The efficacy and safety of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors combined with statins in patients with hypercholesterolemia: a network meta-analysis.

Background: In recent years, the position of PCSK9 inhibitors as adjuvant therapy to statins in guidelines has further improved. However, there remained a dearth of direct comparative studies among different PCSK9 inhibitors. Therefore, this study aimed to conduct a network meta-analysis to evaluate the efficacy and safety of different PCSK9 inhibitors combined with statins. Methods: A comprehensive literature search was conducted from the study's inception to 12 November 2023, encompassing multiple online databases including PubMed, Embase, Cochrane Central, Web of Science, and ClinicalTrials.gov to obtain relevant randomized controlled trials. Frequentist network meta-analysis was employed to compare the efficacy and safety of different PCSK9 inhibitors. The efficacy endpoints were low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (ApoB), and lipoprotein (a) (Lp(a)). The safety endpoints were any adverse events (AE), severe adverse events (SAE), AE leading to treatment discontinuation, and injection-site reaction. Results: Compared with placebo and ezetimibe, all PCSK9 inhibitors demonstrated significant reductions in LDL-C levels. Notably, evolocumab exhibited the most pronounced effect with a treatment difference of -63.67% (-68.47% to -58.87%) compared with placebo. Regarding dosage selection for evolocumab, the regimen of 140 mg Q2W (-69.13%, -74.55% to -63.72%) was superior to 420 mg QM (-61.51%, -65.97% to -57.05%). Based on rankings and P-scores analysis, tafolecimab 150 mg Q2W demonstrated superior efficacy in reducing ApoB levels (-61.70%, -84.38% to -39.02%) and Lp(a) levels (-43%, 30%, -68%, 81% to -17%, 79%). Furthermore, the safety profile of PCSK9 inhibitors was favorable with no increase in the incidence of AE, SAE, or AE leading to treatment discontinuation; however, alirocumab, inclisiran, and tafolecimab may potentially entail a potential risk associated with injection-site reactions. Conclusion: Compared with placebo and ezetimibe, PCSK9 inhibitors can significantly reduce LDL-C, ApoB, and Lp(a) when combined with statins to treat hypercholesterolemia. Furthermore, PCSK9 inhibitors and ezetimibe exhibit similar safety profiles. Systematic Review Registration: [PROSPERO], identifier [CRD42023490506].

The relationship between early-onset coronary artery disease and familial hypercholesterolemia: a cohort study based on the Hakka population in Meizhou, China.

BACKGROUND: The low diagnosis and treatment rates of familial hypercholesterolemia (FH) have become a global issue. This study aims to explore the correlation between early-onset coronary artery disease (CAD) and FH in the Hakka population in Meizhou, Guangdong. METHODS: Clinical data of Hakka patients with early-onset CAD, admitted to the Meizhou People's Hospital from January 2023 to January 2024 were retrospectively analyzed. The patients were categorized into an FH group and a non-FH group. Biochemical indicators, lipid levels, echocardiographic parameters, clinical phenotypes, and genetic typing of early-onset CAD patients in the Hakka population were analyzed for their correlation with FH. RESULTS: A total of 167 Hakka patients with early-onset CAD were included, among whom 22 patients had FH. The FH group showed lower triglyceride (TG) level [1.785 (1.40, 2.10) vs. 2.090 (1.80, 2.30), P = 0.002] and higher levels of total cholesterol (TC) [6.635 (5.60, 7.10) vs. 4.830 (4.00, 5.40), P<0.001], low-density lipoprotein cholesterol (LDL-C) [4.440 (3.90, 5.20) vs. 2.820 (2.40, 3.30), P<0.001], and apolipoprotein B (Apo B) [1.600 (1.30, 1.80) vs. 0.910 (0.70, 1.10), P<0.001]. FH was correlated with TG, TC, LDL-C and Apo B levels (r1 = -0.235; r2 = 0.441; r3 = 0.483; r4 = 0.538). TG is a risk factor while TC, LDL-C and Apo B are protective factors for FH. CONCLUSION: The incidence of FH is relatively high among early-onset CAD patients in the Hakka population in Meizhou. TG, TC, LDL-C, and Apo B levels are valuable in aiding clinical differential diagnosis of CAD patients with FH.

