Lipoprotein (a): structure, pathophysiology and clinical implications

Serum Lipoprotein(a) Levels as a Predictor of Aortic Stiffness in Patients on Long-Term Peritoneal Dialysis

BACKGROUND Lipoprotein (a) [Lp(a)] is associated with atherosclerosis and cardiovascular mortality in patients with kidney failure. Aortic stiffness (AS), measured primarily by carotid-femoral pulse wave velocity (cfPWV), reflects vascular aging and precedes end-organ failure. This study aimed to evaluate the association between serum Lp(a) levels and cfPWV in patients undergoing peritoneal dialysis (PD). MATERIAL AND METHODS In this cross-sectional study, which included 148 patients with long-term PD for end-stage kidney failure, cfPWV was measured using a cuff-based method. AS was defined as a cfPWV exceeding 10 m/s, and an enzyme-linked immunosorbent assay was used to determine serum Lp(a) levels. Univariate and multivariate regression analyses were performed to identify the clinical correlates of AS. RESULTS There were 32 (21.6%) patients diagnosed with AS. Based on the multivariate logistic regression analysis, the odds ratio for AS was 1.007 (95% confidence interval, 1.003-1.011; P=0.001) for every 1 mg/L increase in Lp(a) levels. Multivariate linear regression analysis showed that Lp(a) (P<0.001), age (P=0.003), waist circumference (P=0.008), systolic blood pressure (P=0.010), and diabetes mellitus (P<0.001) were positively associated with cfPWV. The area under the receiver operating characteristic curve for Lp(a) in differentiating AS from non-AS was 0.770 (95% confidence interval, 0.694-0.835; P<0.0001). CONCLUSIONS Serum Lp(a) level was independently associated with cfPWV and AS in patients with PD.

Targeting Lipoprotein(a): Can RNA Therapeutics Provide the Next Step in the Prevention of Cardiovascular Disease?

Numerous genetic and epidemiologic studies have demonstrated an association between elevated levels of lipoprotein(a) (Lp[a]) and cardiovascular disease. As a result, lowering Lp(a) levels is widely recognized as a promising strategy for reducing the risk of new-onset coronary heart disease, stroke, and heart failure. Lp(a) consists of a low-density lipoprotein-like particle with covalently linked apolipoprotein A (apo[a]) and apolipoprotein B-100, which explains its pro-thrombotic, pro-inflammatory, and pro-atherogenic properties. Lp(a) serum concentrations are genetically determined by the apo(a) isoform, with shorter isoforms having a higher rate of particle synthesis. To date, there are no approved pharmacological therapies that effectively reduce Lp(a) levels. Promising treatment approaches targeting apo(a) expression include RNA-based drugs such as pelacarsen, olpasiran, SLN360, and lepodisiran, which are currently in clinical trials. In this comprehensive review, we provide a detailed overview of RNA-based therapeutic approaches and discuss the recent advances and challenges of RNA therapeutics specifically designed to reduce Lp(a) levels and thus the risk of cardiovascular disease.

Comparative treatment of Sulfasalazine+Ezetimibe combination and Sulfasalazine in a rat model with induced colitis

Ulcerative colitis is a chronic inflammatory disease with high mortality and morbidity worldwide. It causes inflammation in the lining of the colon, resulting in several symptoms that negatively impact the quality of life. Unfortunately, there is currently no known cure for this condition. Therefore, it is crucial to explore alternative treatment approaches. This research aimed to investigate the anti-inflammatory and antioxidative effects of a combination therapy involving Sulfasalazine+Ezetimibe compared to Sulfasalazine alone in a rat model of ulcerative colitis. Forty adult rats were divided into four groups for this study. The groups consisted of a control group (negative control), an acetic acid group (positive control), an acetic acid+Sulfasalazine (100 mg/kg per day) group, and an acetic acid+Sulfasalazine (50 mg/kg)+Ezetimibe (5 mg/kg) group. Rats were treated for one week, and colitis was induced by administering 2 ml of 4% (v/v) acetic acid inter-rectally. After sacrifice, the colonic tissue homogenate was analyzed for several markers, including proinflammatory cytokines (TNF-α, IL-1β, NF-κB), oxidative stress markers (malondialdehyde, myeloperoxidase), and adhesive molecule markers (E-selectin, ICAM-1). Sulfasalazine and the combination of Sulfasalazine+Ezetimibe significantly reduced the colonic levels of TNF-α, IL-1β, NF-κB, MDA, and E-selectin in the homogenate. However, the combination therapy of Sulfasalazine and Ezetimibe demonstrated a superior effect.

Lipoprotein(a): a Case for Universal Screening in Youth

PURPOSE OF REVIEW

Lipoprotein(a) has emerged as a strong independent risk factor for cardiovascular disease. Targeted screening recommendations for Lp(a) measurement exist for adults and youth known to be at high-risk. However, Lp(a) measurements are not included in universal screening guidelines in the US; hence, most families in the US with high Lp(a) levels who are at risk of future atherosclerotic heart disease, stroke, or aortic stenosis are not recognized. Lp(a) measurement included as part of routine universal lipid screening in youth would identify those children at risk of ASCVD and enable family cascade screening with identification and early intervention for affected family members.

RECENT FINDINGS

Lp(a) levels can be reliably measured in children as young as two years of age. Lp(a) levels are genetically determined. The Lp(a) gene is inherited in a co-dominant fashion. Serum Lp(a) attains adult levels by two years of age and is stable for the lifetime of the individual. Novel therapies that aim to specifically target Lp(a) are in the pipeline, including nucleic acid-based molecules such as antisense oligonucleotides and siRNAs. Inclusion of a single Lp(a) measurement performed as part of routine universal lipid screening in youth (ages 9-11; or at ages 17-21) is feasible and cost effective. Lp(a) screening would identify youth at-risk of ASCVD and enable family cascade screening with identification and early intervention for affected family members.

