Apolipoprotein B Research Articles

Novel oxidized LDL-based clinical markers in peritoneal dialysis patients for atherosclerosis risk assessment

Maintenance peritoneal dialysis (PD) is commonly associated with cardiovascular diseases (CVDs), whose risk is assessed via LDL-C. Nonetheless, oxidized LDL (oxLDL), as being a key component of atherosclerotic lesions, could be also associated with atherosclerosis and related CVDs. However, its predictive value for CVDs risk assessment is subject of research studies due to the lack of specific methods to measure oxLDL status from its individual lipid/protein components. In the present study, six novel oxLDL markers, representative of certain oxidative modifications on the LDL protein and lipid components, are measured in atherosclerosis-prone PD patients (39) versus those in chronic kidney disease patients (61) under hemodialysis (HD) and healthy controls (40). LDL from serum of PD, HD and control subjects were isolated and fractionated into cholesteryl esters, triglycerides, free cholesterol, phospholipids and apolipoprotein B100 (apoB100). Subsequently the oxLDL markers cholesteryl ester hydroperoxides (-OOH), triglyceride-OOH, free cholesterol-OOH, phospholipid-OOH, apoB100 malondialdehyde and apoB100 dityrosines were measured. LDL carotenoid levels and LDL particle serum concentration were also measured. The levels of all oxLDL lipid-OOH markers were significantly elevated in PD patients versus control, while the levels of cholesteryl ester-/triglyceride-/free cholesterol-OOH were significantly elevated in PD versus HD patients, regardless of patients’ underlying medical conditions, sex, age, PD type, clinical biochemical markers and medication. It should be noted that all fractionated lipid-OOH levels were inversely correlated with LDL-P concentration, while LDL-P concentration was not correlated with LDL-C in PD patients. Moreover, LDL carotenoids were significantly lower in PD patients versus control. The increased levels of oxLDL status specific markers in both PD and HD patients (compared to control), support a potential prognostic value of oxLDL regarding CVD risk assessment in both patient groups. Lastly, the study introduces the oxLDL peroxidation markers free cholesterol-OOH and cholesteryl ester-OOH as complementary to LDL-P number, and as possible alternatives to LDL-C.

Reducing Premature Coronary Artery Disease in Malaysia by Early Identification of Familial Hypercholesterolemia Using the Familial Hypercholesterolemia Case Ascertainment Tool (FAMCAT): Protocol for a Mixed Methods Evaluation Study.

Familial hypercholesterolemia (FH) is predominantly caused by mutations in the 4 FH candidate genes (FHCGs), namely, low-density lipoprotein receptor (LDLR), apolipoprotein B-100 (APOB-100), proprotein convertase subtilisin/kexin type 9 (PCSK9), and the LDL receptor adaptor protein 1 (LDLRAP1). It is characterized by elevated low-density lipoprotein cholesterol (LDL-c) levels leading to premature coronary artery disease. FH can be clinically diagnosed using established clinical criteria, namely, Simon Broome (SB) and Dutch Lipid Clinic Criteria (DLCC), and can be identified using the Familial Hypercholesterolemia Case Ascertainment Tool (FAMCAT), a primary care screening tool. This study aims to (1) compare the detection rate of genetically confirmed FH and diagnostic accuracy between the FAMCAT, SB, and DLCC in the Malaysian primary care setting; (2) identify the genetic mutation profiles, including novel variants, in individuals with suspected FH in primary care; (3) explore the experience, concern, and expectation of individuals with suspected FH who have undergone genetic testing in primary care; and (4) evaluate the clinical utility of a web-based FH Identification Tool that includes the FAMCAT, SB, and DLCC in the Malaysian primary care setting. This is a mixed methods evaluation study conducted in 11 Ministry of Health primary care clinics located at the central administrative region of Malaysia. In Work stream 1, the diagnostic accuracy study design is used to compare the detection rate and diagnostic accuracy of the FAMCAT, SB, and DLCC against molecular diagnosis as the gold standard. In Work stream 2, the targeted next-generation sequencing of the 4 FHCGs is used to identify the genetic mutation profiles among individuals with suspected FH. In Work stream 3a, a qualitative semistructured interview methodology is used to explore the experience, concern, and expectation of individuals with suspected FH who have undergone genetic testing. Lastly, in Work stream 3b, a qualitative real-time observation of primary care physicians using the "think-aloud" methodology is applied to evaluate the clinical utility of a web-based FH Identification Tool. The recruitment for Work stream 1, and blood sampling and genetic analysis for Work stream 2 were completed in February 2023. Data collection for Work stream 3 was completed in March 2023. Data analysis for Work streams 1, 2, 3a, and 3b is projected to be completed by June 2023, with the results of this study anticipated to be published by December 2023. This study will provide evidence on which clinical diagnostic criterion is the best to detect FH in the Malaysian primary care setting. The full spectrum of genetic mutations in the FHCGs including novel pathogenic variants will be identified. Patients' perspectives while undergoing genetic testing and the primary care physicians experience in utilizing the web-based tool will be established. These findings will have tremendous impact on the management of patients with FH in primary care and subsequently reduce their risk of premature coronary artery disease. DERR1-10.2196/47911.

