Homozygous familial hypercholesterolaemia: new insights and guidance for clinicians to improve detection and clinical management. A position paper from the Consensus Panel on Familial Hypercholesterolaemia of the European Atherosclerosis Society

Metabolic systems approaches update molecular insights of clinical phenotypes and cardiovascular risk in patients with homozygous familial hypercholesterolemia

BACKGROUND

Homozygous familial hypercholesterolemia (HoFH) is an orphan metabolic disease characterized by extremely elevated low-density lipoprotein cholesterol (LDL-C), xanthomas, aortic stenosis, and premature atherosclerotic cardiovascular disease (ASCVD). In addition to LDL-C, studies in experimental models and small clinical populations have suggested that other types of metabolic molecules might also be risk factors responsible for cardiovascular complications in HoFH, but definitive evidence from large-scale human studies is still lacking. Herein, we aimed to comprehensively characterize the metabolic features and risk factors of human HoFH by using metabolic systems strategies.

METHODS

Two independent multi-center cohorts with a total of 868 individuals were included in the cross-sectional study. First, comprehensive serum metabolome/lipidome-wide analyses were employed to identify the metabolomic patterns for differentiating HoFH patients (n = 184) from heterozygous FH (HeFH, n = 376) and non-FH (n = 100) subjects in the discovery cohort. Then, the metabolomic patterns were verified in the validation cohort with 48 HoFH patients, 110 HeFH patients, and 50 non-FH individuals. Subsequently, correlation/regression analyses were performed to investigate the associations of clinical/metabolic alterations with typical phenotypes of HoFH. In the prospective study, a total of 84 HoFH patients with available follow-up were enrolled from the discovery cohort. Targeted metabolomics, deep proteomics, and random forest approaches were performed to investigate the ASCVD-associated biomarkers in HoFH patients.

RESULTS

Beyond LDL-C, various bioactive metabolites in multiple pathways were discovered and validated for differentiating HoFH from HoFH and non-FH. Our results demonstrated that the inflammation and oxidative stress-related metabolites in the pathways of arachidonic acid and lipoprotein(a) metabolism were independently associated with the prevalence of corneal arcus, xanthomas, and supravalvular/valvular aortic stenosis in HoFH patients. Our results also identified a small marker panel consisting of high-density lipoprotein cholesterol, lipoprotein(a), apolipoprotein A1, and eight proinflammatory and proatherogenic metabolites in the pathways of arachidonic acid, phospholipid, carnitine, and sphingolipid metabolism that exhibited significant performances on predicting first ASCVD events in HoFH patients.

CONCLUSIONS

Our findings demonstrate that human HoFH is associated with a variety of metabolic abnormalities and is more complex than previously known. Furthermore, this study provides additional metabolic alterations that hold promise as residual risk factors in HoFH population.

Large-Scale CRISPR Screen of LDLR Pathogenic Variants

Familial hypercholesterolemia (FH) is a frequently occurring genetic disorder that is linked to early-onset cardiovascular disease. If left untreated, patients with this condition can develop severe cardiovascular complications. Unfortunately, many patients remain undiagnosed, and even when diagnosed, the treatment is often not optimal. Although mutations in the LDLR gene are the primary cause of FH, predicting whether novel variants are pathogenic is not a straightforward task. Understanding the functionality of LDLR variants is crucial in uncovering the genetic basis of FH. Our study utilized CRISPR/Cas9 cytosine base editors in pooled screens to establish a novel approach for functionally assessing tens of thousands of LDLR variants on a large scale. A total of more than 100 single guide RNAs (sgRNAs) targeting LDLR pathogenic mutations were successfully screened with relatively high accuracy. Out of these, 5 sgRNAs were further subjected to functional verification studies, including 1 in the promoter, 1 in the antisense RNA, 1 in the exon, and 2 in the intron. Except for the variant caused by the sgRNA located at intron 16, the functionalities of the other LDLR variants were all downregulated. The high similarity of LDLR intron sequences may lead to some false positives. Overall, these results confirm the reliability of the large-scale screening strategy for functional analysis of LDLR variants, and the screened candidate pathogenic mutations could be used as an auxiliary means of clinical gene detection to prevent FH-induced heart disease.