Calcific aortic valve disease: mechanisms, prevention and treatment

Calcific aortic valve disease (CAVD) is the most common disorder affecting heart valves and is characterized by thickening, fibrosis and mineralization of the aortic valve leaflets. Analyses of surgically explanted aortic valve leaflets have shown that dystrophic mineralization and osteogenic transition of valve interstitial cells co-occur with neovascularization, microhaemorrhage and abnormal production of extracellular matrix. Age and congenital bicuspid aortic valve morphology are important and unalterable risk factors for CAVD, whereas additional risk is conferred by elevated blood pressure and plasma lipoprotein(a) levels and the presence of obesity and diabetes mellitus, which are modifiable factors. Genetic and molecular studies have identified that the NOTCH, WNT-β-catenin and myocardin signalling pathways are involved in the control and commitment of valvular cells to a fibrocalcific lineage. Complex interactions between valve endothelial and interstitial cells and immune cells promote the remodelling of aortic valve leaflets and the development of CAVD. Although no medical therapy is effective for reducing or preventing the progression of CAVD, studies have started to identify actionable targets.

The relationship between lipoprotein(a) and risk of cardiovascular disease: a Mendelian randomization analysis

BACKGROUND

Lipoprotein(a) [Lp(a)] is one of the residual risk factors for cardiovascular disease (CVD) in the setting of optimal low-density lipoprotein cholesterol (LDL-C). The association between Lp(a) and CVD is still in the exploratory phase, with few studies indicating a causal connection between Lp(a) and various CVD.

METHODS

Lp(a) (n = 377,590) was a genome-wide association study (GWAS) based on European populations from Neale Lab. Large GWAS datasets for CVD, including aortic aneurysm(AA) (n = 209,366), atrial fibrillation(AF) (n = 1,030,836), coronary heart disease(CHD) (n = 361,194), secondary hypertension(HBP) (n = 164,147), heart failure(HF) (n = 208,178), ischemic stroke (IS) (n = 218,792), large artery atherosclerosis stroke(ISL) (n = 150, 765), small vessel stroke(ISS) (n = 198,048), lacunar stroke(LIS) (n = 225,419), and pulmonary embolism(PE) (n = 218,413) were also based on European populations. We performed separate univariate two-sample Mendelian randomization (MR) analysis for Lp(a) and CVD as described above. We evaluated this connection mainly using the random-effects inverse variance weighted technique(IVW1) with a 95% confidence interval (CI) for the odds ratio (OR). This was supplemented by MR-Egger, weighted median, maximum likelihood, penalized weighted median, and fixed-effects inverse variance weighted methods. MR-PRESSO offers another means of statistical detection.

RESULTS

Our two-sample MR, which was predominately based on IVW1, revealed a causal relationship between Lp(a) and AA (OR = 1.005, 95%CI: 1.001-1.010, P = 0.009), CHD (OR = 1.003, 95%CI 1.001-1.004, P = 0.010), and ISL (OR = 1.003, 9 5%CI 1.002-1.004, P = 9.50E-11), in addition, there is no causal association with AF, HBP, HF, IS, ISS, LIS, or PE. Similar conclusions were reached by the MR-PRESSO method.

CONCLUSION

This MR study suggested a causal relationship between Lp(a) and CHD, AA, and ISL, but not associated with AF, HF, IS, LIS, ISS, HBP, or PE. Our work further verifies the association between Lp(a) and various CVD, resulting in improved Lp(a) management and a reduction in the prevalence of CVD.

Circulating levels of PCSK9, ANGPTL3 and Lp(a) in stage III breast cancers

Background / synopsis

Cholesterol and lipids play an important role in sustaining tumor growth and metastasis in a large variety of cancers. ANGPTL3 and PCSK9 modify circulating cholesterol levels, thus availability of lipids to peripheral cells. Little is known on the role, if any, of circulating lipid-related factors such as PCSK9, ANGPTL3 and lipoprotein (a) in cancers.

Objective/purpose

To compare circulating levels of PCSK9, ANGPTL3, and Lp(a) in women with stage III breast cancer versus women with premalignant or benign breast lesions.

Methods

Twenty-three plasma samples from women diagnosed with a stage III breast cancer (ductal, lobular or mixed) were matched for age with twenty-three plasma samples from women bearing premalignant (stage 0, n = 9) or benign (n = 14) breast lesions. The lipid profile (Apo B, total cholesterol, HDL cholesterol and triglycerides levels) and Lp(a) were measured on a Roche Modular analytical platform, whereas LDL levels were calculated with the Friedewald formula. ANGPTL3 and PCSK9 plasma levels were quantitated by ELISA. All statistical analyses were performed using SAS software version 9.4.

Results

PCSK9 levels were significantly higher in women with stage III breast cancer compared to age-matched counterparts presenting a benign lesion (95.9 ± 27.1 ng/mL vs. 78.5 ± 19.3 ng/mL, p < 0.05, n = 14). Moreover, PCSK9 levels positively correlated with breast disease severity (benign, stage 0, stage III) (Rho = 0.34, p < 0.05, n = 46). In contrast, ANGPTL3 and Lp(a) plasma levels did not display any association with breast disease status and lipids did not correlate with disease severity.