APOBEC-1 Complementation Factor: From RNA Binding to Cancer.

BACKGROUND: APOBEC-1 complementation factor (A1CF) and Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-1 (APOBEC-1) constitute the minimal proteins necessary for the editing of apolipoprotein B (apoB) mRNA in vitro. Unlike APOBEC-1 and apoB mRNA, the ubiquitous expression of A1CF in human tissues suggests its unique biological significance, with various factors such as protein kinase C, thyroid hormones, and insulin regulating the activity and expression of A1CF. Nevertheless, few studies have provided an overview of this topic. OBJECTIVE: We conducted a literature review to describe the molecular mechanisms of A1CF and its relevance to human diseases. METHOD: In the PubMed database, we used the keywords 'A1CF' and 'APOBEC-1 complementation factor' to collect peer-reviewed articles published in English from 2000 to 2023. Two authors independently reviewed the articles and reached the consensus. RESULT: After reviewing 127 articles, a total of 61 articles that met the inclusion criteria were included in the present review. Studies revealed that A1CF is involved in epigenetic regulation of reproductive cells affecting embryonic development, and that it is closely associated with the occurrence of gout due to its editing properties on apoB. A1CF can also affect the process of epithelial-mesenchymal transition in renal tubular epithelial cells and promote liver regeneration by controlling the stability of IL-6 mRNA, but no influence on cardiac function was found. Furthermore, increasing evidence suggests that A1CF may promote the occurrence and development of breast cancer, lung cancer, renal cell carcinoma, hepatocellular carcinoma, endometrial cancer, and glioma. CONCLUSION: This review clarifies the association between A1CF and other complementary factors and their impact on the development of human diseases, aiming to provide guidance for further research on A1CF, which can help treat human diseases and promote health.

Diagnostic Value of Serum Apolipoprotein B100 Combined With Hippocampal Volume in Alzheimer's Disease.

PURPOSE: To explore the diagnostic value of serum apolipoprotein B100 (Apo B100) combined with hippocampal volume in Alzheimer's disease (AD). METHODS: A total of 59 AD patients and 59 healthy subjects were selected. The Mini-Mental State Examination (MMSE) was used for neuropsychological assessment. Blood glucose and serum lipid levels were detected by biochemical analyzer. Polymerase chain reaction (PCR) was used to detect apolipoprotein E (Apo E) ε3/ε4 genotypes in the plasma. Hippocampal volume was calculated using Slicer software. Independent-sample t test or Mann-Whitney U test were used to compare the levels of various indicators between the two groups. Spearman's correlation analysis was used to analyze the correlation between each level. The receiver operating characteristic curve (ROC) was plotted, and the area under the curve (AUC) was calculated to compare the diagnostic efficacy of individual and combined detection of serum Apo B100 levels and hippocampal volume in AD. RESULTS: Compared with the healthy control group, the levels of serum total cholesterol (TC), low-density lipoprotein (LDL), Apo B100, and plasma Apo E ε3/ε4 were higher in the AD group, and serum high-density lipoprotein (HDL) level was lower in the AD group (both p < 0.05). The hippocampal volume in the AD group was lower than in the control group (p < 0.01). The serum Apo B100 level was negatively correlated with MMSE score (r = -0.646), whereas hippocampal volume was positively correlated with MMSE score (r = 0.630). ROC curve analysis showed that the AUC of the combined serum Apo B100 level and hippocampal volume for AD was higher than that of either alone (AUC = 0.821, p < 0.01). CONCLUSION: Serum Apo B100 level is elevated, and the hippocampal volume is reduced in AD patients. The combined detection of the two has a higher diagnostic efficiency for AD than other alone and has the potential to become an important indicator for the diagnosis of AD in the future.

J-shaped association between apolipoprotein B and CV outcomes in statin-treated patients with chronic coronary syndrome.