A systematic review and meta-analysis of the prevalence of dyslipidaemia among adults in Malaysia

Dyslipidaemia is an established cardiovascular risk factor. This study aimed to determine the pooled prevalence of dyslipidaemia in Malaysian adults. A systematic review and meta-analysis of all cross-sectional, longitudinal observational studies which reported the prevalence of elevated total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), triglycerides (TG), and reduced high-density lipoprotein cholesterol (HDL-c) in adults 18 years old and older, was conducted. A comprehensive search of PubMed and Cochrane Central Register of Controlled Trials (which included Medline, EMBASE and major trial registers) from inception to October 18, 2022, was performed. Risk-of-bias was evaluated using the Johanna-Briggs Institute Prevalence Critical Appraisal Tool, while certainty of evidence was assessed using an adapted version of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework. Random-effects meta-analyses were performed using MetaXL. This report follows the PRISMA reporting guidelines. The protocol was registered with PROSPERO (CRD42020200281). 26 556 studies were retrieved and 7 941 were shortlisted initially. From this, 70 Malaysian studies plus two studies from citation searching were shortlisted; 46 were excluded, and 26 were included in the review (n = 50 001). The pooled prevalence of elevated TC (≥ 5.2 mmol/L), elevated LDL-c (≥ 2.6 mmol/L), elevated TG (≥ 1.7 mmol/L), and low HDL-c (< 1.0 mmol/L in men and < 1.3 mmol/L in women) were 52% (95% CI 32-71%, I2 = 100%), 73% (95% CI 50-92%, I2 = 100%), 36% (95% CI 32-40%, I2 = 96%), and 40% (95% CI 25-55%, I2 = 99%), respectively. This review found that the prevalence of all dyslipidaemia subtypes is high in Malaysian adults. Ongoing efforts to reduce cardiovascular diseases in Malaysia should integrate effective detection and treatment of dyslipidaemia.

Gene Therapy for Paediatric Homozygous Familial Hypercholesterolaemia

The clinical outcome for children and adolescents with homozygous familial hypercholesterolaemia (HoFH) can be devastating, and treatment options are limited in the presence of a null variant. In HoFH, atherosclerotic risk accumulates from birth. Gene therapy is an appealing treatment option as restoration of low-density lipoprotein receptor (LDLR) gene function could provide a cure for HoFH. A clinical trial using a recombinant adeno-associated vector (rAAV) to deliver LDLR DNA to adult patients with HoFH was recently completed; results have not yet been reported. However, this treatment strategy may face challenges when translating to the paediatric population. The paediatric liver undergoes substantial growth which is significant as rAAV vector DNA persists primarily as episomes (extra-chromosomal DNA) and are not replicated during cell division. Therefore, rAAV-based gene addition treatment administered in childhood would likely only have a transient effect. With over 2,000 unique variants in LDLR, a goal of genomic editing-based therapy development would be to treat most (if not all) mutations with a single set of reagents. For a robust, durable effect, LDLR must be repaired in the genome of hepatocytes, which could be achieved using genomic editing technology such as clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 and a DNA repair strategy such as homology-independent targeted integration. This review discusses this issue in the context of the paediatric patient group with severe compound heterozygous or homozygous null variants which are associated with aggressive early-onset atherosclerosis and myocardial infarction, together with the important pre-clinical studies that use genomic editing strategies to treat HoFH in place of apheresis and liver transplantation.

The Beneficial Effect of Lomitapide on the Cardiovascular System in LDLr-/- Mice with Obesity

OBJECTIVES

Homozygous familial hypercholesteremia (HoFH) is a rare, life-threatening metabolic disease, mainly caused by a mutation in the LDL receptor. If untreated, HoFH causes premature death from acute coronary syndrome. Lomitapide is approved by the FDA as a therapy to lower lipid levels in adult patients with HoFH. Nevertheless, the beneficial effect of lomitapide in HoFH models remains to be defined. In this study, we investigated the effect of lomitapide on cardiovascular function using LDL receptor-knockout mice (LDLr-/-).