Study on the prediction model of atherosclerotic cardiovascular disease in the rural Xinjiang population based on survival analysis

PurposeWith the increase in aging and cardiovascular risk factors, the morbidity and mortality of atherosclerotic cardiovascular disease (ASCVD), represented by ischemic heart disease and stroke, continue to rise in China. For better prevention and intervention, relevant guidelines recommend using predictive models for early detection of ASCVD high-risk groups. Therefore, this study aims to establish a population ASCVD prediction model in rural areas of Xinjiang using survival analysis.MethodsBaseline cohort data were collected from September to December 2016 and followed up till June 2022. A total of 7975 residents (4054 males and 3920 females) aged 30–74 years were included in the analysis. The data set was divided according to different genders, and the training and test sets ratio was 7:3 for different genders. A Cox regression, Lasso-Cox regression, and random survival forest (RSF) model were established in the training set. The model parameters were determined by cross-validation and parameter tuning and then verified in the training set. Traditional ASCVD prediction models (Framingham and China-PAR models) were constructed in the test set. Different models' discrimination and calibration degrees were compared to find the optimal prediction model for this population according to different genders and further analyze the risk factors of ASCVD.ResultsAfter 5.79 years of follow-up, 873 ASCVD events with a cumulative incidence of 10.19% were found (7.57% in men and 14.44% in women). By comparing the discrimination and calibration degrees of each model, the RSF showed the best prediction performance in males and females (male: Area Under Curve (AUC) 0.791 (95%CI 0.767,0.813), C statistic 0.780 (95%CI 0.730,0.829), Brier Score (BS):0.060, female: AUC 0.759 (95%CI 0.734,0.783) C statistic was 0.737 (95%CI 0.702,0.771), BS:0.110). Age, systolic blood pressure (SBP), apolipoprotein B (APOB), Visceral Adiposity Index (VAI), hip circumference (HC), and plasma arteriosclerosis index (AIP) are important predictors of ASCVD in the rural population of Xinjiang.ConclusionThe performance of the ASCVD prediction model based on the RSF algorithm is better than that based on Cox regression, Lasso-Cox, and the traditional ASCVD prediction model in the rural population of Xinjiang.

Repetitive Antigen Responses of LDL-Reactive CD4+ T Cells Induce Tr1 Cell-Mediated Immune Tolerance.

Inflammation triggered by the deposition of LDL (low-density lipoprotein) in the arterial wall leads to the development of atherosclerosis. Regulatory T (Treg) cells inhibit vascular inflammation through the induction of immune tolerance toward LDL-related antigens. However, tolerogenic mechanisms that promote the generation of LDL-specific Treg cells in vivo remain unclear. We identified LDL-specific T cells by activation-induced marker expression and analyzed expression profiles and suppressive functions of TCR (T-cell antigen receptor)-transgenic T cells upon repetitive transfer into antigen-transgenic mice via flow cytometry. We investigated the naturally occurring Treg-cell response against human LDL in standard chow diet-fed mice that are transgenic for human ApoB100 (apolipoprotein B100). We found that IL (interleukin)-10 expression in LDL-specific T cells from spleen increases with age, albeit LDL-specific populations do not enlarge in older mice. To investigate the generation of IL-10-producing LDL-specific T cells, we transferred naive CD4+ T cells recognizing human ApoB100 from TCR-transgenic mice into human ApoB100-transgenic mice. Adoptive transfer of human ApoB100-specific T cells induced immune tolerance in recipient mice and effectively inhibited activation of subsequently transferred naive T cells of the same specificity in vivo. Moreover, repetitive transfers increased the population of Treg type 1 cells that suppress ApoB100-specific responses via IL-10. In a translational approach, LDL-specific Treg type 1 cells from blood of healthy donors suppressed the activation of monocytic THP-1 cells in an IL-10-dependent manner. We show that repetitive transfer of naive ApoB100-specific T cells and recurrent LDL-specific T-cell stimulation induces Treg type 1 cell-mediated immune tolerance against LDL in vivo. Our results provide insight into the generation of autoantigen-specific anti-inflammatory T cells under tolerogenic conditions.