INTRODUCTION AND OBJECTIVES: The association between apolipoprotein B (apoB) and residual cardiovascular (CV) risk in patients with chronic coronary syndrome (CCS) remains unclear. We aimed to investigate the association between apoB levels and CV outcomes in statin-treated CCS patients. METHODS: We enrolled 8641 statin-treated CCS patients at Fuwai Hospital. The patients were divided into 5 groups based on to apoB quintiles (Q1 to Q5). The primary endpoint was 3-year CV events, including CV death, nonfatal myocardial infarction, and nonfatal stroke. RESULTS: During a median follow-up of 3.17 years, there were 232 (2.7%) CV events. After multivariable adjustment, a restricted cubic spline illustrated a J-shaped relationship between apoB levels and 3-year CV events, with the risk remaining flat until apoB levels exceeded 0.73g/L, after which the risk increased (nonlinear P <.05). Kaplan-Meier curves showed the lowest CV event rate in the Q3 group (0.68-0.78g/L). Compared with the Q3 group, multivariable Cox regression models revealed that both low (Q1, ≤0.57g/L) and high (Q5, >0.93g/L) apoB levels were associated with an increased risk of major adverse cardiac events (all P <.05). Notably, patients with low apoB levels (Q1) had the highest risk of CV death (HR, 2.44; 95%CI, 1.17-5.08). CONCLUSIONS: Our analysis indicates that both low and high levels of apoB are associated with elevated CV risk, with the risk being particularly pronounced at higher levels (> 0.73g/L).

Lipoprotein(a) and risk-weighted apolipoprotein B: a novel metric for atherogenic risk.

BACKGROUND: Retention of apolipoprotein B (apoB)-containing lipoproteins within the arterial wall plays a major causal role in atherosclerotic cardiovascular disease (ASCVD). There is a single apoB molecule in all apoB-containing lipoproteins. Therefore, quantitation of apoB directly estimates the number of atherogenic particles in plasma. ApoB is the preferred measurement to refine the estimate of ASCVD risk. Low-density lipoprotein (LDL) particles are by far the most abundant apoB-containing particles. In patients with elevated lipoprotein(a) (Lp(a)), apoB may considerably underestimate risk because Mendelian randomization studies have shown that the atherogenicity of Lp(a) is approximately 7-fold greater than that of LDL on a per apoB particle basis. In subjects with increased Lp(a), the association between LDL-cholesterol and incident CHD (coronary heart disease) is increased, but the association between apoB and incident CHD is diminished or even lost. Thus, there is a need to understand the mechanisms of Lp(a), LDL-cholesterol and apoB-related CHD risk and to provide clinicians with a simple practical tool to address these complex and variable relationships. How can we understand a patient's overall lipid-driven atherogenic risk? What proportion of this risk does apoB capture? What proportion of this risk do Lp(a) particles carry? To answer these questions, we created a novel metric of atherogenic risk: risk-weighted apolipoprotein B. METHODS: In nmol/L: Risk-weighted apoB = apoB - Lp(a) + Lp(a) x 7 = apoB + Lp(a) x 6. Proportion of risk captured by apoB = apoB divided by risk-weighted apoB. Proportion of risk carried by Lp(a) = Lp(a) × 7 divided by risk-weighted apoB. RESULTS: Risk-weighted apoB agrees with risk estimation from large epidemiological studies and from several Mendelian randomization studies. CONCLUSIONS: ApoB considerably underestimates risk in individuals with high Lp(a) levels. The association between apoB and incident CHD is diminished or even lost. These phenomena can be overcome and explained by risk-weighted apoB.

Low prevalence of testing for apolipoprotein B and lipoprotein (a) in the real world.