METHODS

Six-week-old LDLr-/- mice were fed a standard diet (SD) or a high-fat diet (HFD) for 12 weeks. Lomitapide (1 mg/Kg/Day) was given by oral gavage for the last 2 weeks in the HFD group. Body weight and composition, lipid profile, blood glucose, and atherosclerotic plaques were measured. Vascular reactivity and markers for endothelial function were determined in conductance arteries (thoracic aorta) and resistance arteries (mesenteric resistance arteries (MRA)). Cytokine levels were measured by using the Mesoscale discovery V-Plex assays.

RESULTS

Body weight (47.5 ± 1.5 vs. 40.3 ± 1.8 g), % of fat mass (41.6 ± 1.9% vs. 31.8 ± 1.7%), blood glucose (215.5 ± 21.9 vs. 142.3 ± 7.7 mg/dL), and lipid levels (cholesterol: 600.9 ± 23.6 vs. 451.7 ± 33.4 mg/dL; LDL/VLDL: 250.6 ± 28.9 vs. 161.1 ± 12.24 mg/dL; TG: 299.5 ± 24.1 vs. 194.1 ± 28.1 mg/dL) were significantly decreased, and the % of lean mass (56.5 ± 1.8% vs. 65.2 ± 2.1%) was significantly increased in the HFD group after lomitapide treatment. The atherosclerotic plaque area also decreased in the thoracic aorta (7.9 ± 0.5% vs. 5.7 ± 0.1%). After treatment with lomitapide, the endothelium function of the thoracic aorta (47.7 ± 6.3% vs. 80.7 ± 3.1%) and mesenteric resistance artery (66.4 ± 4.3% vs. 79.5 ± 4.6%) was improved in the group of LDLr-/- mice on HFD. This was correlated with diminished vascular endoplasmic (ER) reticulum stress, oxidative stress, and inflammation.

CONCLUSIONS

Treatment with lomitapide improves cardiovascular function and lipid profile and reduces body weight and inflammatory markers in LDLr-/- mice on HFD.

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

BACKGROUND

Familial hypercholesterolemia (FH) is predominantly caused by mutations in the 4 FH candidate genes (FHCGs), namely, low-density lipoprotein receptor (LDLR), apolipoprotein B-100 (APOB-100), proprotein convertase subtilisin/kexin type 9 (PCSK9), and the LDL receptor adaptor protein 1 (LDLRAP1). It is characterized by elevated low-density lipoprotein cholesterol (LDL-c) levels leading to premature coronary artery disease. FH can be clinically diagnosed using established clinical criteria, namely, Simon Broome (SB) and Dutch Lipid Clinic Criteria (DLCC), and can be identified using the Familial Hypercholesterolemia Case Ascertainment Tool (FAMCAT), a primary care screening tool.

OBJECTIVE

This study aims to (1) compare the detection rate of genetically confirmed FH and diagnostic accuracy between the FAMCAT, SB, and DLCC in the Malaysian primary care setting; (2) identify the genetic mutation profiles, including novel variants, in individuals with suspected FH in primary care; (3) explore the experience, concern, and expectation of individuals with suspected FH who have undergone genetic testing in primary care; and (4) evaluate the clinical utility of a web-based FH Identification Tool that includes the FAMCAT, SB, and DLCC in the Malaysian primary care setting.

METHODS

This is a mixed methods evaluation study conducted in 11 Ministry of Health primary care clinics located at the central administrative region of Malaysia. In Work stream 1, the diagnostic accuracy study design is used to compare the detection rate and diagnostic accuracy of the FAMCAT, SB, and DLCC against molecular diagnosis as the gold standard. In Work stream 2, the targeted next-generation sequencing of the 4 FHCGs is used to identify the genetic mutation profiles among individuals with suspected FH. In Work stream 3a, a qualitative semistructured interview methodology is used to explore the experience, concern, and expectation of individuals with suspected FH who have undergone genetic testing. Lastly, in Work stream 3b, a qualitative real-time observation of primary care physicians using the "think-aloud" methodology is applied to evaluate the clinical utility of a web-based FH Identification Tool.

RESULTS

The recruitment for Work stream 1, and blood sampling and genetic analysis for Work stream 2 were completed in February 2023. Data collection for Work stream 3 was completed in March 2023. Data analysis for Work streams 1, 2, 3a, and 3b is projected to be completed by June 2023, with the results of this study anticipated to be published by December 2023.