Association between serum apolipoprotein A1 and atrial fibrillation in the Chinese population: a case–control study

BackgroundThe relationship between serum apolipoprotein A1 (APOA1) and atrial fibrillation (AF) is not known. Therefore, we sought to investigate the associations between APOA1 and AF in the Chinese population.MethodsThis case–control study included 950 patients with AF (29–83 years old, 50.42% male) who were hospitalized consecutively in China between January 2019 and September 2021. Controls with sinus rhythm and without AF were matched (1:1) to cases by sex and age. Pearson correlation analysis was performed to investigate the correlation between APOA1 and blood lipid profiles. Multivariate regression models were used to explore the association between APOA1 and AF. The receiver operator characteristic (ROC) curve was constructed to examine the performance of APOA1.ResultsMultivariate regression analysis showed that low serum APOA1 in men and women with AF was significantly associated with AF (OR = 0.261, 95% CI: 0.162–0.422, P < 0.001). Pearson correlation analysis indicated that serum APOA1 was positively correlated with total cholesterol (TC) (r = 0.456, p < 0.001), low-density lipoprotein cholesterol (LDL-C) (r = 0.825, p < 0.001), high-density lipoprotein cholesterol (HDL-C) (r = 0.238, p < 0.001), and apolipoprotein B (APOB) (r = 0.083, p = 0.011). ROC curve analysis showed that APOA1 levels of 1.105 g/L and 1.205 g/L were the optimal cut-off values for predicting AF in males and females, respectively.ConclusionLow APOA1 in male and female patients is significantly associated with AF in the Chinese population of non-statin users. APOA1 may be a potential biomarker for AF and contribute to the pathological progression of AF along with low blood lipid profiles. Potential mechanisms remain to be further explored.

Expanded presentation of Lyme autoantigens and identification of a novel immunogenic CD4+ T cell epitope from Borrelia burgdorferiMCP4 in murine Lyme arthritis

Abstract Lyme arthritis (LA), caused by Borrelia burgdorferi (Bb), is often accompanied by autoimmune T and B cell responses, but the mechanisms of infection-induced autoimmunity are unclear. We used an immunopeptidomics approach to identify potential Lyme autoantigens and immunogenic Bb antigens, which were validated by histology and testing of T cell reactivity. C57BL/6 (B6) mice, which develop mild inflammatory LA, and B6 Il10−/− (IL10 KO) mice, which develop severe, persistent LA, were infected with Bb for 4 or 16 weeks, and MHCII-bound peptides from inguinal and popliteal lymph nodes were identified by LC-MS/MS. Joint inflammation, fibrosis, and vascular remodeling were analyzed by H&amp;E, Masson’s trichrome, and anti-CD31 immunohistochemistry, respectively. Six Bb peptides were identified by LC-MS/MS, of which one epitope from methyl-accepting chemotaxis protein 4 (MCP4) was an immunogenic CD4+ T cell antigen. Over 10,000 self peptides, particularly from proteins involved in cholesterol metabolism, tissue damage, and vascular inflammation were identified in infected mice. Presentation of peptides from previously identified human Lyme autoantigens apolipoprotein B-100, fibronectin, and type V collagen were expanded in infected mice, suggestive of epitope spreading. Consistent with immunopeptidomics data, joints showed increased inflammatory infiltrate, fibrosis and neovascularization in infected mice, compared with joints from uninfected mice. In conclusion, this immunopeptidomics approach revealed key insights into potential mechanisms of infection-induced autoimmunity in LA and indentified a novel immunogenic CD4+ T cell antigen from Bb MCP4. Supported by grants from NIAID (R21AI148982)

Additive Effect of APOE Rare Variants on the Phenotype of Familial Hypercholesterolemia.

Autosomal dominant hypercholesterolemia (ADH) is due to deleterious variants in LDLR, APOB, or PCSK9 genes. Double heterozygote for these genes induces a more severe phenotype. More recently, a new causative variant of heterozygous ADH was identified in APOE. Here we study the phenotype of 21 adult patients, double heterozygotes for rare LDLR and rare APOE variants (LDLR+APOE) in a national wide French cohort. LDLR, APOB, PCSK9, and APOE genes were sequenced in 5743 probands addressed for ADH genotyping. The lipid profile and occurrence of premature atherosclerotic cardiovascular diseases were compared between the LDLR+APOE carriers (n=21) and the carriers of the same LDLR causative variants alone (n=22). The prevalence of LDLR+APOE carriers in this French ADH cohort is 0.4%. Overall, LDL (low-density lipoprotein)-cholesterol concentrations were 23% higher in LDLR+APOE patients than in LDLR patients (9.14±2.51 versus 7.43±1.59 mmol/L, P=0.0221). When only deleterious or probably deleterious variants were considered, the LDL-cholesterol concentrations were 46% higher in LDLR+APOE carriers than in LDLR carriers (10.83±3.45 versus 7.43±1.59 mmol/L, P=0.0270). Two patients exhibited a homozygous familial hypercholesterolemia phenotype (LDL-cholesterol >13 mmol/L). Premature atherosclerotic cardiovascular disease was more common in LDLR+APOE patients than in LDLR carriers (70% versus 30%, P=0.026). Although an incomplete penetrance should be taken into account for APOE variant classification, these results suggest an additive effect of deleterious APOE variants on ADH phenotype highlighting the relevance of APOE sequencing.