Objective: Apolipoprotein B (ApoB) and lipoprotein (a) (Lp[a]) are predictors of cardiovascular disease (CVD) risk; therefore, current recommendations for CVD risk assessment and management advocate that patients receive testing for ApoB and Lp(a) in addition to the standard lipid panel. However, US guidelines around ApoB and Lp(a) testing have evolved over time and vary slightly by expert committee. The objective of this analysis was to estimate the number of insured individuals in the USA who received any component of a lipid test, or ApoB and/or Lp(a) testing, during 2019. Methods: We conducted a cross-sectional analysis to estimate the prevalence of any component of a lipid test, ApoB, and/or Lp(a) in the USA using four different claim data sources (including Medicaid, Medicare, and commercially insured enrollees). Prevalence estimates were age-, sex-, payor-, and region-standardized to the 2019 US Annual Social and Economic Supplement of the Current Population Survey. We also described the clinical profile of patients who received lipid testing between 2019 and 2021 (cohort analysis) in Optum claims database. Enrollees were grouped into four non-mutually exclusive cohorts based on their completion of any component of the lipid panel, ApoB, Lp(a), or ApoB and Lp(a). Results: In the prevalence cohort, over a third (38 %) of insured adults in the USA underwent testing for any component of a lipid panel in 2019. This proportion was higher for individuals aged ≥65 years compared to younger adults (62% vs 31 %). The proportion of ApoB and Lp(a) testing represented only <1 % of testing for any component of a lipid panel. In the cohort analysis, we found that lipid testing increased with age and comorbidities. Conclusion: These data should be considered by guideline-issuing agencies and organizations to develop education campaigns encouraging more frequent use of tests beyond the standard lipid panel.

Genetic association analyses highlight apolipoprotein B as a determinant of chronic kidney disease in patients with type 2 diabetes.

BACKGROUND: Blood lipid levels were associated with chronic kidney disease (CKD) in patients with type 2 diabetes (T2D), but the genetic basis and causal nature remains unclear. OBJECTIVE: This study aimed to investigate the relationships of lipids and their fractions with CKD in patients with T2D. METHODS: Our prospective analysis involved 8,607 White participants with T2D but no CKD at baseline from the UK Biobank. Five common lipid traits were included as exposures. Weighted genetic risk scores (GRSs) for these lipid traits were developed. The causal associations between lipid traits, as well as lipid fractions, and CKD were explored using linear or nonlinear Mendelian randomization (MR). The 10-year predicted probabilities of CKD were evaluated via integrating MR and Cox models. RESUTLS: Higher GRS of apolipoprotein B (ApoB) was associated with an increased CKD risk (HR[95 % CI]:1.07[1.02,1.13] per SD;P = 0.008) after adjusting for potential confounders. Linear MR indicated a positive association between genetically predicted ApoB levels and CKD (HR[95 % CI]:1.53[1.12,2.09];P = 0.008), but no evidence of associations was found between other lipid traits and CKD in T2D. Regarding 12 ApoB-contained lipid fractions, a significant causal association was found between medium very-low-density lipoprotein particles and CKD (HR[95 % CI]:1.16[1.02,1.32];P = 0.020). Nonlinear MR did not support nonlinearity in these causal associations. The 10-year probability curve showed that ApoB levels was positively associated with the risk of CKD in patients with T2D. CONCLUSION: Lower ApoB levels were causally associated with a reduced risk of CKD in patients with T2D, positioning ApoB as a potential therapeutic target for CKD prevention in this population.

Role of apolipoprotein B in the clinical management of cardiovascular risk in adults: An expert clinical consensus from the national lipid association.

This National Lipid Association (NLA) Expert Clinical Consensus provides an overview of the physiologic and clinical considerations regarding the role of apolipoprotein B (apoB) measurement to guide clinical care based on the available scientific evidence and expert opinion. ApoB represents the total concentration of atherogenic lipoprotein particles in the circulation and more accurately reflects the atherogenic burden of lipoproteins when compared to low-density lipoprotein cholesterol (LDL-C). ApoB is a validated clinical measurement that augments the information found in a standard lipoprotein lipid panel; therefore, there is clinical value in using apoB in conjunction with a standard lipoprotein lipid profile when assessing risk and managing lipid-lowering therapy (LLT). ApoB has been shown to be superior to LDL-C in risk assessment both before and during treatment with LLT. In individuals, there can be discordance between levels of LDL-C and apoB, as well as LDL-C and non-high-density lipoprotein cholesterol (non-HDL-C), despite high levels of population-wide correlation. When there is discordance between LDL-C and apoB, or LDL-C and non-HDL-C, atherosclerotic cardiovascular disease risk generally aligns better with apoB or non-HDL-C. Additionally, apoB can be used in tandem with standard lipoprotein lipid measurements to diagnose distinct lipoprotein phenotypes. ApoB testing can inform clinical prognosis and care, as well as enable family cascade screening, when an inherited lipoprotein syndrome is identified. The NLA and other organizations will continue to educate clinicians about the role of apoB measurement in improving clinical risk assessment and dyslipidemia management. An urgent need exists to improve access and reimbursement for apoB testing.