CONCLUSIONS

This study will provide evidence on which clinical diagnostic criterion is the best to detect FH in the Malaysian primary care setting. The full spectrum of genetic mutations in the FHCGs including novel pathogenic variants will be identified. Patients' perspectives while undergoing genetic testing and the primary care physicians experience in utilizing the web-based tool will be established. These findings will have tremendous impact on the management of patients with FH in primary care and subsequently reduce their risk of premature coronary artery disease.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/47911.

Role of non-coding variants in cardiovascular disease

Cardiovascular diseases (CVDs) constitute one of the significant causes of death worldwide. Different pathological states are linked to CVDs, which despite interventions and treatments, still have poor prognoses. The genetic component, as a beneficial tool in the risk stratification of CVD development, plays a role in the pathogenesis of this group of diseases. The emergence of genome-wide association studies (GWAS) have led to the identification of non-coding parts associated with cardiovascular traits and disorders. Variants located in functional non-coding regions, including promoters/enhancers, introns, miRNAs and 5'/3' UTRs, account for 90% of all identified single-nucleotide polymorphisms associated with CVDs. Here, for the first time, we conducted a comprehensive review on the reported non-coding variants for different CVDs, including hypercholesterolemia, cardiomyopathies, congenital heart diseases, thoracic aortic aneurysms/dissections and coronary artery diseases. Additionally, we present the most commonly reported genes involved in each CVD. In total, 1469 non-coding variants constitute most reports on familial hypercholesterolemia, hypertrophic cardiomyopathy and dilated cardiomyopathy. The application and identification of non-coding variants are beneficial for the genetic diagnosis and better therapeutic management of CVDs.

GalNAc-Lipid nanoparticles enable non-LDLR dependent hepatic delivery of a CRISPR base editing therapy

Lipid nanoparticles have demonstrated utility in hepatic delivery of a range of therapeutic modalities and typically deliver their cargo via low-density lipoprotein receptor-mediated endocytosis. For patients lacking sufficient low-density lipoprotein receptor activity, such as those with homozygous familial hypercholesterolemia, an alternate strategy is needed. Here we show the use of structure-guided rational design in a series of mouse and non-human primate studies to optimize a GalNAc-Lipid nanoparticle that allows for low-density lipoprotein receptor independent delivery. In low-density lipoprotein receptor-deficient non-human primates administered a CRISPR base editing therapy targeting the ANGPTL3 gene, the introduction of an optimized GalNAc-based asialoglycoprotein receptor ligand to the nanoparticle surface increased liver editing from 5% to 61% with minimal editing in nontargeted tissues. Similar editing was noted in wild-type monkeys, with durable blood ANGPTL3 protein reduction up to 89% six months post dosing. These results suggest that GalNAc-Lipid nanoparticles may effectively deliver to both patients with intact low-density lipoprotein receptor activity as well as those afflicted by homozygous familial hypercholesterolemia.

Referral rate, profile and degree of control of patients with familial hypercholesterolemia: data from a single lipid unit from a Mediterranean area

BACKGROUND

The challenging rigorous management of hypercholesterolemia promotes referral to specialized units. This study explored the need, based on referral rate and cardiovascular (CV) risk factor control in patients evaluated for familial hypercholesterolemia (FH), for a lipid unit (LU).

METHODS

Over a four-year period, 340 referrals to our unit were analyzed to establish the lipid disorder referral rate. Moreover, 118 patients referred for potential FH during the period 2010-2018 (52.4 ± 13.9 years, 47.5% male, Caucasian, 26.3% obese, 33.1% smokers and 51.7% with some glycaemic alteration) were investigated. The Dutch Lipid Clinic Network (DLCN) score, type and dose of lipid-lowering drugs, lipid profile including lipoprotein (a) (Lp(a)) and the presence of plaques with carotid ultrasound (CU) were recorded.

RESULTS

Lipids represented 6.2% of referrals (38 patient-years) requiring a 2-3 h weekly monographic outpatient consultation. The potential FH sample displayed a DLCN score ≥ 6 in 78% and modifiable CV risk factors in 51%. Only 22% achieved tight disease control despite intensive treatment. The statin-ezetimibe combination treatment group achieved better goals (73.0% vs. 45.5%, P = 0.003), and the rosuvastatin group had a higher proportion of prediabetes (60.9% vs. 39.1%, P = 0.037). Neither CU plaque presence nor Lp(a) > 50 mg/dL was linked with established CV disease patients, but higher Lp(a) concentrations were detected between them (102.5 (26.3-145.8) vs. 25.0 (13.0-52.0) mg/dL, P = 0.012).