Metabolic profile in women with bulimia nervosa or binge-eating disorder before and after treatment: secondary analysis from the randomized PED-t trial

PurposeChaotic eating and purging behavior pose a risk to the metabolic health of women with bulimia nervosa (BN) and binge-eating disorder (BED). This study reports on one-year changes in blood markers of metabolic health and thyroid hormones in women with BN or BED attending two different treatments.MethodsThese are secondary analyses from a randomized controlled trial of 16-week group treatment of either physical exercise and dietary therapy (PED-t) or cognitive behavior therapy (CBT). Blood samples collected at pre-treatment, week eight, post-treatment, and at 6- and 12-month follow-ups were analyzed for glucose, lipids (triglycerides (TG), total cholesterol (TC), LDL cholesterol (LDL-c), HDL cholesterol (HDL-c), apolipoprotein A (ApoA) and apolipoprotein B (ApoB) lipoproteins), and thyroid hormones (thyroxine (T4), thyroid stimulating hormone (TSH), and thyroperoxidase antibodies).ResultThe average levels of blood glucose, lipids and thyroid hormones were within the recommended range, but clinical levels of TC and LDL-c were detected in 32.5% and 39.1%, respectively. More women with BED compared with BN had low HDL-c, and a larger increase over time in TC and TSH. No significant differences occurred between PED-t and CBT at any measurement. Exploratory moderator analyses indicated a more unfavorable metabolic response at follow-up among treatment non-responders.ConclusionThe proportion of women with impaired lipid profiles and unfavorable lipid changes, suggests active monitoring with necessary management of the metabolic health of women with BN or BED, as recommended by metabolic health guidelines.Level of evidence: Level I: Evidence obtained from a randomized, experimental trial.Trial registration number: This trial was prospectively registered in the Norwegian Regional Committee for Medical and Health Research Ethics on December 16, 2013, with the identifier number 2013/1871, and in Clinical Trials on February 17, 2014, with the identifier number NCT02079935.

Healthy astrocytes provide neuroprotection against apolipoprotein B-100-induced motor neuron degeneration (P10-8.001)

<h3>Objective:</h3> To investigate the role of astrocytes in apolipoprotein B-100 (ApoB)-mediated motor neuron degeneration in sporadic amyotrophic lateral sclerosis (ALS). <h3>Background:</h3> ALS is a devastating neurodegenerative disease which results in motor neuron degeneration in the brain and spinal cord. Our previous research identified ApoB as a neurotoxic factor as it is upregulated in the cerebrospinal fluid (CSF) of ALS patients and can induce motor disability and motor neuron degeneration <i>in vivo</i> in mice, as well as death of human motor neurons <i>in vitro</i>. Here, we investigate whether astrocytes play a role in exacerbating or protecting against ApoB-induced motor neuron death. <h3>Design/Methods:</h3> Primary human astrocytes were plated on matrigel/DMEM-F12-coated chamber slides and grown in astrocyte growth media (AGM) overnight. The next day, the AGM was replaced with motor neuron maintenance media (MNMM) and iPSC-derived human motor neurons were plated directly on top of the astrocytes or on coated slides without astrocytes. On day 9, cells were either treated with 1 ng/μL ApoB diluted in MNMM or 50% ALS CSF/MNMM. Twenty-four hours later cells were fixed in 4% PFA for ChAT and ApoB immunocytochemistry. <h3>Results:</h3> ALS CSF and ApoB induce human motor neuron degeneration, as indicated by significantly smaller ChAT⁺ clusters compared to the media cultures. In contrast, ALS CSF and ApoB have no effect on the size of ChAT⁺ motor neuron clusters co-cultured with human astrocytes. ApoB staining intensity on ApoB-treated motor neurons is significantly reduced in the co-cultures vs. monocultures. <h3>Conclusions:</h3> Healthy astrocytes appear to protect motor neurons from the neurotoxic effects of ApoB by reducing uptake of ApoB into motor neurons. This suggests that intrinsic defects in ALS astrocytes disrupt this neuroprotective function, leaving motor neurons susceptible to ApoB-mediated degeneration. Future experiments will seek to elucidate how astrocyte dysfunction contributes to motor neuron degeneration in ALS. <b>Disclosure:</b> Ms. Griffin has nothing to disclose. Miss Gao has nothing to disclose. Dr. Wong has nothing to disclose. Dr. Sadiq has nothing to disclose.

