Increased FH-Risk-Score and Diabetes Are Cardiovascular Risk Equivalents in Heterozygous Familial Hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH) is a genetic condition causing premature atherosclerotic cardiovascular disease (ASCVD). It is well established that patients with FH should be treated with statin therapy. However, there exists discordance concerning low-density lipoprotein cholesterol-lowering goals in the management of these patients between different guidelines worldwide. The objective was to compare the 10-year ASCVD risk of different subgroups of patients with and without FH including those with diabetes or a history of ASCVD and patients with FH within different FH-Risk-Score categories. METHODS: This multinational observational study used data from 3 different prospective cohorts. A total of 3383 FH and 6917 non-FH controls matched for age and sex were included (104 363 person-years of follow-up). The 10-year incident ASCVD risk was assessed using Kaplan-Meier estimates, whereas the relative risk was estimated using Cox proportional hazards regression models. RESULTS: FH patients with a high (score >20%) FH-Risk-Score (hazard ratio, 8.45 [95% CI, 6.69-10.67]; P<0.0001), FH patients with diabetes (hazard ratio, 7.67 [95% CI, 4.82-12.21]; P<0.0001), and non-FH patients with ASCVD (hazard ratio, 6.78 [95% CI, 5.45-8.42]; P<0.0001) had a significantly higher incident ASCVD risk over 10 years than the reference group (non-FH without ASCVD or diabetes). The observed 10-year risks in these groups were 32.1%, 30.8%, 30.0%, and 5.1%, respectively. The 10-year ASCVD risk associated with both FH and ASCVD was extremely high (observed risk of 50.7%; hazard ratio, 14.53 [95% CI, 12.14-17.38]; P<0.0001). CONCLUSIONS: This study strongly suggests that the observed risk of FH patients with diabetes, history of ASCVD, and FH-Risk-Score >20% is as high or higher than non-FH individuals with a history of ASCVD. More aggressive management should be recommended for these patients.

Influence of Polygenic Background on the Clinical Presentation of Familial Hypercholesterolemia.

BACKGROUND: Heterozygous familial hypercholesterolemia (FH) is among the most common genetic conditions worldwide that affects ≈ 1 in 300 individuals. FH is characterized by increased levels of low-density lipoprotein cholesterol (LDL-C) and increased risk of coronary artery disease (CAD), but there is a wide spectrum of severity within the FH population. This variability in expression is incompletely explained by known risk factors. We hypothesized that genome-wide genetic influences, as represented by polygenic risk scores (PRSs) for cardiometabolic traits, would influence the phenotypic severity of FH. METHODS: We studied individuals with clinically diagnosed FH (n=1123) from the FH Canada National Registry, as well as individuals with genetically identified FH from the UK Biobank (n=723). For all individuals, we used genome-wide gene array data to calculate PRSs for CAD, LDL-C, lipoprotein(a), and other cardiometabolic traits. We compared the distribution of PRSs in individuals with clinically diagnosed FH, genetically diagnosed FH, and non-FH controls and examined the association of the PRSs with the risk of atherosclerotic cardiovascular disease. RESULTS: Individuals with clinically diagnosed FH had higher levels of LDL-C, and the incidence of atherosclerotic cardiovascular disease was higher in individuals with clinically diagnosed compared with genetically identified FH. Individuals with clinically diagnosed FH displayed enrichment for higher PRSs for CAD, LDL-C, and lipoprotein(a) but not for other cardiometabolic risk factors. The CAD PRS was associated with a risk of atherosclerotic cardiovascular disease among individuals with an FH-causing genetic variant. CONCLUSIONS: Genetic background, as expressed by genome-wide PRSs for CAD, LDL-C, and lipoprotein(a), influences the phenotypic severity of FH, expanding our understanding of the determinants that contribute to the variable expressivity of FH. A PRS for CAD may aid in risk prediction among individuals with FH.

Meta-Analysis of Randomized Trials: Efficacy and Safety of Colchicine for Secondary Prevention of Cardiovascular Disease.