CONCLUSIONS

The referral rate, degree of control, and proportion of modifiable CV risk factors in FH patients demonstrate the need for LU in our area as well as optimize control and treatment.

2023 Update on European Atherosclerosis Society Consensus Statement on Homozygous Familial Hypercholesterolaemia: new treatments and clinical guidance

This 2023 statement updates clinical guidance for homozygous familial hypercholesterolaemia (HoFH), explains the genetic complexity, and provides pragmatic recommendations to address inequities in HoFH care worldwide. Key strengths include updated criteria for the clinical diagnosis of HoFH and the recommendation to prioritize phenotypic features over genotype. Thus, a low-density lipoprotein cholesterol (LDL-C) >10 mmol/L (>400 mg/dL) is suggestive of HoFH and warrants further evaluation. The statement also provides state-of-the art discussion and guidance to clinicians for interpreting the results of genetic testing and for family planning and pregnancy. Therapeutic decisions are based on the LDL-C level. Combination LDL-C-lowering therapy-both pharmacologic intervention and lipoprotein apheresis (LA)-is foundational. Addition of novel, efficacious therapies (i.e. inhibitors of proprotein convertase subtilisin/kexin type 9, followed by evinacumab and/or lomitapide) offers potential to attain LDL-C goal or reduce the need for LA. To improve HoFH care around the world, the statement recommends the creation of national screening programmes, education to improve awareness, and management guidelines that account for the local realities of care, including access to specialist centres, treatments, and cost. This updated statement provides guidance that is crucial to early diagnosis, better care, and improved cardiovascular health for patients with HoFH worldwide.

Contemporary Homozygous Familial Hypercholesterolemia in the United States: Insights From the CASCADE FH Registry

Background Homozygous familial hypercholesterolemia (HoFH) is a rare, treatment-resistant disorder characterized by early-onset atherosclerotic and aortic valvular cardiovascular disease if left untreated. Contemporary information on HoFH in the United States is lacking, and the extent of underdiagnosis and undertreatment is uncertain. Methods and Results Data were analyzed from 67 children and adults with clinically diagnosed HoFH from the CASCADE (Cascade Screening for Awareness and Detection) FH Registry. Genetic diagnosis was confirmed in 43 patients. We used the clinical characteristics of genetically confirmed patients with HoFH to query the Family Heart Database, a US anonymized payer health database, to estimate the number of patients with similar lipid profiles in a "real-world" setting. Untreated low-density lipoprotein cholesterol levels were lower in adults than children (533 versus 776 mg/dL; P=0.001). At enrollment, atherosclerotic cardiovascular disease and supravalvular and aortic valve stenosis were present in 78.4% and 43.8% and 25.5% and 18.8% of adults and children, respectively. At most recent follow-up, despite multiple lipid-lowering treatment, low-density lipoprotein cholesterol goals were achieved in only a minority of adults and children. Query of the Family Heart Database identified 277 individuals with profiles similar to patients with genetically confirmed HoFH. Advanced lipid-lowering treatments were prescribed for 18%; 40% were on no lipid-lowering treatment; atherosclerotic cardiovascular disease was reported in 20%; familial hypercholesterolemia diagnosis was uncommon. Conclusions Only patients with the most severe HoFH phenotypes are diagnosed early. HoFH remains challenging to treat. Results from the Family Heart Database indicate HoFH is systemically underdiagnosed and undertreated. Earlier screening, aggressive lipid-lowering treatments, and guideline implementation are required to reduce disease burden in HoFH.

Homozygous Familial Hypercholesterolemia in Canada: An Observational Study

Background

Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disease characterized by very high levels of low-density lipoprotein cholesterol (LDL-C). Untreated patients present with extensive xanthomas and premature atherosclerosis. Lipid-lowering therapy is highly efficacious and has dramatically increased life expectancy of patients with HoFH.

Objectives

The aim of the study was to obtain a comprehensive registry of HoFH in Canada, known to have several founder effect regions, and describe the clinical characteristics and cardiovascular outcomes of this population over time.