Bax inhibitor protects against apolipoprotein B-100-induced human motor neuron degeneration in vitro (P10-8.002)

<h3>Objective:</h3> To investigate whether apolipoprotein B-100 (ApoB) in sporadic amyotrophic lateral sclerosis (sALS) cerebrospinal fluid (CSF) induces motor neuron death through the activation of pro-apoptotic cell death protein Bcl2-associated X-protein (Bax). <h3>Background:</h3> ALS is a progressive neurodegenerative disease characterized by motor neuron loss. Its sporadic form is the most prevalent, afflicting 90% of those with ALS. We previously showed that ApoB is a neurotoxic protein increased in sALS patient CSF that induces motor neuron degeneration. Mice injected intrathecally with ApoB exhibit the same motor neuron degeneration as those injected with sALS CSF, and cultured human motor neurons treated with pathogenic concentrations of ApoB undergo cell death. As Bax is a common pro-cell death regulator, we investigate in vitro whether ApoB-induced motor neuron death is Bax-dependent. <h3>Design/Methods:</h3> Human iPSC-derived motor neurons were cultured for 8 days, then incubated for 1 hour with 50 μM, 100 μM, or 200 μM Bax-inhibiting peptide V5 (Calbiochem). Motor neurons were then treated with 0.005 ng/μL ApoB. One day after treatment, cells were fixed for ChAT immunocytochemistry. Area of motor neuron clusters was quantified as a measure of motor neuron survival. <h3>Results:</h3> ApoB in sALS CSF induces human motor neuron death in vitro, as shown by significantly smaller ChAT⁺ clusters than motor neurons grown in media. However, treatment with the Bax-inhibiting peptide resulted in a dose-dependent protection against ApoB-induced motor neuron death. ChAT⁺ cluster size showed a direct positive correlation with Bax inhibitor concentration. <h3>Conclusions:</h3> Our in vitro studies show that ApoB-induced human motor neuron death is mediated by Bax activation, which can be prevented with a Bax inhibitor. This suggests Bax-dependent apoptosis is a likely mechanism of ApoB-induced motor neuron degeneration. Bax inhibitors may have therapeutic value in ALS. <b>Disclosure:</b> Miss Gao has nothing to disclose. Ms. Griffin has nothing to disclose. Dr. Wong has nothing to disclose. Dr. Sadiq has nothing to disclose.

Identification and characterisation of a rare MTTP variant underlying hereditary non-alcoholic fatty liver disease

Background & AimsNon-alcoholic fatty liver disease (NAFLD) is a complex trait with an estimated prevalence of 25% globally. We aimed to identify the genetic variant underlying a four-generation family with progressive NAFLD leading to cirrhosis, decompensation, and development of hepatocellular carcinoma in the absence of common risk factors such as obesity and type 2 diabetes. MethodsExome sequencing and genome comparisons were used to identify the likely causal variant. We extensively characterised the clinical phenotype and post-prandial metabolic responses of family members with the identified novel variant in comparison with healthy non-carriers and wild-type patients with NAFLD. Variant-expressing hepatocyte-like cells (HLCs) were derived from human-induced pluripotent stem cells generated from homozygous donor skin fibroblasts and restored to wild-type using CRISPR-Cas9. The phenotype was assessed using imaging, targeted RNA analysis, and molecular expression arrays. ResultsWe identified a rare causal variant c.1691T>C p.I564T (rs745447480) in MTTP, encoding microsomal triglyceride transfer protein (MTP), associated with progressive NAFLD, unrelated to metabolic syndrome and without characteristic features of abetalipoproteinaemia. HLCs derived from a homozygote donor had significantly lower MTP activity and lower lipoprotein ApoB secretion than wild-type cells, while having similar levels of MTP mRNA and protein. Cytoplasmic triglyceride accumulation in HLCs triggered endoplasmic reticulum stress, secretion of pro-inflammatory mediators, and production of reactive oxygen species. ConclusionsWe have identified and characterised a rare causal variant in MTTP, and homozygosity for MTTP p.I564T is associated with progressive NAFLD without any other manifestations of abetalipoproteinaemia. Our findings provide insights into mechanisms driving progressive NAFLD. Impact and ImplicationsA rare genetic variant in the gene MTTP has been identified as responsible for the development of severe non-alcoholic fatty liver disease in a four-generation family with no typical disease risk factors. A cell line culture created harbouring this variant gene was characterised to understand how this genetic variation leads to a defect in liver cells, which results in accumulation of fat and processes that promote disease. This is now a useful model for studying the disease pathways and to discover new ways to treat common types of fatty liver disease.