Conclusion

In this small cohort of 46 women, PCSK9 levels tended to increase with the severity of the breast disease. Given that PCSK9 plays an important role in maintaining cholesterolemia, and a potential role in tumor evasion, present results warrant further investigation into a possible association between PCSK9 levels and breast cancer severity in larger cohorts of women.

A method for lipoprotein (a) Isolation from a small volume of plasma with applications for clinical research

High levels of circulating Lipoprotein (a) [Lp(a)] are an independent risk factor for CVD. One of the major limitations to investigating Lp(a) biology is the need for large volumes of plasma (4–10 mL) for its isolation. We developed an isolation technique requiring only 0.4 mL of plasma yielding an enriched Lp(a) fraction suitable for compositional and functional studies. We collected plasma from patients (n = 9) in EDTA presenting to our Center for Preventive Cardiology for CVD risk management and with circulating Lp(a) > 66 mg/dL. 0.4 mL of plasma was added to 90 µL of potassium bromide (1.33 g/mL) and subjected to our two-step density-gradient ultracentrifugation method. The first step separates VLDL and LDL from the Lp(a) and HDL fractions and the second step further separates VLDL from LDL and Lp(a) from HDL. Lp(a) is then dialyzed for up to 24 h in potassium phosphate buffer. We performed cholesterol gel electrophoresis, immunoblotting and LC-MS/MS proteomics on isolated lipoprotein fractions to confirm fraction enrichment. Functional studies including Lp(a)-dependent induction of macrophage gene expression and cholesterol efflux inhibition were performed on isolated Lp(a) to confirm its preserved bioactivity. Lp(a) yields (264 ± 82.3 µg/mL on average) correlated with Lp(a) plasma concentrations (r² = 0.75; p < 0.01) and represented the relative distribution of circulating apo(a) isoforms. Proteomic analyses confirm lipoprotein fraction separation. Functional integrity was confirmed by the findings that isolated Lp(a) inhibited plasminogen-dependent cholesterol efflux in HEK293T cells expressing ABCA1 and increased expressions of Il1b, Nos2 and Ccl2. We developed a small-volume isolation technique for Lp(a) suited for a range of applications used in biomedical research. The use of this technique circumvents volume-dependent limitations and expands our ability to investigate the mysteries of this deleterious lipoprotein.

The relationship between lipoprotein A and other lipids with prostate cancer risk: A multivariable Mendelian randomisation study

BACKGROUND

Numerous epidemiological studies have investigated the role of blood lipids in prostate cancer (PCa) risk, though findings remain inconclusive to date. The ongoing research has mainly involved observational studies, which are often prone to confounding. This study aimed to identify the relationship between genetically predicted blood lipid concentrations and PCa.

METHODS AND FINDINGS

Data for low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides (TG), apolipoprotein A (apoA) and B (apoB), lipoprotein A (Lp(a)), and PCa were acquired from genome-wide association studies in UK Biobank and the PRACTICAL consortium, respectively. We used a two-sample summary-level Mendelian randomisation (MR) approach with both univariable and multivariable (MVMR) models and utilised a variety of robust methods and sensitivity analyses to assess the possibility of MR assumptions violation. No association was observed between genetically predicted concentrations of HDL, TG, apoA and apoB, and PCa risk. Genetically predicted LDL concentration was positively associated with total PCa in the univariable analysis, but adjustment for HDL, TG, and Lp(a) led to a null association. Genetically predicted concentration of Lp(a) was associated with higher total PCa risk in the univariable (ORweighted median per standard deviation (SD) = 1.091; 95% CI 1.028 to 1.157; P = 0.004) and MVMR analyses after adjustment for the other lipid traits (ORIVW per SD = 1.068; 95% CI 1.005 to 1.134; P = 0.034). Genetically predicted Lp(a) was also associated with advanced (MVMR ORIVW per SD = 1.078; 95% CI 0.999 to 1.163; P = 0.055) and early age onset PCa (MVMR ORIVW per SD = 1.150; 95% CI 1.015,1.303; P = 0.028). Although multiple estimation methods were utilised to minimise the effect of pleiotropy, the presence of any unmeasured pleiotropy cannot be excluded and may limit our findings.

CONCLUSIONS

We observed that genetically predicted Lp(a) concentrations were associated with an increased PCa risk. Future studies are required to understand the underlying biological pathways of this finding, as it may inform PCa prevention through Lp(a)-lowering strategies.

Lipoprotein(a) Where Do We Stand? From the Physiopathology to Innovative Terapy

A number of epidemiologic studies have demonstrated a strong association between increasing lipoprotein a [Lp(a)] and cardiovascular disease. This correlation was demonstrated independent of other known cardiovascular (CV) risk factors. Screening for Lp(a) in the general population is not recommended, although Lp(a) levels are predominantly genetically determined so a single assessment is needed to identify patients at risk. In 2019 ESC/EAS guidelines recommend Lp(a) measurement at least once a lifetime, fo subjects at very high and high CV risk and those with a family history of premature cardiovascular disease, to reclassify patients with borderline risk. As concerning medications, statins play a key role in lipid lowering therapy, but present poor efficacy on Lp(a) levels. Actually, treatment options for elevated serum levels of Lp(a) are very limited. Apheresis is the most effective and well tolerated treatment in patients with high levels of Lp(a). However, promising new therapies, in particular antisense oligonucleotides have showed to be able to significantly reduce Lp(a) in phase II RCT. This review provides an overview of the biology and epidemiology of Lp(a), with a view to future therapies.