Methods

Clinical and genetic data on patients with HoFH were collected via a standardized questionnaire sent to academic sites participating in the Familial Hypercholesterolemia Canada network.

Results

A total of 48 patients with HoFH were enrolled. The median age at diagnosis was 12 years (interquartile range [IQR]: 5-24) and untreated LDL-C levels were 15.0 mmol/L (IQR: 10.5-18.6 mmol/L; 580 mg/dL IQR: 404-717 mg/dL). At last follow-up visit, median age was 40 years (IQR: 26-54 years). Treated LDL-C levels were 6.75 mmol/L (IQR: 4.73-9.51 mmol/L; 261 mg/dL IQR: 183-368 mg/dL) with 95.5% of patients on statins, 88.6% on ezetimibe, 34.1% on proprotein convertase subtilisin/kexin type 9 inhibitors, 27.3% on lomitapide, 13.6% on evinacumab, and 56.8% were treated with low-density lipoprotein apheresis or plasmapheresis. Deaths were reported in 7 (14.5%) and major adverse cardiovascular events were observed in 14.6% of patients with the average onset at 30 years (IQR: 20-36 years). Aortic stenosis was reported in one-half the patients (47.9%) and 10 (20.8%) underwent aortic valve replacement.

Conclusions

This HoFH patient registry in Canada will provide important new health-related knowledge about the phenotypic manifestations and determinants of cardiovascular risk in this population, allowing for closer examination of quality of life and burden to the health care system.

Treatment of Homozygous Familial Hypercholesterolemia With ANGPTL3 Inhibitor, Evinacumab

Homozygous familial hypercholesterolemia (HoFH) is an ultra-rare, life-threatening, genetic condition characterized by markedly elevated levels of low-density lipoprotein cholesterol (LDL-C). Standard lipid-lowering therapies minimally reduce LDL-C in these patients, and lifelong serial apheresis is the mainstay of treatment. Evinacumab is a monoclonal antibody against angiopoietin-like protein 3 that lowers LDL-C levels via a novel LDL receptor-independent mechanism, and is US Food and Drug Administration approved for HoFH in the United States. We present a pediatric HoFH patient from Ontario who has been receiving evinacumab through special access from Health Canada. A 17-year-old boy was diagnosed with severe HoFH due to compound heterozygous LDLR pathogenic variants. Treatment has included a statin, ezetimibe, and LDL apheresis every 2 weeks, with minimal overall effect on LDL-C levels. He remains asymptomatic from a cardiovascular perspective. At age 16, evinacumab infused intravenously every 4 weeks was added to his treatment. After 12 months, his time-averaged LDL-C decreased by 53.4% from 8.75 mmol/L (338.4 mg/dL) to 4.08 mmol/L (157.8 mg/dL), despite reduced frequency of LDL apheresis from biweekly to monthly. He has experienced no adverse events. Overall, treatment has increased quality of life for him and his family. Evinacumab shows great promise for patients with HoFH, a difficult-to-treat and potentially life-threatening condition.

Lipoprotein(a) levels in children with homozygous familial hypercholesterolaemia: A cross-sectional study

Homozygous familial hypercholesterolaemia (HoFH) is a life-threatening disorder characterized by extremely elevated low-density lipoprotein cholesterol (LDL-C) levels. Untreated, severe atherosclerotic cardiovascular disease (ASCVD), including aortic valve stenosis (AVS), may already occur in childhood. Another important genetic risk factor for ASCVD and AVS is elevated lipoprotein(a) [Lp(a)], which is highly prevalent in the general paediatric population. However, data on Lp(a) in children with HoFH are scarce. Therefore, we performed a cross-sectional study to evaluate Lp(a) levels in children with HoFH and compared them to children with heterozygous FH (HeFH) and unaffected children. Adjusted least-square mean (95% CI) Lp(a) levels in HoFH (n=29), HeFH (n=101) and unaffected children (n=102) were 18.7 (12.0-29.1), 15.3 (11.8-19.8) and 10.5 (8.3-13.2) mg/dL, respectively (p-for-trend=0.007). Lp(a) levels in children with HoFH were higher than in children with HeFH and in unaffected children. Given the very high ASCVD risk with HoFH, identifying other risk factors such as elevated Lp(a) in these children is important. Therefore, Lp(a) levels should be measured at least once in all children with HoFH.