A bibliometric analysis and visualization of literature on non-fasting lipid research from 2012 to 2022.

Non-fasting lipid assessment can help predict cardiovascular disease risks and is linked to multiple diseases, particularly diabetes. The significance of non-fasting lipid levels in routine screening and postprandial lipid tests for potential dyslipidemia has not been conclusively determined. Various new lipid-lowering strategies have been developed to improve non-fasting dyslipidemia. Therefore, analysis of scientific outputs over the past decade is essential to reveal trends, hotspots, and frontier areas for future research in this field. The Science Citation Index Expanded in the Web of Science Core Collection database was searched for publications related to non-fasting lipid research from 2012 to 2022. The regional distributions, authors, disciplines, journals, references, and keywords of the studies were analyzed using the bibliometric software VOSviewer and CiteSpace. A total of 4160 articles and reviews that met the inclusion criteria were included in this study. The output trend was established to be stable and the number of citation indices has been persistently increasing. A total of 104 countries/regions, 4668 organizations, and 20782 authors were involved in this research area. In terms of country, the United States had the largest number of publications (979). The University of Copenhagen was the most productive institution, publishing 148 papers. Professor Børge G Nordestgaard has made the most significant contribution to this field. Nutrients was the most productive journal while the American Journal of Clinical Nutrition was the highest co-cited journal. Analysis of co-cited references indicated that lipid-lowering strategies, statin therapy, high-fat meals, insulin resistance, physical exercise, and fructose were hotspots. Analysis of co-cited keywords revealed that apolipoprotein B, especially apolipoprotein B48, is becoming a key research focus. The keywords "gut microbiota" and "meal timing" were the most extensively studied. The causal relationship between non-fasting dyslipidemia and diseases is currently being explored and the standards for non-fasting or postprandial lipid assessment are continuously being updated. Among the hotspots, lipid-lowering strategies are a potential research direction. Apolipoprotein B48, gut microbiota, and chrononutrition are the research frontiers. This initial bibliometric analysis of non-fasting lipids will enable researchers to monitor swift transformations and recognize novel concepts for upcoming research.

Discordance between lipoprotein (a) and LDL-cholesterol levels in cardiovascular risk assessment in apparently healthy subjects

Background and aimsLipoprotein(a) is a recognized independent cardiovascular risk factor and apolipoprotein B (apoB) level better reflects the risk than LDL-cholesterol. Despite this cardiovascular prediction mostly relies on traditional risk factors. We evaluated the association between Lp(a) and lipid biomarkers of cardiovascular risk in relation to age and sex in apparently healthy individuals. Methods and results422 presumably healthy subjects aged 19–84 were included. Lipid profile, Lp(a), apoB and small dense low-density lipoprotein cholesterol (sdLDL-C) were assayed. Subjects were divided at desirable cut-points of apoB and LDL-C. A group with elevated apoB (≥100 mg/dL) at low LDL-C (≤115 mg/dL) was appointed as high-risk and a group with low apoB but elevated LDL-C as low-risk. Significantly elevated triglycerides, TG/HDL-C and sdLDL-C were found in high risk group, but Lp(a) levels were comparable. TG/HDL-C was the best predictor of high risk with a very good diagnostic accuracy (AUC = 0.85), whereas Lp(a) had no discriminatory power. Women aged ≤40 with low LDL-C ≤ 100 mg/dL and elevated Lp(a) ≥ 40 mg/dL had higher levels of apoB and sdLDL-C (p = 0.002; p = 0.07) than those with Lp(a) < 40 mg/dL, which was not observed in men. In young females increase of LDL-C and apoB significantly raised the risk of elevated Lp(a). ConclusionsWomen younger than 40 with low LDL-C may be at increased cardiovascular risk associated with elevated Lp(a) and apolipoprotein B levels. Inclusion of Lp(a) and apoB in the routine lipid testing providing information on an individual level may improve the prediction of cardiovascular risk in primary prevention.

Correlation Between the Estimated and the Measured Serum Apolipoprotein –B100 in Kurd Subjects: A Trend to Establish a New Formula