Association of Lipoprotein (a) variants with risk of cardiovascular disease: a Mendelian randomization study

Background

There is a well-documented empirical relationship between lipoprotein (a) [Lp(a)] and cardiovascular disease (CVD); however, causal evidence, especially from the Chinese population, is lacking. Therefore, this study aims to estimate the causal association between variants in genes affecting Lp(a) concentrations and CVD in people of Han Chinese ethnicity.

Methods

Two-sample Mendelian randomization analysis was used to assess the causal effect of Lp(a) concentrations on the risk of CVD. Summary statistics for Lp(a) variants were obtained from 1256 individuals in the Cohort Study on Chronic Disease of Communities Natural Population in Beijing, Tianjin and Hebei. Data on associations between single-nucleotide polymorphisms (SNPs) and CVD were obtained from recently published genome-wide association studies.

Results

Thirteen SNPs associated with Lp(a) levels in the Han Chinese population were used as instrumental variables. Genetically elevated Lp(a) was inversely associated with the risk of atrial fibrillation [odds ratio (OR), 0.94; 95% confidence interval (95%CI), 0.901–0.987; P = 0.012)], the risk of arrhythmia (OR, 0.96; 95%CI, 0.941–0.990; P = 0.005), the left ventricular mass index (OR, 0.97; 95%CI, 0.949–1.000; P = 0.048), and the left ventricular internal dimension in diastole (OR, 0.97; 95%CI, 0.950–0.997; P = 0.028) according to the inverse-variance weighted method. No significant association was observed for congestive heart failure (OR, 0.99; 95% CI, 0.950–1.038; P = 0.766), ischemic stroke (OR, 1.01; 95%CI, 0.981–1.046; P = 0.422), and left ventricular internal dimension in systole (OR, 0.98; 95%CI, 0.960–1.009; P = 0.214).

Conclusions

This study provided evidence that genetically elevated Lp(a) was inversely associated with atrial fibrillation, arrhythmia, the left ventricular mass index and the left ventricular internal dimension in diastole, but not with congestive heart failure, ischemic stroke, and the left ventricular internal dimension in systole in the Han Chinese population. Further research is needed to identify the mechanism underlying these results and determine whether genetically elevated Lp(a) increases the risk of coronary heart disease or other CVD subtypes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01482-0.

Lipoprotein(a) in atherosclerosis: from pathophysiology to clinical relevance and treatment options

Lipoprotein(a) (Lp(a)) was discovered more than 50 years ago, and a decade later, it was recognized as a risk factor for coronary artery disease. However, it has gained importance only in the past 10 years, with emergence of drugs that can effectively decrease its levels. Lp(a) is a low-density lipoprotein (LDL) with an added apolipoprotein(a) attached to the apolipoprotein B component via a disulphide bond. Circulating levels of Lp(a) are mainly genetically determined. Lp(a) has many functions, which include proatherosclerotic, prothrombotic and pro-inflammatory roles. Here, we review recent data on the role of Lp(a) in the atherosclerotic process, and treatment options for patients with cardiovascular diseases. Currently 'Proprotein convertase subtilisin/kexin type 9' (PCSK9) inhibitors that act through non-specific reduction of Lp(a) are the only drugs that have shown effectiveness in clinical trials, to provide reductions in cardiovascular morbidity and mortality. The effects of PCSK9 inhibitors are not purely through Lp(a) reduction, but also through LDL cholesterol reduction. Finally, we discuss new drugs on the horizon, and gene-based therapies that affect transcription and translation of apolipoprotein(a) mRNA. Clinical trials in patients with high Lp(a) and low LDL cholesterol might tell us whether Lp(a) lowering per se decreases cardiovascular morbidity and mortality.KEY MESSAGESLipoprotein(a) is an important risk factor in patients with cardiovascular diseases.Lipoprotein(a) has many functions, which include proatherosclerotic, prothrombotic and pro-inflammatory roles.Treatment options to lower lipoprotein(a) levels are currently scarce, but new drugs are on the horizon.

Lessons from dermatology about inflammatory responses in Covid-19

The SARS‐Cov‐2 is a single‐stranded RNA virus composed of 16 non‐structural proteins (NSP 1‐16) with specific roles in the replication of coronaviruses. NSP3 has the property to block host innate immune response and to promote cytokine expression. NSP5 can inhibit interferon (IFN) signalling and NSP16 prevents MAD5 recognition, depressing the innate immunity. Dendritic cells, monocytes, and macrophages are the first cell lineage against viruses' infections. The IFN type I is the danger signal for the human body during this clinical setting. Protective immune responses to viral infection are initiated by innate immune sensors that survey extracellular and intracellular space for foreign nucleic acids. In Covid‐19 the pathogenesis is not yet fully understood, but viral and host factors seem to play a key role. Important points in severe Covid‐19 are characterized by an upregulated innate immune response, hypercoagulopathy state, pulmonary tissue damage, neurological and/or gastrointestinal tract involvement, and fatal outcome in severe cases of macrophage activation syndrome, which produce a ‘cytokine storm’. These systemic conditions share polymorphous cutaneous lesions where innate immune system is involved in the histopathological findings with acute respiratory distress syndrome, hypercoagulability, hyperferritinemia, increased serum levels of D‐dimer, lactic dehydrogenase, reactive‐C‐protein and serum A amyloid. It is described that several polymorphous cutaneous lesions similar to erythema pernio, urticarial rashes, diffuse or disseminated erythema, livedo racemosa, blue toe syndrome, retiform purpura, vesicles lesions, and purpuric exanthema or exanthema with clinical aspects of symmetrical drug‐related intertriginous and flexural exanthema. This review describes the complexity of Covid‐19, its pathophysiological and clinical aspects.