Background: Colchicine has shown potential cardioprotective effects owing to its broad anti-inflammatory properties. We performed a meta-analysis to assess its safety and efficacy in secondary prevention in patients with established coronary artery disease (CAD). Methods: We searched Ovid Healthstar, MEDLINE, and Embase (inception to May 2022) for randomized controlled trials (RCTs) evaluating the cardiovascular effects of colchicine compared with placebo or usual care in patients with CAD. Study-level data on efficacy and safety outcomes were pooled using the Peto method. The primary outcome was the composite of cardiovascular (CV) death, myocardial infarction (MI), or stroke. Results: A total of 8 RCTs were included with a follow-up duration of ≥1 month, comprising a total of 12,151 patients. Compared with placebo or usual care, colchicine was associated with a significant risk reduction in the primary outcome (odds ratio (OR) 0.70, 95% CI 0.60 to 0.83, P < 0.0001; I2 = 52%). Risks of MI (OR 0.75, 95% CI 0.62 to 0.91, P = 0.003; I2 = 33%), stroke (OR 0.47, 95% CI 0.30 to 0.74, P = 0.001; I2 = 0%), and unplanned coronary revascularization (OR 0.67, 95% CI 0.55 to 0.82, P = 0.0001; I2 = 58%) were all reduced in the colchicine group. Rates of CV and all-cause mortality did not differ between the two groups, but there was an increase in noncardiac deaths with colchicine (OR 1.54, 95% CI 1.10 to 2.15, P = 0.01; I2 = 51%). The occurrence of all other adverse events was similar between the two groups, including GI reactions (OR 1.06, 95% CI 0.94 to 1.20, P = 0.35; I2 = 42%) and infections (OR 1.04, 95% CI 0.84 to 1.28, P = 0.74; I2 = 53%). Conclusions: Colchicine therapy may reduce the risk of future cardiovascular events in patients with established CAD; however, there remains a concern about non-CV mortality. Further trials are underway that will shed light on non-CV mortality and colchicine NCT03048825, and NCT02898610.

Docetaxel as a Model Compound to Promote HDL (High-Density Lipoprotein) Biogenesis and Reduce Atherosclerosis.

The recent identification of the cell-surface protein DSC1 (desmocollin 1) as a negative regulator of HDL (high-density lipoprotein) biogenesis has attracted us to revisit the old HDL biogenesis hypothesis: HDL biogenesis reduces atherosclerosis. The location and function of DSC1 suggest that DSC1 is a druggable target for the promotion of HDL biogenesis, and the discovery of docetaxel as a potent inhibitor of the DSC1 sequestration of apolipoprotein A-I has provided us with new opportunities to test this hypothesis. The FDA-approved chemotherapy drug docetaxel promotes HDL biogenesis at low-nanomolar concentrations that are far lower than used in chemotherapy. Docetaxel has also been shown to inhibit atherogenic proliferation of vascular smooth muscle cells. In accordance with these atheroprotective effects of docetaxel, animal studies have shown that docetaxel reduces dyslipidemia-induced atherosclerosis. In the absence of HDL-directed therapies for atherosclerosis, DSC1 constitutes an important new target for the promotion of HDL biogenesis, and the DSC1-targeting compound docetaxel serves as a model compound to prove the hypothesis. In this brief review, we discuss opportunities, challenges, and future directions for using docetaxel in the prevention and treatment of atherosclerosis.

Aortic stenosis in homozygous familial hypercholesterolaemia: a paradigm shift over a century.

AIMS: Homozygous familial hypercholesterolaemia (HoFH) is an orphan disease defined by extreme elevations in low-density lipoprotein cholesterol, cutaneous xanthomas, and pre-mature atherosclerotic cardiovascular disease. Survival has more than doubled over the past three decades. Aortic stenosis (AS) [supravalvular aortic stenosis (SVAS) or valvular aortic stenosis (VAS)] is commonly encountered. There are no medical treatments available and complex high-risk surgeries represent the only available option in severe cases. A systematic review was performed to summarize the current evidence on AS in HoFH and to determine whether pharmacological treatment (statins) have had an impact on clinical presentation, phenotype and clinical course over the past nine decades (PROSPERO CRD42021250565). METHODS AND RESULTS: MEDLINE, Embase Classic + Embase, Cochrane Central Register of Controlled Trials, PubMed, AfricaWide, and Scopus were searched from inception to 10 November 2021. Searches identified 381 publications, of which 19 were retained; they were cross-sectional or retrospective studies. Separately, 108 individual case reports were described. Within the 424 HoFH cases, AS was identified in 57% of patients in the pre-statin era vs. 35% in patients reported more recently (>2000, long-term statin period). With an increase in longevity due to statins and lipoprotein apheresis, a change in the proportion of patients with SVAS and VAS with a SVAS:VAS ratio of 47:53 and 10:90 for HoFH patients not on statin and on long-term statin, respectively, was noted. CONCLUSION: These data suggest that SVAS and VAS are frequent in HoFH and that the phenotype has shifted towards calcific VAS as statins and lipoprotein apheresis improve survival in these patients.