Apolipoprotein B100 (ApoB100) provides a good assessment of atherogenic lipoproteins (very low, intermediate, and low-density lipoproteins (VLDL, IDL, and LDL)). There is evidence that polymorphism of ApoB100 was observed in many conditions and it links with obesity, diabetes mellitus hypertension, and chronic inflammation, which could be related to the broad field of the atherothrombotic process, and could be one of the leading causes of coronary artery disease (CAD). It can be computed using a formula that makes use of a measurement of non-high-density lipoprotein levels. This study aimed to derive an estimated equation of ApoB100 from the measured ApoB100 levels specific to the healthy subjects of Kurd race/ethnicity in the Kurdistan region of Iraq taking into consideration the gender-based effect and the status of fasting and postprandial effects. A total number of 45 healthy subjects (23 males and 22 females) were enrolled in the study. The following measurements were achieved: anthropometric indices, blood pressure, lipid profile, including ApoB100, and blood sugar. The biochemical measurements were carried out at fasting and postprandial states. Specific equations were derived for calculating the levels of ApoB100. Significant differences in the anthropometric indices, blood pressure, and lipid profile were observed between males and females. The calculated ApoB100 levels were significantly less than the measured ApoB100 levels in both genders and fasting and postprandial states. The estimated equations for ApoB100 for females have differed from that for males at fasting and postprandial states. The levels of ApoB100 can be determined instead of measuring it in the laboratory by using a specific equation for healthy Kurd people. These equations are gender and race/ethnicity based. The established equation of estimated ApoB100 levels in males differed from that in females which is attributed to the cardio-metabolic factors and higher levels of systolic and mean arterial blood pressures among males. Apo B level is a quantitative index of plasma atherogenic lipids in hypertensive patients who presented with dyslipidemia.

Proteomics analysis of serum from thymoma patients

Thymoma is the most common malignant tumor in thymic epithelial tumors (TETS). This study aimed to identify the changes in serum proteomics in patients with thymoma. Proteins were extracted from twenty patients with thymoma serum and nine healthy controls and prepared for mass spectrometry (MS) analysis. Data independent acquisition (DIA) quantitative proteomics technique was used to examine the serum proteome. Differential proteins of abundance changes in the serum were identified. Bioinformatics was used to examine the differential proteins. Functional tagging and enrichment analysis were conducted using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The string database was used to assess the interaction of different proteins. In all, 486 proteins were found in all samples. There were differences in 58 serum proteins between patients and healthy blood donors, 35 up-regulated and 23 down-regulated. These proteins are primarily exocrine and serum membrane proteins involved in controlling immunological responses and antigen binding, according to GO functional annotation. KEGG functional annotation showed that these proteins play a significant role in the complement and coagulation cascade and the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signal pathway. Notably, the KEGG pathway (complement and coagulation cascade) is enriched, and three key activators were up-regulated: von willebrand factor (VWF), coagulation factor v (F5) and vitamin k-dependent protein c (PC). Protein–protein interaction (PPI) analysis showed that six proteins ((VWF, F5, thrombin reactive protein 1 (THBS1), mannose-binding lectin-associated serine protease 2 (MASP2), apolipoprotein B (APOB), and apolipoprotein (a) (LPA)) were up-regulated and two proteins (Metalloproteinase inhibitor 1(TIMP1), ferritin light chain (FTL)) were down-regulated. The results of this study showed that several proteins involved in complement and coagulation cascades were up-regulated in the serum of patients.

Genetic Identification of Homozygous Familial Hypercholesterolemia by Long-Read Sequencing Among Patients With Clinically Diagnosed Heterozygous Familial Hypercholesterolemia.

Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disorder characterized by extremely elevated plasma LDL-C (low-density lipoprotein cholesterol) and accelerated atherosclerosis. Accurate identification of patients with HoFH is essential as they may be eligible for specialized treatments. We hypothesized that a subset of patients with clinically diagnosed heterozygous FH (HeFH) may in fact have HoFH, and this could be identified by genetic diagnosis. We recruited patients with a clinical diagnosis of HeFH based on a Dutch Lipid Clinic Network score ≥6 and no secondary cause of hypercholesterolemia. We performed targeted next-generation sequencing of the LDLR, APOB, PCSK9, and LDLRAP1 genes, followed by long-read sequencing of the LDLR gene in patients with >1 pathogenic LDLR variant. We examined lipid levels and cardiovascular events. Among 705 patients with clinically diagnosed HeFH, we identified a single pathogenic variant in 300 (42.6%) and >1 pathogenic variant in the LDLR gene in 11 patients (1.6%). We established a genetic diagnosis of HoFH in 6 (0.9%) patients (3 true homozygotes and 3 compound heterozygotes). The mean baseline LDL-C and prevalence of premature cardiovascular disease of patients with genetically identified HoFH was significantly higher than patients with HeFH. In a cohort of patients with clinically diagnosed HeFH, genetic testing including long-read sequencing revealed that 0.9% had HoFH. These patients tended to have a more severe clinical phenotype. Genetic testing of patients with clinical FH may identify patients with HoFH that had eluded clinical diagnosis.