Pharmacotherapy in familial hypercholesterolemia - Current state and emerging paradigms

Familial hypercholesterolemia is a highly prevalent but underdiagnosed disease marked by increased risk of cardiovascular morbidity and mortality. Aggressive reduction of LDL-cholesterol is a hallmark of cardiovascular risk mitigation in familial hypercholesterolemia. More recently, we have witnessed an expanded repertoire of pharmacologic agents that directly target LDL-cholesterol and/or reduce heart disease burden. In this state-of-the-art review, we explore the development, clinical efficacy and limitations of existing and potential future therapeutics in familial hypercholesterolemia.

Updates in the management of pediatric dyslipidemia

PURPOSE OF REVIEW

Pediatric dyslipidemias increase the risk of atherosclerosis and clinical cardiovascular disease and are the leading cause of morbidity and mortality. Lifestyle modifications and pharmacotherapies have measurably improved abnormal lipids and reduced cardiovascular events. The review will focus on current standards of care and investigative medications with the potential to improve cardiovascular health in children and adults.

RECENT FINDINGS

Lifestyle interventions and statins remain cornerstones in the treatment of pediatric hyperlipidemias. Bile acid sequestrants and ezetimibe continue to be used in the pediatric population as well. In recent years, successful clinical trials have approved use of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors in children with familial hypercholesterolemia. Use of angiopoietin-like protein 3 (ANGPTL3) inhibitors is also promising as it causes marked improvement in low-density lipoprotein cholesterol with safe side effect profiles. Additional medications undergoing pediatric clinical trials include inclisiran, bempedoic acid, and lomitapide.

SUMMARY

Recent advances in pharmacotherapy, especially for treatment of familial hypercholesterolemia, greatly impact treatment of dyslipidemias in children. Despite the overall progress in the development of these medications, therapies targeted towards treating hypertriglyceridemia have lagged behind. Continuing research for the treatment of pediatric dyslipidemias remains an important endeavor to reduce the risk of atherosclerosis and future cardiovascular events in children.

How Genetic Variants in Children with Familial Hypercholesterolemia Not Only Guide Detection, but Also Treatment

Familial hypercholesterolemia (FH) is a hereditary disorder that causes severely elevated low-density lipoprotein (LDL-C) levels, which leads to an increased risk for premature cardiovascular disease. A variety of genetic variants can cause FH, namely variants in the genes for the LDL receptor (LDLR), apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and/or LDL-receptor adaptor protein 1 (LDLRAP1). Variants can exist in a heterozygous form (HeFH) or the more severe homozygous form (HoFH). If affected individuals are diagnosed early (through screening), they benefit tremendously from early initiation of lipid-lowering therapy, such as statins, and cardiovascular imaging to detect possible atherosclerosis. Over the last years, due to intensive research on the genetic basis of LDL-C metabolism, novel, promising therapies have been developed to reduce LDL-C levels and subsequently reduce cardiovascular risk. Results from studies on therapies focused on inhibiting PCSK9, a protein responsible for degradation of the LDLR, are impressive. As the effect of PCSK9 inhibitors (PCSK9-i) is dependent of residual LDLR activity, this medication is less potent in patients without functional LDLR (e.g., null/null variant). Novel therapies that are expected to become available in the near future focused on inhibition of another major regulatory protein in lipid metabolism (angiopoietin-like 3 (ANGPTL3)) might dramatically reduce the frequency of apheresis in children with HoFH, independently of their residual LDLR. At present, another independent risk factor for premature cardiovascular disease, elevated levels of lipoprotein(a) (Lp(a)), cannot be effectively treated with medication. Further understanding of the genetic basis of Lp(a) metabolism, however, offers a possibility for the development of novel therapies.