High Lipoprotein(a) Levels as a Predictor of Major Adverse Cardiovascular Events in Hospitalized-Acute Myocardial Infarction Patients

Background

Risk stratification models with incorporation of biochemical markers have received attention recently. In acute myocardial infarction (AMI) one such marker is lipoprotein(a) (Lp(a)). Lp(a) has prothrombotic and proinflammatory properties. High levels of Lp(a) probably contribute to the additional adverse effects in AMI, as it enhances the damaging effect of acute thrombosis. This study aimed to evaluate serum Lp(a) as a predictor of major adverse cardiovascular events (MACE) in hospitalized-acute myocardial infarction patients.

Methods

A prospective cohort study was conducted at Sanglah Hospital, Denpasar, during June–August 2018, among 66 people by consecutive sampling. Samples that met the inclusion and exclusion criteria were examined for serum Lp(a) at the time of admission and the occurrence of MACE during hospitalization was observed. Data regarding serum Lp(a), demography, smoking history, dyslipidemia, hypertension, diabetes mellitus, and MACE were collected. Log rank test and Cox proportional hazards regression were conducted with SPSS version 20 for Windows.

Results

During observation, MACE occurred in 25 (38%) patients, including cardiogenic shock in 7 (10.6%) patients, heart failure in 20 (30.3%) patients, cardiovascular death in 5 (7, 6%) patients, malignant arrhythmias in 5 (7.6%) patients, and postinfarction angina in 5 (7.6%) patients. After the Log rank test, a significant difference in survival was observed (p = 0.001) between groups of high Lp(a) (survival rate of 60.6 hours; 95% CI 43.3–77.9) and low Lp(a) (average survival of 104.3 hours, 95% CI 91.4–117.2). The hazard ratio of high Lp(a) against MACE was 4.63 (p=0.002), and it increased to 4.69 in multivariate analysis with Cox proportional hazards regression test (p=0.003).

Conclusion

The high level of Lp(a) in AMI patients was a risk factor for the occurrence of MACE during hospitalization. Patients with high Lp(a) also had worse survival compared to patients with low Lp(a).

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Is Lipoprotein (a) a Risk Factor for Coronary Artery Ectasia?

Background

The pathophysiology of coronary artery ectasia (CAE) is under investigated and not well understood. Atherosclerosis is considered as the main etiologic factor for CAE in adults where more than 50% of CAE patients have atherosclerosis. Recently, lipoprotein (a) (Lp(a)) has emerged as a powerful risk factor for atherosclerosis and coronary artery disease (CAD). Serum levels of Lp(a) in patients with CAE have not been investigated. We assumed that Lp(a) may play a role in the pathogenesis of CAE. Principally, our study aims to identify whether Lp(a) is an independent risk factor for CAE.

Methods

Our study is a prospective pilot study. Study population was collected prospectively from pool of patients referred for elective cardiac catheterization at Jordan University Hospital (JUH) in the period extending from February 17, 2018 to June 31, 2018. Patients were referred for elective coronary angiography after being interviewed and physically examined by a cardiologist (HA). Patients with known history of CAD or who are already on anti-lipidemic drugs either documented in the medical records or by interviewing patients for history of revascularization were excluded from the study.

Results

Regarding the primary outcome, there was no significant difference in Lp(a) concentrations between normal and ectasia groups in the general sample (median: 17.5mg/dL vs. 20.4 mg/dL, P value = 0.38).

Conclusions

Our study concludes that there is no detected relationship between elevated Lp(a) levels and developing CAE. CAE was more common in patients with low high-density lipoprotein (HDL) level (compared with patients with normal coronaries), higher total cholesterol level (compared with patients with non-obstructive stenosis) and higher hemoglobin A1c (HbA1c).

Lipoprotein(a) the Insurgent: A New Insight into the Structure, Function, Metabolism, Pathogenicity, and Medications Affecting Lipoprotein(a) Molecule

Lipoprotein(a) [Lp(a)], aka “Lp little a”, was discovered in the 1960s in the lab of the Norwegian physician Kåre Berg. Since then, we have greatly improved our knowledge of lipids and cardiovascular disease (CVD). Lp(a) is an enigmatic class of lipoprotein that is exclusively formed in the liver and comprises two main components, a single copy of apolipoprotein (apo) B-100 (apo-B100) tethered to a single copy of a protein denoted as apolipoprotein(a) apo(a). Plasma levels of Lp(a) increase soon after birth to a steady concentration within a few months of life. In adults, Lp(a) levels range widely from <2 to 2500 mg/L. Evidence that elevated Lp(a) levels >300 mg/L contribute to CVD is significant. The improvement of isoform-independent assays, together with the insight from epidemiologic studies, meta-analyses, genome-wide association studies, and Mendelian randomization studies, has established Lp(a) as the single most common independent genetically inherited causal risk factor for CVD. This breakthrough elevated Lp(a) from a biomarker of atherosclerotic risk to a target of therapy. With the emergence of promising second-generation antisense therapy, we hope that we can answer the question of whether Lp(a) is ready for prime-time clinic use. In this review, we present an update on the metabolism, pathophysiology, and current/future medical interventions for high levels of Lp(a).

Molecular, Population, and Clinical Aspects of Lipoprotein(a): A Bridge Too Far?