Familial Hypercholesterolemia-Risk-Score: A New Score Predicting Cardiovascular Events and Cardiovascular Mortality in Familial Hypercholesterolemia.

Objective: Familial hypercholesterolemia (FH) is associated with a high risk of premature atherosclerotic cardiovascular disease (ASCVD). However, this risk is highly heterogeneous and current risk prediction algorithms for FH suffer from limitations. The primary objective of this study was to develop a score predicting incident ASCVD events over 10 years in a large multinational FH cohort. The secondary objective was to investigate the prediction of major adverse cardiovascular events and cardiovascular mortality using this score. Approach and Results: We prospectively followed 3881 patients with adult heterozygous FH with no prior history of ASCVD (32 361 person-years of follow-up) from 5 registries in Europe and North America. The FH-Risk-Score incorporates 7 clinical variables: sex, age, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, hypertension, smoking, and lipoprotein (a) (Lp(a)) with a Harrell C-index for 10-year ASCVD event of 0.75, which was superior to the SAFEHEART-RE (Spanish Familial Hypercholesterolemia Cohort; 0.69). Subjects with an elevated FH-Risk-Score had decreases in 10-year ASCVD-free survival, 10-year major adverse cardiovascular event-free survival, and 30-year survival for CV mortality compared with the low-risk group, with hazard ratios of 5.52 (3.94-7.73), 4.64 (2.66-8.11), and 10.73 (2.51-45.79), respectively. The FH-Risk-Score showed a similar performance in subjects with and without an FH-causing mutation. Conclusions: The FH-Risk-Score is a stronger predictor of future ASCVD than the SAFEHEART-RE and was developed in FH subjects with no prior cardiovascular event. Furthermore, the FH-Risk-Score is the first score to predict CV death and could offer personalized cardiovascular risk assessment and treatment for patients with FH. Future studies are required to validate the FH-Risk-Score in different ethnic groups.

Prevalence of Familial Hypercholesterolemia Among the General Population and Patients With Atherosclerotic Cardiovascular Disease: A Systematic Review and Meta-Analysis.

BACKGROUND: Contemporary studies suggest that familial hypercholesterolemia (FH) is more frequent than previously reported and increasingly recognized as affecting individuals of all ethnicities and across many regions of the world. Precise estimation of its global prevalence and prevalence across World Health Organization regions is needed to inform policies aiming at early detection and atherosclerotic cardiovascular disease (ASCVD) prevention. The present study aims to provide a comprehensive assessment and more reliable estimation of the prevalence of FH than hitherto possible in the general population (GP) and among patients with ASCVD. METHODS: We performed a systematic review and meta-analysis including studies reporting on the prevalence of heterozygous FH in the GP or among those with ASCVD. Studies reporting gene founder effects and focused on homozygous FH were excluded. The search was conducted through Medline, Embase, Cochrane, and Global Health, without time or language restrictions. A random-effects model was applied to estimate the overall pooled prevalence of FH in the general and ASCVD populations separately and by World Health Organization regions. RESULTS: From 3225 articles, 42 studies from the GP and 20 from populations with ASCVD were eligible, reporting on 7 297 363 individuals/24 636 cases of FH and 48 158 patients/2827 cases of FH, respectively. More than 60% of the studies were from Europe. Use of the Dutch Lipid Clinic Network criteria was the commonest diagnostic method. Within the GP, the overall pooled prevalence of FH was 1:311 (95% CI, 1:250-1:397; similar between children [1:364] and adults [1:303], P=0.60; across World Health Organization regions where data were available, P=0.29; and between population-based and electronic health records-based studies, P=0.82). Studies with ≤10 000 participants reported a higher prevalence (1:200-289) compared with larger cohorts (1:365-407; P<0.001). The pooled prevalence among those with ASCVD was 18-fold higher than in the GP (1:17 [95% CI, 1:12-1:24]), driven mainly by coronary artery disease (1:16; [95% CI, 1:12-1:23]). Between-study heterogeneity was large (I2>95%). Tests assessing bias were nonsignificant (P>0.3). CONCLUSIONS: With an overall prevalence of 1:311, FH is among the commonest genetic disorders in the GP, similarly present across different regions of the world, and is more frequent among those with ASCVD. The present results support the advocacy for the institution of public health policies, including screening programs, to identify FH early and to prevent its global burden.

