of t-Tau (β = 11.21, SE 3.37, p < 0.001) and p-Tau (β = +2.74, SE 1.14, p < 0.01). Among those who had no APOE ε4 alleles, elevated CRP was associated with decreased CSF t-Tau and p-Tau. These effects were stronger at the 12-month follow-up. CRP released during peripheral inflammation could be a mediator in APOE ε4-related AD neurodegeneration and serve as a drug target for AD.

The association between apolipoprotein A-1 plasma level and premature coronary artery disease: A systematic review and meta-analysis.

Apolipoprotein A-1 (Apo A-1) is a constituent of high-density lipoprotein (HDL) and emerging evidences put forward a potential association between Apo A-1 plasma levels and premature coronary artery disease (pCAD). The aim of the present study is to gather relative literature and perform a systematic review and meta-analysis regarding the association between serum ApoA-1 levels and pCAD. Medline (via PubMed), Scopus, Embase and Web of Science databases were searched from the inception of databases until December 7, 2020. All articles reporting the plasma levels of ApoA-1 in patients with pCAD and the control group were included. A meta-analysis with pooled standardised mean difference (SMD) and 95% confidence interval (95% CI) was reported. Subgroup analyses were done based on the observed heterogeneity in results. Seventeen case-control studies were included. ApoA-1 plasma level was calculated to be lower in pCAD patients compared with the control group (SMD: -0.67; 95% CI: -0.48 to -0.86; P < .001). The subgroup analysis and meta-regression showed that the variation in gender distribution, the development level of the target population's country and quality score of included studies were the main sources of heterogeneity. It was observed that the relationship was only significant in the developed countries (P < .001). Also, the heterogeneity was reduced when the analysis was limited to males (I2 = 57.2%) and females only (I2 = 26.0%). In conclusion, there seems to be a significant association between the serum levels of ApoA-1 and pCAD. However, all of the included studies had a case-control design and since there is no good quality and prospective cohort studies included, reliability of the current evidence is debatable. Therefore, further well-designed cohort studies are required to assess the impact of serum ApoA-1 reduction on pCAD onset.

Apolipoprotein B/A1 ratio as a potential marker of cardiovascular risk in women

Background: There has been a significant steady rise in the prevalence of cardiovascular disease (CVD) among Nigerian women within the last decade. The balance between pro-atherogenic particles and antiatherogenic particles has been markedly reflected in the apolipoprotein B/A1 ratio (Apo B/A1), and this ratio has been shown to be the strongest single lipoprotein-related cardiovascular risk factor. The cutoff value for the apo B/A1 ratio that defines high cardiovascular risk has been proposed to be 0.8 for women. This study is to determine the apo B/A1 ratio in apparently healthy Nigerian women and to evaluate the relationship of this ratio with other lipid indices. Methods: A total of 161 apparently healthy female adults between the ages of 30 and 66 years were selected for this study over a period of 6 months. Plasma total cholesterols (TC), triglycerides (TG), and high-density lipoprotein cholesterol (HDL-C) were measured using the enzymatic methods, whereas low-density lipoprotein cholesterol (LDL-C) was calculated using the Friedewald formula. Apolipoprotein A1 and B were determined using immunoturbidimetry methods. Results: The mean of plasma apo B/A-I ratio in the studied participants was 0.68, with values ranging from 0.27 to 1.46. The percentage of participants with the apoB/apoA-I ratio exceeding 0.8 (the cutoff value for CVD risk) was 24.2%. The participants with apoB/apoA-I &gt;0.8 were characterized by higher mean TC (216 mg/dl vs. 171 mg/dl; P &lt; 0.001), TG (80 mg/dl vs. 66 mg/dl; P = 0.007), LDL-C (163 mg/dl vs. 120 mg/dl; P &lt; 0.001), and lower HDL-C (36 mg/dl vs. 43 mg/dl; P &lt; 0.001) compared with women with apoB/apoA-I &lt; 0.8. Conclusion: This study has demonstrated that the women with apo B/A1 &gt;0.8 have worse atherogenic lipid profile (high plasma TC, TG, low-density lipoprotein cholesterol, and low high-density cholesterol). It has also shown that only the apoB/A-I ratio correlates with other lipid markers; it should be considered as a potential useful tool in cardiovascular risk assessment in women. Its potential use in the national guideline for assessment and management of dyslipidemia will be invaluable.

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.

Olanzapine leads to nonalcoholic fatty liver disease through the apolipoprotein A5 pathway

The antipsychotic drug olanzapine was reported to induce nonalcoholic fatty liver disease (NAFLD), whereas the underlying mechanism remains incompletely understood. This study investigated whether apolipoprotein A5 (apoA5) and sortilin, two interactive factors involved in NAFLD pathogenesis, are implicated in olanzapine-induced NAFLD. In our study, at week 8, olanzapine treatment successfully induced hepatic steatosis in female C57 BL/6 J mice, which was independent of body weight gain. Likewise, olanzapine effectively mediated hepatocyte steatosis in HepG2 cells characterized by substantially elevated intracellular lipid droplets. Increased plasma triglyceride concentration and decreased plasma apoA5 levels were observed in mice treated with 8-week olanzapine. Surprisingly, olanzapine markedly enhanced hepatic apoA5 protein levels in mice, without a significant effect on rodent hepatic ApoA5 mRNA. Our in vitro study showed that olanzapine reduced apoA5 protein levels in the medium and enhanced apoA5 protein levels in hepatocytes, whereas this drug exerted no effect on hepatocyte APOA5 mRNA. By transfecting APOA5 siRNA into HepG2 cells, it was demonstrated that APOA5 knockdown effectively reversed olanzapine-induced hepatocyte steatosis in vitro. In addition, olanzapine drastically increased sortilin mRNA and protein levels in vivo and in vitro. Interestingly, SORT1 knockdown reduced intracellular apoA5 protein levels and increased medium apoA5 protein levels in vitro, without affecting intracellular APOA5 mRNA levels. Furthermore, SORT1 knockdown greatly ameliorated hepatocyte steatosis in vitro. This study provides the first evidence that sortilin inhibits the hepatic apoA5 secretion that is attributable to olanzapine-induced NAFLD, which provides new insight into effective strategies against NAFLD for patients with schizophrenia administered olanzapine.