There is now significant evidence to support an independent causal role for lipoprotein(a) (Lp(a)) as a risk factor for atherosclerotic cardiovascular disease. Plasma Lp(a) concentrations are predominantly determined by genetic factors. However, research into Lp(a) has been hampered by incomplete understanding of its metabolism and proatherogeneic properties and by a lack of suitable animal models. Furthermore, a lack of standardized assays to measure Lp(a) and no universal consensus on optimal plasma levels remain significant obstacles. In addition, there are currently no approved specific therapies that target and lower elevated plasma Lp(a), although there are recent but limited clinical outcome data suggesting benefits of such reduction. Despite this, international guidelines now recognize elevated Lp(a) as a risk enhancing factor for risk reclassification. This review summarises the current literature on Lp(a), including its discovery and recognition as an atherosclerotic cardiovascular disease risk factor, attempts to standardise analytical measurement, interpopulation studies, and emerging therapies for lowering elevated Lp(a) levels.

Apolipoprotein A5 alleviates LPS/D-GalN-induced fulminant liver failure in mice by inhibiting TLR4-mediated NF-κB pathway

BACKGROUND

Fulminant liver failure (FHF) is a serious clinical problem and liver transplantation is the major intervention. But the overall survival rate of FHF is low owing to the donated organ shortage. Apolipoprotein A-V (ApoA5) is a regulator of triglyceride metabolism and has been reported to act as a predictor for remnant liver growth after preoperative portal vein embolization and liver surgery. This study aimed to investigate the therapeutic effect of ApoA5 on lipopolysaccharide/D-galactosamine (LPS/D-GalN)-induced fulminant liver failure in mice.

METHODS

FHF mouse model was established using LPS/D-GalN and ApoA5 plasmid was injected by tail vein prior to LPS/D-GalN treatment. The expressions of ApoA5, toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and nuclear factor kappa B p65 (NF-κBp65) were assessed by real-time PCR and western blotting. Serum alanine aminotransferase (ALT) and tumor necrosis factor-α (TNF-α) levels were measured using automatic biochemical analyzer. Histological assessment and immunohistochemical (IHC) staining were conducted. Survival rate after LPS/D-GalN administration was also determined with Kaplan-Meier curve. Meanwhile, the expression of ApoA5 in injured huh7 cells was tested. Cell apoptosis analysis was performed after huh7 cells were transfected with ApoA5 plasmid and stimulated with LPS.

RESULTS

The expressions of ApoA5 decreased both in injured huh7 cells and FHF mice. ApoA5 overexpression reduced cell death rate using flow cytometry. ApoA5 not only decreased the serum ALT and TNF-α levels but also attenuated hepatic damage in hematoxylin-eosin (HE)-stained liver section. The protein expressions of TLR4, MyD88 and NF-κBp65 were inhibited when ApoA5 overexpressed. But the inhibitory effect would weaken with the increasing concentration of LPS in spite of ApoA5 overexpression. Besides, ApoA5 improved liver injury in a dose-dependent manner and the survival rate in FHF mice increased with increasing concentration of ApoA5.

CONCLUSION

ApoA5 had a protective effect against LPS/D-GalN-induced fulminant liver failure in mice within a certain range by inhibiting TLR4-mediated NF-κB pathway.

Lipoprotein (a): Examination of Cardiovascular Risk in a Pediatric Referral Population

Atherosclerotic cardiovascular disease (CVD), a leading cause of death globally, has origins in childhood. Major risk factors include family history of premature CVD, dyslipidemia, diabetes mellitus, and hypertension. Lipoprotein (a) [Lp(a)], an inherited lipoprotein, is associated with premature CVD, but its impact on cardiovascular health during childhood is less understood. The objective of the study was to examine the relationship between Lp(a), family history of premature CVD, dyslipidemia, and vascular function and structure in a high-risk pediatric population. This is a single-center, cross-sectional study of 257 children referred to a preventive cardiology clinic. The independent variable, Lp(a), separated children into high-Lp(a) [Lp(a) ≥ 30 mg/dL] and normal-Lp(a) groups [Lp(a) < 30 mg/dL]. Dependent variables included family history of premature CVD; dyslipidemia, defined as low-density lipoprotein cholesterol > 130 mg/dL, high-density lipoprotein cholesterol (HDL-C) < 45 mg/dL, triglycerides (TG) > 100 mg/dL; and vascular changes suggesting early atherosclerosis, as measured by carotid-femoral pulse wave velocity (PWV) and carotid artery intima-media thickness (CIMT). Of the 257 children, 110 (42.8%) had high Lp(a) and 147 (57.2%) had normal Lp(a). There was a higher prevalence of African-American children in the high-Lp(a) group (19.3%) compared to the normal-Lp(a) group (2.1%) (p < 0.001). High Lp(a) was associated with positive family history of premature CVD (p = 0.03), higher-than-optimal HDL-C (p = 0.02), and lower TG (p < 0.001). There was no difference in PWV or CIMT between groups. High Lp(a) in children is associated with family history of premature CVD and is prevalent in African-American children. In children with high Lp(a), promotion of intensive lifestyle modifications is prudent to decrease premature CVD-related morbidity.

Genome-wide mapping of plasma protein QTLs identifies putatively causal genes and pathways for cardiovascular disease

Identifying genetic variants associated with circulating protein concentrations (protein quantitative trait loci; pQTLs) and integrating them with variants from genome-wide association studies (GWAS) may illuminate the proteome's causal role in disease and bridge a knowledge gap regarding SNP-disease associations. We provide the results of GWAS of 71 high-value cardiovascular disease proteins in 6861 Framingham Heart Study participants and independent external replication. We report the mapping of over 16,000 pQTL variants and their functional relevance. We provide an integrated plasma protein-QTL database. Thirteen proteins harbor pQTL variants that match coronary disease-risk variants from GWAS or test causal for coronary disease by Mendelian randomization. Eight of these proteins predict new-onset cardiovascular disease events in Framingham participants. We demonstrate that identifying pQTLs, integrating them with GWAS results, employing Mendelian randomization, and prospectively testing protein-trait associations holds potential for elucidating causal genes, proteins, and pathways for cardiovascular disease and may identify targets for its prevention and treatment.