Evidence for improved survival with treatment of homozygous familial hypercholesterolemia.

PURPOSE OF REVIEW: Homozygous familial hypercholesterolemia (HoFH) is an orphan disease caused by biallelic mutations at the LDL receptor (LDLR) gene, with a prevalence estimated at 1 : 250 000 to 1 : 630 000. HoFH is characterized by extremely elevated plasma levels of LDL-C greater than 10 mmol/l (>387 mg/dl), tendinous and cutaneous xanthomas in youth and premature atherosclerotic cardiovascular disease (ASCVD). The expected prevalence varies from country to country depending on the presence of founder effects, genetic probability and life expectancy. Untreated, HoFH is a fatal condition before age 30. Plasma levels of LDL-C are the major cause of mortality and the therapeutic target. Statin therapy led to a remarkable improvement in survival but is of limited use in loss-of-function LDLR gene variants or 'null' mutations. Inhibitors of PCSK9 are a useful adjunct in patients with LDLR mutations with residual activity. Extracorporeal LDL filtration has improved survival since its introduction three decades ago. RECENT FINDINGS: Novel therapies, not dependent on a functioning LDLR include lomitapide and mipomersen, which decrease hepatic apolipoprotein B secretion, and evinacumab, directed at the angiopoietin like-3 protein (ANGPLT-3). SUMMARY: Over the past 3-4 decades, the survival of patients with HoFH has increased markedly. New therapeutic options offer new hope.

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease.

BACKGROUND: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. METHODS: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1ß, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P=0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P=0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P=0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P=0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P=0.31). CONCLUSIONS: Antiinflammatory therapy targeting the interleukin-1ß innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846 .).

Desmocollin 1 is abundantly expressed in atherosclerosis and impairs high-density lipoprotein biogenesis.

Aims: The biogenesis of high-density lipoprotein (HDL) particles by cholesterol-laden foam cells in atherosclerotic lesions is crucial for the removal of excess cholesterol from the lesions. Impairment in the HDL biogenic process contributes to the progression of atherosclerosis. The aim of this study is to identify novel cellular factors regulating HDL biogenesis. Methods and results: HDL biogenesis is a process of apolipoprotein (apo)-mediated solubilization of specific plasma membrane (PM) microdomains generated in cholesterol-accumulated cells. We established a new method to isolate PM microdomains interacting with the major HDL protein constituent, apoA-I. Lipidomic and proteomic analyses of an isolated PM microdomain revealed that apoA-I binds to cholesterol-rich and desmocollin 1 (DSC1)-containing microdomains. In this novel apoA-I binding microdomain, DSC1 binds and prevents apoA-I from interacting with another PM microdomain created by adenosine triphosphate-binding cassette transporter A1 (ABCA1) for the formation of HDL. Inhibition of apoA-I-DSC1 binding by silencing DSC1 expression or using DSC1 blocking antibodies increases apoA-I accessibility to ABCA1-created microdomains and thus enhances HDL biogenesis. Importantly, DSC1 is abundantly expressed in macrophages and human atherosclerotic lesions, suggesting that DSC1 may contribute to cholesterol accumulation in atherosclerotic lesions by sequestering apoA-I and impairing HDL biogenesis. Conclusions: The binding of apoA-I to two functionally opposing PM microdomains, ABCA1 and DSC1 domains, suggests that HDL biogenesis and PM cholesterol levels may be regulated by the relative abundance of the two domains and that novel HDL biogenic therapies may be developed by targeting DSC1.

Familial hypercholesterolemia: experience from the French-Canadian population.