Association between 35 blood and urine biomarkers and oral leukoplakia: a two-sample Mendelian randomization study.

Background: Several existing studies have shown a correlation between some of the blood and urine biomarkers and oral leukoplakia (OLK). However, the causality of this relationship remains uncertain. Thus, this study aimed to examine the causal association between 35 blood and urine biomarkers and OLK. Methods: Single nucleotide polymorphisms (SNPs) associated with 35 blood and urine biomarkers were selected as instrumental variables (IVs) using a two-sample Mendelian randomization(MR) study to assess the causal relationship between the biomarkers and the risk of oral leukoplakia. We used the inverse variance weighted (IVW) method as the main analysis. Furthermore, several sensitivity analyses were performed to assess heterogeneity, horizontal pleiotropy, and stability. Results: Based on the selection criteria of the Inverse Variance Weighted (IVW) method, the analysis found that 5 blood and urine biomarkers were significantly associated with the development of leukoplakia, of which the results of IVW showed that abnormalities of Apolipoprotein B (Apo B), Cholesterol, Low-density Lipoprotein (LDL), Triglycerides (TG) promoted the development of oral leukoplakia, and Non Albumin Protein (NAP) had a protective effect on the development of oral leukoplakia. We then performed a Bonferroni correction for these results, and after correction Apo B was still causally associated with the development of oral leukoplakia (IVW P<0.0007), whereas the other four biomarkers could only provide some evidence of predisposition. Conclusion: Our two-sample Mendelian randomization study supports the existence of a causal relationship between these five blood and urine biomarkers and the occurrence of oral leukoplakia, and provides evidence for a number of risk and protective factors for the development of oral leukoplakia; however, the definitive mechanisms for the occurrence and development of oral leukoplakia still remain to be elucidated, and further studies on these relevant mechanisms are still needed.

6-methylcoumarin/miR-122 suppresses hepatic Sortilin-mediated ApoB-100 secretion to attenuate aortic atherosclerosis.

This study aimed to investigate the effects of hepatic microRNA-122 (miR-122) on Sortilin-mediated apolipoprotein B100 (apoB-100) secretion, and on aortic lipid deposition and atherosclerosis (AS) lesions and to clarify the antiatherosclerotic mechanism of 6-methylcoumarin (6-MC) via the modulation of miR-122. Bioinformatics analysis revealed that miR-122 was putatively overexpressed in a liver-specific manner and was downregulated in steatotic livers. miR-122 was shown to suppress the expression of Sortilin by complementarily pairing to the 3'-untranslated region (3'-UTR) of Sortilin mRNA via bioinformatics and dual-luciferase reporter assays, impeding Sortilin-mediated apoB-100 secretion from HepG2 cells. Administration of 6-MC significantly upregulated hepatocellular miR-122 levels, reducing Sortilin expression and apoB-100 secretion in HepG2 cells. The miR-122 mimic vigorously enhanced 6-MC-depressed Sortilin expression, while miR-122 inhibitor repealed the inhibitory effect of 6-MC on Sortilin expression to some extent in HepG2 cells. After internal intervention with the miR-122 precursor, and 6-MC supplementation alone or in combination with the miR-122 sponge led to the reduction in blood triglyceride (TG) levels, low-density lipoprotein-cholesterol (LDL-C) and apoB-100 and a reduction in aortic lipid deposition and AS lesions in apolipoprotein E-deficient (ApoE-/-) mice fed a high fat diet (HFD). The hepatic levels of Sortilin and apoB-100 expression were also decreased in these treated mice. In conclusion, miR-122 suppresses Sortilin expression and Sortilin-mediated apoB-100 secretion to resist circulating LDL production and aortic AS development, which is enhanced by 6-MC-upregulated miR-122 in the liver.