Low LPA gene kringle IV-2 repeat copy number association with elevated lipoprotein (a) concentration as an independent risk factor of coronary atherosclerotic heart disease in the Chinese Han population

Background

Lipoprotein (a) [Lp(a)], which is genetically determined by the LPA gene kringle IV type 2 (KIV-2) repeat copy number, has previously been reported in different populations. However, it is uncertain if the same occurs in the Chinese Han population. This study explored the correlation of Lp(a) mass or particle concentration with KIV-2 repeat copy number and application for coronary atherosclerotic heart disease (CAHD) risk assessment.

Methods

A cross-sectional study including 884 subjects was conducted. The Lp(a) level and routine risk factors of CAHD were compared. The KIV-2 copy number distribution, relationship with Lp(a), and assessment for CAHD risk were explored.

Results

The mean of Lp(a) mass or particle concentration in the CAHD group was higher than that in the non-CAHD group, while the KIV-2 copy number in the CAHD group was lower. Lp(a) had auxiliary values in gauging the type of plaque and was significantly higher in the soft-plaque group than that in the other two groups (200 mg/L [21.5 nmol/L], 166 mg/L [18.6 nmol/L], 149 mg/L [17.1 nmol/L], respectively, P < 0.05). Kappa test indicated divergence for the same individual using two Lp(a) concentrations (kappa value was 0.536 [< 0.75]). Elevated Lp(a) was an independent CAHD risk factor, whatever mass or particle concentration, and large KIV-2 copy number was a protective factor.

Conclusion

Lp(a) level and small KIV-2 copy number are risk factors for CAHD in the Chinese Han population; furthermore, elevated Lp(a) may gauge the type of coronary plaque.

Importance of Endogenous Fibrinolysis in Platelet Thrombus Formation

The processes of thrombosis and coagulation are finely regulated by endogenous fibrinolysis maintaining healthy equilibrium. When the balance is altered in favour of platelet activation and/or coagulation, or if endogenous fibrinolysis becomes less efficient, pathological thrombosis can occur. Arterial thrombosis remains a major cause of morbidity and mortality in the world despite advances in medical therapies. The role endogenous fibrinolysis in the pathogenesis of arterial thrombosis has gained increasing attention in recent years as it presents novel ways to prevent and treat existing diseases. In this review article, we discuss the role of endogenous fibrinolysis in platelet thrombus formation, methods of measurement of fibrinolytic activity, its role in predicting cardiovascular diseases and clinical outcomes and future directions.

Association of Serum Lipids with Hepatic Steatosis, Stage of Liver Fibrosis and Viral Load in Chronic Hepatitis C

INTRODUCTION

Hepatitis C Virus (HCV) relies on host lipids for its life cycle contributing to lipid abnormalities and hepatic steatosis. Disease progression is influenced by viral factors interacting with host immune and metabolic pathways. The significance of serum lipids for Chronic Hepatitis C (CHC) assessment is not clearly established yet.

AIM

Our aim was to investigate serum lipids' association with stage of liver fibrosis, steatosis and genotypes in patients with CHC.

MATERIALS AND METHODS

A total of 112 CHC patients (54 male, 58 female, aged 48.6±13.7 years) were studied - 98 genotype 1 (G1) and 14 genotype 3 (G3). Liver cirrhosis (F4) was diagnosed in 31 cases. Steatosis was present in 75 of all patients on ultrasound. Liver biopsy was done in 65 patients and histology showed steatosis in 28, stages of fibrosis (F1-F3) in 56 and F4 in 9 patients (METAVIR). Laboratory panel included complete blood count, liver tests and serum lipid levels (mmol/l) with Friedewald equation estimations. Indirect noninvasive fibrosis scores FIB-4, Aspartate aminotransferase to Platelet Ratio Index (APRI) and Forns index were calculated. HCV RNA was quantified by RT-PCR. Statistical analysis included Spearman's rho, Mann-Whitney U test, Receiver Operating Characteristic (ROC) curve.

RESULTS

Total Cholesterol (TCh) (p=0.002) and Low-Density Lipoprotein (LDL) (p=0.003) in G1 patients were higher when steatosis was present. TCh (p<0.001), High-Density Lipoprotein (HDL) (p=0.018) and LDL (p=0.003) were lower in G1 F4 compared with F1-F3 patients. Triglyceride (TG) levels correlated with FIB-4 (r=0.364, p=0.029), APRI (r=0.333, p=0.047) and Forns index (r=0.423, p=0.010) in G1 patients without steatosis. TG to LDL ratio (TG/LDL) (p=0.001) was higher in F4 than in F1-F3 patients. TG/LDL ratio predicted the presence of F4 in G1 patients without steatosis by an area under the ROC curve 0.900 (p<0.001). TG/LDL ratio > 0.52 was highly specific for F4 without steatosis. Specificity dropped to 76% when steatosis was present. TG/LDL < 0.32 negatively predicted liver cirrhosis. HCV RNA correlated with TG levels (r=0.330, p=0.009) in G1 patients with steatosis and with histological percent of fatty hepatocytes (r=0.585, p=0.028) in G3 patients.