PURPOSE OF REVIEW: There has recently been renewed interest in the study of the various facets of familial hypercholesterolemia, a severe monogenic disease associated with elevated LDL-cholesterol and premature cardiovascular disease (CVD). In the present review, novel data presenting the frequency of familial hypercholesterolemia as well as factors modulating the cardiovascular risk in familial hypercholesterolemia will be discussed. RECENT FINDINGS: Recent studies have showed that familial hypercholesterolemia is much more prevalent than initially thought. Classically, it was estimated that familial hypercholesterolemia affected one in 500 people worldwide, but a recent large-scale meta-analysis has shown a prevalence closer to one in 250. In the French-Canadian population, this disease is even more frequent reaching one in 81 in certain regions of the Province of Quebec. Several novel studies in the French-Canadian population have shown that the clinical outcomes in familial hypercholesterolemia seem to be greatly influenced by risk factors other than LDL-cholesterol. Also, scores to predict CVD in familial hypercholesterolemia have been recently proposed. SUMMARY: Familial hypercholesterolemia is more frequent than initially thought and the phenotype of this disease can be variable. Indeed, both clinical and genetic variables can modulate the CVD risk in this population.

Membrane microdomains and the regulation of HDL biogenesis.

PURPOSE OF REVIEW: The major cardio-protective function of HDL is to remove excess cellular cholesterol in the process of HDL particle formation and maturation. The HDL biogenic procedure requiring protein-lipid interactions has been incompletely understood, and here we discuss recent progress and insights into the mechanism of HDL biogenesis. RECENT FINDINGS: The initial and rate-limiting step of HDL biogenesis is the interaction between apoA-I and plasma membrane microdomains created by ATP-binding cassette transporter A1 (ABCA1) transporter. Computer simulation of molecular dynamics suggests that ABCA1 translocates phospholipids from the inner to the outer leaflet of the plasma membrane to create a transbilayer density gradient leading to the formation of an exovesiculated plasma membrane microdomain. The cryo-electron microscopy structure of ABCA1 suggests that an elongated hydrophobic tunnel formed by the extracellular domain of ABCA1 may function as a passageway to deliver lipids to apoA-I. In contrast to ABCA1-created plasma membrane microdomains, desmocollin 1 (DSC1) contained in a cholesterol-rich plasma membrane microdomain binds apoA-I to prevent HDL biogenesis. The identification of DSC1-containing plasma membrane microdomains as a negative regulator of HDL biogenesis may offer potential therapeutic avenues. SUMMARY: Isolation and characterization of plasma membrane microdomains involved in HDL biogenesis may lead to a better understanding of the molecular mechanism of HDL biogenesis.

Pooled Safety Analysis of Evolocumab in Over 6000 Patients From Double-Blind and Open-Label Extension Studies.

BACKGROUND: Evolocumab, a fully human monoclonal antibody to PCSK9 (proprotein convertase subtilisin/kexin type 9), markedly reduces low-density lipoprotein cholesterol across diverse patient populations. The objective of this study was to assess the safety and tolerability of evolocumab in a pooled safety analysis from phase 2 or 3 randomized and placebo or comparator-controlled trials (integrated parent trials) and the first year of open-label extension (OLE) trials that included a standard-of-care control group. METHODS: This analysis included adverse event (AE) data from 6026 patients in 12 phase 2 and 3 parent trials, with a median exposure of 2.8 months, and, of those patients, from 4465 patients who continued with a median follow-up of 11.1 months in 2 OLE trials. AEs were analyzed separately for the parent and OLE trials. Overall AE rates, serious AEs, laboratory assessments, and AEs of interest were evaluated. RESULTS: Overall AE rates were similar between evolocumab and control in the parent trials (51.1% versus 49.6%) and in year 1 of OLE trials (70.0% versus 66.0%), as were those for serious AEs. Elevations of serum transaminases, bilirubin, and creatine kinase were infrequent and similar between groups. Muscle-related AEs were similar between evolocumab and control. Neurocognitive AEs were infrequent and balanced during the double-blind parent studies (5 events [0.1%], evolocumab groups versus 6 events [0.3%], control groups). In the OLE trials, 27 patients (0.9%) in the evolocumab groups and 5 patients (0.3%) in the control groups reported neurocognitive AEs. No neutralizing antievolocumab antibodies were detected. CONCLUSIONS: Overall, this integrated safety analysis of 6026 patients pooled across phase 2/3 trials and 4465 patients who continued in OLE trials for 1 year supports a favorable benefit-risk profile for evolocumab.

Imputation of Baseline LDL Cholesterol Concentration in Patients with Familial Hypercholesterolemia on Statins or Ezetimibe.