The bioactive peptide VLATSGPG regulates the abnormal lipid accumulation and inflammation induced by free fatty acids in HepG2 cells via the PERK signaling pathway

VLATSGPG (VLA) was a DPP-IV inhibitory peptide isolated from salmon (Salmo Salar) skin. Here, we demonstrated that VLA inhibited the activation of PERK through the AKT signaling pathway. Furthermore, we investigated the effect of VLA on free fatty acid (FFA)-induced lipid accumulation disorder and inflammation in HepG2 cells, elucidating the potential regulatory mechanism in this nonalcoholic fatty liver disease cell model. VLA reduced the mRNA expression of adipogenic factors FAS, ACC, and SCD-1 through the PERK/eIF2α pathway and the level of apolipoprotein B-100 secretion. These may contribute to the reducing FFA-induced lipid accumulation in cells and reducing intracellular lipid levels. In addition, VLA increased IκBα mRNA expression via the PERK/IκBα pathway, inhibited the NF-κB p65 activation, and thus inhibited cell inflammation.

Possibilities of lipid clinics in identifying patients with familial hypercholesterolemia

Aim. To assess the detection rate of familial hypercholesterolemia among outpa­tients visiting a lipidologist.Material and methods. We analyzed the causes and nature of lipid metabolism disorders in patients of the Adult Lipidology Center as follows: 1233 people aged 18-84, including 777 women (63,02%) and 456 men (36,98%). Biomaterial samples from 421 patients with the phenotype of definite, possible or probable familial hypercholesterolemia were studied by massive parallel sequencing using a panel of 5 genes associated with familial hypercholesterolemia (LDLR, LDLRAP1, APOB, APOE, PCSK9). For statistical processing, descriptive statistics methods were used.Results. Working-age patients apply 1,56 times more often than patients of the older age group (60,91% vs 39,09%), and the vast majority of them were referred by a primary care physician based on data from periodic health examinations. The mean level of total cholesterol and low-density lipoprotein cholesterol in the lipidology center was 7,58 and 4,8, respectively. Out of 421 samples, 127 patients (10,3% of the total number of patients and 30,16% of the number of biosamples) had previously described variants of the LDLR, APOB and/or PCSK9 genes associated with familial hypercholesterolemia.Conclusion. The detection rate of definite familial hypercholesterolemia ranges from 5,51 to 8,43% of outpatients visiting a lipidologist, while the proportion of verified carriers of gene mutations related to familial hypercholesterolemia is 10,3%. The diagnosis should not be rejected with a formally low probability according to the S. Broom and DLCN criteria, as well as when identifying data suggestive of secondary lipid metabolism disorders.

The association between retinal microvasculature derived from optical coherence tomography angiography and systemic factors in type 2 diabetics.

To investigate the correlation between the retinal microvasculature using optical coherence tomography angiography (OCTA) and systemic factors in type 2 diabetes mellitus (T2DM) patients. This cross-sectional study obtained OCTA data from patients with T2DM administered at hospital and referred to ophthalmic services. Patient data about demographics, comorbid conditions, and blood biomarkers were extracted from electronic medical records. Data from OCTA scans obtained by CIRRUS HD-OCT Model 5,000 were obtained. Vessel density (VD) and perfusion density (PD) within the superficial capillary plexus, and foveal avascular zone (FAZ) area were automatically segmented. These parameters were tested for their correlations with systemic factors by univariate and multivariable linear regression analyses. A total of 144 T2DM patients (236 eyes) were available for analysis, with mean age of 53.6 (SD = 10.34) and 56.9% were male. Chronic kidney disease, cardiovascular disease, increased serum creatinine (Scr), red blood cell count (RBC), platelets (PLT), apolipoprotein B (APOB), and decreased urine albumin to creatinine ratio (UACR) were significantly associated with lower VD and PD (all p < 0.013). UACR and triglyceride (TRIG) were significantly correlated with FAZ area (all p < 0.017). In multivariate analyses, PLT, eGFR, and APOB were independent risk factors for retinal rarefaction, and UACR was a significant predictor of FAZ area. We found several systemic risk factors, such as PLT, renal function and lipid profiles were associated with PD, VD, and FAZ area among Chinese T2DM patients.

New CRISPR Technology for Creating Cell Models of Lipoprotein Assembly and Secretion.

This review is aimed at providing an overview of new developments in gene editing technology, including examples of how this technology has been used to develop cell models for studying the effects of gene ablation or missense mutations on lipoprotein assembly and secretion. CRISPR/Cas9-mediated gene editing is superior to other technologies because of its ease, sensitivity, and low off-target effects. This technology has been used to study the importance of microsomal triglyceride transfer protein in the assembly and secretion of apolipoprotein B-containing lipoproteins, as well as to establish causal effects of APOB gene missense mutations on lipoprotein assembly and secretion. CRISPR/Cas9 technology is anticipated to provide unprecedented flexibility in studying protein structure and function in cells and animals and to yield mechanistic insights into variants in the human genome.