CONCLUSION

Lipid levels in CHC G1 patients depend on the presence of steatosis and cirrhosis. HCV RNA is associated with TG levels in G1 patients with steatosis, but not in G3 patients. In cirrhotic CHC G1 patients cholesterol is low with relatively increased TG. TG/LDL ratio is a potential marker of liver cirrhosis in CHC G1 patients.

Plasma Apolipoprotein A-V Predicts Long-term Survival in Chronic Hepatitis B Patients with Acute-on-Chronic Liver Failure

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is a life-threatening condition, and the lipid metabolism disorder is common in the development of this disease. This prospective observational study aimed to define the characteristics of plasma apolipoprotein A-V (apoA-V) in long-term outcome prediction of HBV-ACLF, and a total of 330 HBV-ACLF patients were included and followed for more than 12 months. In this cohort, the 4-week, 12-week, 24-week and 48-week cumulative mortality of HBV-ACLF was 18.2%(60/330), 50.9%(168/330), 59.7%(197/330) and 63.3%(209/330), respectively. As compared to survivors, the non-survivors had significantly lower concentrations of plasma apoA-V on admission. Plasma apoA-V concentrations were positively correlated with prothrombin time activity (PTA), and negatively correlated with interleukin-10, tumor necrosis factor-α, and iMELD scores. Though plasma apoA-V, PTA, total bilirubin(TBil) and blood urea nitrogen(BUN) were all independent factors to predict one-year outcomes of HBV-ACLF, plasma apoA-V had the highest prediction accuracy. And its optimal cutoff value for one-year survival prediction was 480.00 ng/mL, which had a positive predictive value of 84.68% and a negative predictive value of 92.23%. In summary, plasma apoA-V decreases significantly in non-survivors of HBV-ACLF, and it may be regarded as a new predictive marker for the prognosis of patients with HBV-ACLF.

Action mechanism and cardiovascular effect of anthocyanins: a systematic review of animal and human studies

Cardiovascular diseases (CVD) are an important cause of death worldwide. Anthocyanins are a subgroup of flavonoids found in berries, flowers, fruits and leaves. In epidemiological and clinical studies, these polyphenols have been associated with improved cardiovascular risk profiles as well as decreased comorbidities. Human intervention studies using berries, vegetables, parts of plants and cereals (either fresh or as juice) or purified anthocyanin-rich extracts have demonstrated significant improvements in low density lipoproteins oxidation, lipid peroxidation, total plasma antioxidant capacity, and dyslipidemia as well as reduced levels of CVD molecular biomarkers. This review discusses the use of anthocyanins in animal models and their applications in human medicine, as dietary supplements or as new potent drugs against cardiovascular disease.

Serum Lipoprotein (a) Levels in Black South African Type 2 Diabetes Mellitus Patients

Lipoprotein (a) (Lp(a)) which is a low-density lipoprotein-like particle containing apo(a) is considered as an emergent cardiovascular risk factor. Type 2 diabetes mellitus (T2DM) is associated with a two- to threefold increase in the risk of cardiovascular disease (CVD). The aim of this study was to investigate the levels of Lp(a) in Black South African T2DM patients and its association with other metabolic factors. 67 T2DM patients and 48 healthy control participants were recruited for the cross-sectional study. The Lp(a) level was determined by ELISA and the result was analyzed using SPSS. The Lp(a) level in diabetics was found to be significantly increased (P = 0.001) when compared to the normal healthy group. In the diabetic group, the Lp(a) levels correlated significantly with the duration of diabetes (P = 0.008) and oxidized LDL (ox-LDL) levels (P = 0.03) and decreased total antioxidant capacity (P = 0.001). The third tertile of Lp(a) was significantly correlated with increased ox-LDL, C-reactive protein, and triglycerides and decreased total antioxidant capacity.

Serum lipid profile spectrum and delayed cerebral ischemia following subarachnoid hemorrhage: Is there a relation?

BACKGROUND

Serum lipid abnormalities are known to be important risk factors for vascular disorders. However, their role in delayed cerebral ischemia (DCI), the major cause of morbidity after subarachnoid hemorrhage (SAH) remains unclear. This study was an attempt to evaluate the spectrum of lipid profile changes in SAH compared to matched controls, and their relation with the occurrence of DCI.

METHODS

Admission serum lipid profile levels were measured in patients of SAH and prospectively studied in relation to various factors and clinical development of DCI.

RESULTS

Serum triglyceride (TG) levels were significantly lower among SAH patients compared to matched controls (mean [±standard deviation (SD)] mg/dL: 117.3 [±50.4] vs. 172.8 [±89.1], P = 0.002), probably because of energy consumption due to hypermetabolic response. Patients who developed DCI had significantly higher TG levels compared to those who did not develop DCI (mean [±SD] mg/dL: 142.1 [±56] vs. 111.9 [±54], P = 0.05). DCI was noted in 62% of patients with TG >150 mg/dL, compared to 22% among the rest (P = 0.01). Total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and lipoprotein (a) neither showed a significant difference between SAH and controls and nor any significant association with DCI. Multivariate analysis using binary logistic regression adjusting for the effects of age, sex, systemic disease, World Federation of Neurosurgical Societies grade, Fisher grade, and clipping/coiling, revealed higher TG levels to have significant independent association with DCI (P = 0.01).

CONCLUSIONS

Higher serum TG levels appear to be significantly associated with DCI while other lipid parameters did not show any significant association. This may be due to their association with remnant cholesterol or free fatty acid-induced lipid peroxidation.