BACKGROUND: Familial hypercholesterolemia (FH) is the most frequent genetic disorder seen clinically and is characterized by increased LDL cholesterol (LDL-C) (>95th percentile), family history of increased LDL-C, premature atherosclerotic cardiovascular disease (ASCVD) in the patient or in first-degree relatives, presence of tendinous xanthomas or premature corneal arcus, or presence of a pathogenic mutation in the LDLR, PCSK9, or APOB genes. A diagnosis of FH has important clinical implications with respect to lifelong risk of ASCVD and requirement for intensive pharmacological therapy. The concentration of baseline LDL-C (untreated) is essential for the diagnosis of FH but is often not available because the individual is already on statin therapy. METHODS: To validate a new algorithm to impute baseline LDL-C, we examined 1297 patients. The baseline LDL-C was compared with the imputed baseline obtained within 18 months of the initiation of therapy. We compared the percent reduction in LDL-C on treatment from baseline with the published percent reductions. RESULTS: After eliminating individuals with missing data, nonstandard doses of statins, or medications other than statins or ezetimibe, we provide data on 951 patients. The mean ± SE baseline LDL-C was 243.0 (2.2) mg/dL [6.28 (0.06) mmol/L], and the mean ± SE imputed baseline LDL-C was 244.2 (2.6) mg/dL [6.31 (0.07) mmol/L] (P = 0.48). There was no difference in response according to the patient's sex or in percent reduction between observed and expected for individual doses or types of statin or ezetimibe. CONCLUSIONS: We provide a validated estimation of baseline LDL-C for patients with FH that may help clinicians in making a diagnosis.

HDLs and the pathogenesis of atherosclerosis.

PURPOSE OF REVIEW: Plasma levels of HDL cholesterol are a biomarker of cardiovascular health but not a therapeutic target, as demonstrated by the failure of pharmacological modulation of HDL cholesterol to prevent or treat atherosclerotic cardiovascular disease. In health, HDL particles exert pleiotropic effects against atherosclerosis, including cholesterol removal from foam cells, vasodilatory effects through vascular endothelial cell nitric oxide production, decreased vascular inflammation and oxidative damage, endothelial cell proliferation and antiapoptotic effects. RECENT FINDINGS: These functional effects of HDL are independent of the cholesterol mass and are related to the proteome and lipidome. In disease states and with the ageing process, HDL components are extensively modified and may no longer play a beneficial role but are retained in the atheroma and contribute to atherosclerosis. We have recently shown that desmocollin 1 (DSC1) acts as an apolipoprotein (apo) A-I binding protein that is highly expressed in atherosclerotic plaques and inhibits atheroprotective HDL functions by retaining apoA-I. The apoA-I retention hypothesis proposes that macrophages express DSC1 in a maladaptive process that renders apoA-I inactive and contributes to atherosclerosis. SUMMARY: HDL loses their beneficial properties in ageing and disease states. Novel pathways may present new therapeutic avenues to restore their biological functions.

[Screening for atherosclerosis to prevent cardiovascular risk : a pro-contra debate]. / Dépistage de l'athérosclérose pour prévenir le risque cardiovasculaire : un débat pro-contre.

Detecting atherosclerosis using imaging techniques is the subject of intense debate in the scientific community. Among the arguments in favor of screening, a better identification or better stratification of cardiovascular risk is mentioned, compared to cardiovascular risk scores based solely on traditional risk factors, such as blood pressure or cholesterol levels. Imaging techniques are also used to monitor the progression of atherosclerosis among patients using lipid-lowering or antihypertensive drugs in primary prevention. However, several experts in recent years have challenged the clinical utility of these imaging techniques in asymptomatic adults. This article proposes a debate « for or against ¼ to describe the main arguments for or against the use of imaging for screening for atherosclerosis.

Dépister l'athérosclérose par des techniques d'imagerie fait l'objet d'intenses débats dans la communauté scientifique. Parmi les arguments en faveur du dépistage, une meilleure identification ou une meilleure stratification du risque cardiovasculaire est évoquée par rapport aux scores de risque cardiovasculaire basés uniquement sur les facteurs de risque traditionnels, tels que la tension artérielle ou le taux de cholestérol. Les techniques d'imagerie sont également utilisées pour le suivi de la progression de l'athérosclérose sous traitement hypolipémiant ou antihypertenseur en prévention primaire. Cependant, l'utilité clinique de ces imageries chez les adultes asymptomatiques a été contestée par plusieurs experts ces dernières années. Cet article propose un débat « pour ou contre ¼ pour décrire les principaux arguments en faveur ou contre l'utilisation de l'imagerie pour le dépistage de l'athérosclérose.