Liver-specific Coxsackievirus and adenovirus receptor deletion develop metabolic dysfunction-associated fatty liver disease.

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a common liver disease associated with obesity and is caused by the accumulation of ectopic fat without alcohol consumption. Coxsackievirus and adenovirus receptor (CAR) are vital for cardiac myocyte-intercalated discs and endothelial cell-to-cell tight junctions. CAR has also been reported to be associated with obesity and high blood pressure. However, its function in the liver is still not well understood. The liver of obese mice exhibit elevated CAR mRNA and protein levels. Furthermore, in the liver of patients with non-alcoholic steatohepatitis, CAR is reduced in hepatocyte cell-cell junctions compared to normal levels. We generated liver-specific CAR knockout (KO) mice to investigate the role of CAR in the liver. Body and liver weights were not different between wild-type (WT) and KO mice fed a paired or high-fat diet (HFD). However, HFD induced significant liver damage and lipid accumulation in CAR KO mice compared with WT mice. Additionally, inflammatory cytokines transcription, hepatic permeability, and macrophage recruitment considerably increased in CAR KO mice. We identified a new interaction partner of CAR using a protein pull-down assay and mass spectrometry. Apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3C (APOBEC3C) demonstrated a complex relationship with CAR, and hepatic CAR expression tightly regulated its level. Moreover, Apolipoprotein B (ApoB) and Low-density lipoprotein receptor (LDLR) levels correlated with APOBEC3C expression in the liver of CAR KO mice, suggesting that CAR may regulate lipid accumulation by controlling APOBEC3C activity. In this study, we showed that hepatic CAR deficiency increased cell-to-cell permeability. In addition, CAR deletion significantly increased hepatic lipid accumulation by inducing ApoB and LDLR expression. Although the underlying mechanism is unclear, CARs may be a target for the development of novel therapies for MAFLD.

Fibrinogen and plasma clot properties are associated with apolipoprotein B and apolipoprotein B-containing lipoproteins in Africans.

BACKGROUND: Case-control, intervention and laboratory studies have demonstrated a link between apolipoprotein B-containing lipoproteins and clot structure and thrombosis. There is, however, limited evidence on population level. OBJECTIVES: We determined the cross-sectional relationship between lipoprotein(a) (Lp(a)), low-density lipoprotein cholesterol (LDL-C), and apolipoprotein B (ApoB) with fibrinogen and plasma clot properties in 1 462 Black South Africans, a population with higher fibrinogen and Lp(a) levels compared with individuals of European descent. METHODS: Data were obtained from participants in the South African arm of the Prospective Urban and Rural Epidemiology study. Clot properties analysed included lag time, slope, maximum absorbance, and clot lysis time (turbidity). Lp(a) was measured in nM using particle-enhanced immunoturbidimetry. General linear models (GLM) were used to determine the associations between ApoB and ApoB-containing lipoproteins with fibrinogen and plasma clot properties. Stepwise regression was used to determine contributors to clot properties and Lp(a) variance. RESULTS: GLM and regression results combined, indicated fibrinogen concentration and rate of clot formation (slope) had the strongest association with Lp(a); clot density associated positively with both Lp(a) and LDL-C; time to clot formation associated negatively with ApoB; and CLT demonstrated strong positive associations with both ApoB and LDL-C, while its association with Lp(a) was fibrinogen concentration dependent. CONCLUSION: These findings suggest that ApoB and the lipoproteins carrying it contribute to prothrombotic clot properties in Africans on epidemiological level and highlight potential novel prothrombotic roles for these (apo)lipoproteins to be considered for the development of targeted therapeutic approaches to address thrombotic conditions related to clot properties.

It is time to address the contribution of cholesterol in all apoB-containing lipoproteins to atherosclerotic cardiovascular disease.

On average, LDL particles are the most populous lipoprotein in serum under fasting conditions. For many reasons, it has been the primary target of lipid-lowering guidelines around the world. In the past 30 years, we have witnessed remarkable changes in each iteration of dyslipidaemia guidelines, with LDL-cholesterol (LDL-C) targets becoming lower and lower among patients at high and very high risk for atherosclerotic cardiovascular disease (ASCVD). The world over, goal attainment rates are low, and hence, ASCVD prevalence remains unacceptably high. Inadequate LDL-C lowering is a major issue in contemporary cardiovascular (CV) medicine. Another issue that vexes even the most astute clinician is that of 'residual risk', meaning the excess risk that remains even after LDL-C is appropriately reduced. In recent years, an important new component of residual risk has emerged: triglyceride-enriched lipoproteins or remnant lipoproteins. These precursors to LDL particles can assume outsized importance among patients with derangements in triglyceride metabolism (e.g. genetic variants, insulin resistance, and diabetes mellitus) and may be more atherogenic than LDL species. Consequently, to reduce total risk for acute CV events, the time has come to include the entire spectrum of apoB-containing lipoproteins in approaches to both risk evaluation and treatment.

Identification of Major Histocompatibility Complex Class II Epitopes From Lyme Autoantigen Apolipoprotein B-100 and Borrelia burgdorferi Mcp4 in Murine Lyme Arthritis.

BACKGROUND: During infection with the Lyme arthritis (LA) pathogen Borrelia burgdorferi, T-cell responses to both host and pathogen are dysregulated, resulting in chronic infection and frequent development of autoimmunity. METHODS: To assess CD4+ T-cell epitopes presented during development of LA, we used an unbiased, immunopeptidomics approach to characterize the major histocompatibility complex (MHC) class II immunopeptidome in B burgdorferi-infected C57BL/6 (B6) mice, which develop mild, self-limiting LA, and infected B6 Il10-/- mice, which develop severe, persistent LA at 0, 4, and 16 weeks postinfection (22-23 mice per group). RESULTS: Peptides derived from proteins involved in adaptive T- and B-cell responses and cholesterol metabolism, including human Lyme autoantigen apolipoprotein B-100 (apoB-100), were enriched in infected Il10-/- mice; whereas peptides derived from proteins involved in neutrophil extracellular net formation were enriched in infected B6 mice. Presentation of apoB-100 peptides showed evidence of epitope expansion during infection. Of several identified B burgdorferi peptides, only 1, a methyl-accepting chemotaxis protein peptide Mcp4442-462, was immunogenic. CONCLUSIONS: ApoB-100, a human Lyme autoantigen, undergoes marked epitope expansion during LA development. The paucity of immunogenic B burgdorferi epitopes supports previous findings suggesting CD4+ T-cell responses are suppressed in murine LA.

Correlation of Apo B/A1 ratio with hemodynamics and hearing impairment degree in elderly patients with sudden sensorineural hearing loss.

Objective: To investigate the correlation of apolipoprotein B/A1 (Apo B/A1) ratio with hemodynamics and degree of hearing impairment in elderly patients with sudden sensorineural hearing loss (SSNHL). Methods: A total of 82 elderly patients with SSNHL diagnosed and treated in our hospital from July 2019 to September 2022 were retrospectively selected as the research group. The patients were divided into the mild group (22 cases), the moderate group (45 cases), and the severe group (15 cases) according to the degree of hearing impairment. 82 elderly people who underwent physical examination in our hospital during the same period were selected as the control group. The ApoB/A1 ratio and hemodynamic [whole blood low-shear viscosity (LSV), whole blood high-shear viscosity (HSV) and plasma viscosity (PV)] were measured in the two groups. The correlation of ApoB/A1 ratio with hemodynamics and degree of hearing impairment was analyzed. The predictive value of ApoB/A1 ratio and hemodynamics for the severity of SSNHL in elderly patients was analyzed. Results: Compared with the control group, the ApoB/A1 ratio, and the levels of LSV, HSV and PV were higher in the research group (P < 0.001). The ApoB/A1 ratio and content of LSV, HSV and PV in the moderate group were significantly increased compared with these in the mild group (P < 0.05). Compared with the moderate group, the ApoB/A1 ratio and the levels of LSV, HSV and PV in the severe group were significantly increased (P < 0.05). Pearson correlation analysis showed that ApoB/A1 was positively correlated with LSV, HSV and PV (r = 0.303, 0.312, 0.228, P < 0.01). Logistic regression analysis showed that the ApoB/A1 ratio, LSV, HSV and PV levels were independent risk factors for the degree of hearing impairment in elderly patients with SSNHL (P < 0.05). The area under the curve (AUC) of ApoB/A1, LSV, HSV and PV for predicting the severity of SSNHL in elderly patients was 0.701, 0.817, 0.838, and 0.765, respectively. The AUC of combined prediction was 0.926, the sensitivity was 86.67 %, and the specificity was 90.06 %. The sensitivity and specificity of combined detection were higher than those of single detection. Conclusion: The contents of ApoB/A1, HSV, LSV and PV were significantly increased in elderly patients with SSNHL, and their levels are significantly related to the degree of hearing impairment. The combined detection has high value in evaluating the severity of the disease.