Novel Approaches for HDL-Directed Therapies.

PURPOSE OF REVIEW: High-density lipoproteins (HDL) are thought to exert a protective role against atherosclerosis. The measurement of the cholesterol mass within HDL (HDL-C) represents a good biomarker of cardiovascular health, but HDL-C appears to be a poor therapeutic target. Here, we discuss new targets for the development of HDL-directed therapies. RECENT FINDINGS: Among cardio-protective functions of HDL particles, the ability of HDL to remove cholesterol from cells involved in the early stages of atherosclerosis is considered one of the most important functions. This process, termed "HDL biogenesis," is initiated by the formation of highly specialized plasma membrane micro-domains by the ATP-binding cassette transporter A1 (ABCA1) and the binding of apolipoproteins (apo) such as apoA-I, the major protein moiety of HDL, to the micro-domains. Although early strategies aimed at increasing HDL biogenesis by upregulating ABCA1 or apoA-I gene expression have not met with clinical success, recent advances in understanding transcriptional, post-transcriptional, and post-translational regulatory pathways propose new targets for the promotion of HDL biogenesis. We have recently reported that a novel apoA-I-binding protein desmocollin 1 (DSC1) prevents HDL biogenesis and that inhibition of apoA-I-DSC1 interactions promotes HDL biogenesis by stabilizing ABCA1. This new HDL regulation pathway nominates DSC1 as an attractive pharmacological target. In the absence of clinically useful therapy to increase HDL biogenesis, finding novel targets to unlock the therapeutic potential of HDL is highly desired. Modulation of apoA-I-DSC1 interactions may be a viable strategy.

Apolipoprotein E derived HDL mimetic peptide ATI-5261 promotes nascent HDL formation and reverse cholesterol transport in vitro.

Modulation of the reverse cholesterol transport (RCT) pathway may provide a therapeutic target for the prevention and treatment of atherosclerotic cardiovascular disease (CVD). In the present study, we evaluated a novel 26-amino acid apolipoprotein mimetic peptide (ATI-5261) designed from the carboxyl terminal of apoE, in its ability to mimic apoA-I functionality in RCT in vitro. Our data shows that nascent HDL-like (nHDL) particles generated by incubating cells over-expressing ABCA1 with ATI-5261 increase the rate of specific ABCA1 dependent lipid efflux, with high affinity interactions with ABCA1. We also show that these nHDL particles interact with membrane micro-domains in a manner similar to nHDL apoA-I. These nHDL particles then interact with the ABCG1 transporter and are remodeled by plasma HDL-modulating enzymes. Finally, we show that these mature HDL-like particles are taken up by SR-BI for cholesterol delivery to liver cells. This ATI-5621-mediated process mimics apoA-I and may provide a means to prevent cholesterol accumulation in the artery wall. In this study, we propose an integrative physiology approach of HDL biogenesis with the synthetic peptide ATI-5261. These experiments provide new insights for potential therapeutic use of apolipoprotein mimetic peptides.

Apolipoprotein A-I truncations in Chagas disease are caused by cruzipain, the major cysteine protease of Trypanosoma cruzi.

Trypanosoma cruzi is the etiologic agent of Chagas disease. Approximately 10 million people are infected worldwide. We have previously reported that in individuals infected with T. cruzi, apolipoprotein A-I (Apo A-I), the major structural component of host high-density lipoprotein, was truncated into fragments that are specific to Chagas disease and have the potential to be used as diagnostic biomarkers. We investigated the possibility that cruzipain, the major cysteine protease of T. cruzi, is responsible for truncating host Apo A-I. We found that due to Apo A-I truncation, the high-density lipoprotein subspecies profile is altered in individuals with Chagas disease compared with healthy controls. Western blot analysis revealed that both purified Apo A-I protein and Apo A-I in the high-density lipoprotein complex were susceptible to cruzipain cleavage, and the sizes of the truncation product in the latter matched the sizes of Apo A-I biomarkers. We also found that in vitro feeding T. cruzi-infected differentiated human adipocytes with purified human high-density lipoprotein led to the appearance of the biomarker fragments of Apo A-I. Cruzipain is found both on the cytoplasmic membrane and in the internal lysosomal structure of T. cruzi. We demonstrate that cruzipain from both sources contributes to the production of Apo A-I truncation in the biomarker set.