Evaluation of biochemical algorithms to screen dysbetalipoproteinemia in ε2ε2 and rare APOE variants carriers.

OBJECTIVES: Dysbetalipoproteinemia (DBL) is a combined dyslipidemia associated with an increased risk of atherosclerotic cardiovascular diseases mostly occurring in ε2ε2 subjects and infrequently in subjects with rare APOE variants. Several algorithms have been proposed to screen DBL. In this work, we compared the diagnostic performances of nine algorithms including a new one. METHODS: Patients were divided into 3 groups according to their APOE genotype: ε2ε2 ("ε2ε2", n=49), carriers of rare variants ("APOEmut", n=20) and non-carriers of ε2ε2 nor APOE rare variant ("controls", n=115). The algorithms compared were those from Fredrickson, Sniderman, Boot, Paquette, De Graaf, Sampson, eSampson, Bea and ours, the "Hospices Civils de Lyon (HCL) algorithm". Our gold standard was the presence of a ε2ε2 genotype or of a rare variant associated with triglycerides (TG) >1.7 mmol/L. A replication in the UK Biobank and a robustness analysis were performed by considering only subjects with both TG and low-density lipoprotein-cholesterol (LDLc) >90th percentile. RESULTS: Total cholesterol (TC)/ApoB and NHDLC/ApoB are the best ratios to suspect DBL. In ε2ε2, according to their likelihood ratios (LR), the most clinically efficient algorithms were the HCL, Sniderman and De Graaf's. In APOEmut, Sniderman's algorithm exhibited the lowest negative LR (0.07) whereas the HCL's exhibited the highest positive LR (29). In both cohorts, the HCL algorithm had the best LR. CONCLUSIONS: We proposed a powerful algorithm based on ApoB concentration and the routine lipid profile, which performs remarkably well in detecting ε2ε2 or APOE variant-related DBL. Additional studies are needed to further evaluate algorithms performances in DBL carriers of infrequent APOE variants.

Inhibition of Uracil DNA Glycosylase Alters Frequency and Spectrum of Action-at-a-Distance Mutations Induced by 8-Oxo-7,8-dihydroguanine.

The generation of DNA damage causes mutations and consequently cancer. Reactive oxygen species are important sources of DNA damage and some mutation signatures found in human cancers. 8-Oxo-7,8-dihydroguanine (GO, 8-hydroxyguanine) is one of the most abundant oxidized bases and induces a G→T transversion mutation at the modified site. The damaged G base also causes untargeted base substitution mutations at the G bases of 5'-GpA-3' dinucleotides (action-at-a-distance mutations) in human cells, and the cytosine deaminase apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3 (APOBEC3) is involved in the mutation process. The deaminated cytosine, i.e., uracil, bases are expected to be removed by uracil DNA glycosylase. Most of the substitution mutations at the G bases of 5'-GpA-3' might be caused by abasic sites formed by the glycosylase. In this study, we expressed the uracil DNA glycosylase inhibitor from Bacillus subtilis bacteriophage PBS2 in human U2OS cells and examined the effects on the GO-induced action-at-a-distance mutations. The inhibition of uracil DNA glycosylase increased the mutation frequency, and in particular, the frequency of G→A transitions. These results indicated that uracil DNA glycosylase, in addition to APOBEC3, is involved in the untargeted mutation process induced by GO.