Hyperlipidemia and Cardiovascular Risk in Children and Adolescents

Atherosclerotic cardiovascular disease (ASCVD) represents the major cause of morbidity and mortality worldwide. The onset of the atherosclerosis process occurs during childhood and adolescence, subsequently leading to the onset of cardiovascular disease as young adults. Several cardiovascular risk factors can be identified in children and adolescents; however, hyperlipidemia, in conjunction with the global obesity epidemic, has emerged as the most prevalent, playing a key role in the development of ASCVD. Therefore, screening for hyperlipidemia is strongly recommended to detect high-risk children presenting with these disorders, as these patients deserve more intensive investigation and intervention. Treatment should be initiated as early as possible in order to reduce the risk of future ASCVD. In this review, we will discuss lipid metabolism and hyperlipidemia, focusing on correlations with cardiovascular risk and screening and therapeutic management to reduce or almost completely avoid the development of ASCVD.

Counseling couples at risk of having a child with homozygous familial hypercholesterolemia - Clinical experience and recommendations

Homozygous familial hypercholesterolemia (HoFH) is a rare, potentially life-limiting, inherited disorder of lipoprotein metabolism characterized by extremely high low-density lipoprotein cholesterol levels. When both parents have heterozygous FH, there is a 25% chance they will conceive a child with HoFH. Here we describe our clinical experience with two such prospective parent couples who were counseled regarding reproductive options and prenatal testing for HoFH. These cases showcase how, in consultation with a molecular geneticist and pediatric cardiologist, parents may be informed of the prognosis and treatment outlook of HoFH based on the FH-variants carried, to ultimately make personal decisions on reproductive options. One couple opted for prenatal testing and termination of pregnancy in case HoFH was found, while the other accepted the risk without testing. We review the available literature on preconception counseling for HoFH and provide practical guidance to clinicians counseling at-risk couples. Optimal counseling of prospective parents may help prevent future physical and psychological problems for both parent and child.

Severe Dyslipidemia Mimicking Familial Hypercholesterolemia Induced by High-Fat, Low-Carbohydrate Diets: A Critical Review

Emerging studies in the literature describe an association between high-fat, low-carbohydrate diets and severe hypercholesterolemia consistent with the levels observed in patients with (homozygous) familial hypercholesterolemia (FH). High levels of low-density lipoprotein cholesterol (LDL-C) may result from the reduced clearance of LDL particles from the circulation, the increased production of their precursor, or a combination of both. The increased intake of (saturated) fat and cholesterol, combined with limited to no intake of carbohydrates and fiber, are the main features of diets linked to hypercholesterolemia. However, several observations in previous studies, together with our observations from our lipid clinic, do not provide a definitive pathophysiological explanation for severe hypercholesterolemia. Therefore, we review these findings and possible pathophysiological explanations as well as opportunities for future research. Altogether, clinicians should rule out high-fat, low-carbohydrate diets as a possible cause for hypercholesterolemia in patients presenting with clinical FH in whom no mutation is found and discuss dietary modifications to durably reduce LDL-C levels and cardiovascular disease risk.

Genetic Heterogeneity of Familial Hypercholesterolemia: Repercussions for Molecular Diagnosis

Genetics of Familial Hypercholesterolemia (FH) is ascribable to pathogenic variants in genes encoding proteins leading to an impaired LDL uptake by the LDL receptor (LDLR). Two forms of the disease are possible, heterozygous (HeFH) and homozygous (HoFH), caused by one or two pathogenic variants, respectively, in the three main genes that are responsible for the autosomal dominant disease: LDLR, APOB and PCSK9 genes. The HeFH is the most common genetic disease in humans, being the prevalence about 1:300. Variants in the LDLRAP1 gene causes FH with a recessive inheritance and a specific APOE variant was described as causative of FH, contributing to increase FH genetic heterogeneity. In addition, variants in genes causing other dyslipidemias showing phenotypes overlapping with FH may mimic FH in patients without causative variants (FH-phenocopies; ABCG5, ABCG8, CYP27A1 and LIPA genes) or act as phenotype modifiers in patients with a pathogenic variant in a causative gene. The presence of several common variants was also considered a genetic basis of FH and several polygenic risk scores (PRS) have been described. The presence of a variant in modifier genes or high PRS in HeFH further exacerbates the phenotype, partially justifying its variability among patients. This review aims to report the updates on the genetic and molecular bases of FH with their implication for molecular diagnosis.

Management and clinical outcomes of patients with homozygous familial hypercholesteremia in Saudi Arabia

We report the incidence, patient characteristic with clinical outcomes in patients with homozygous familial hypercholesterolemia (HoFH) in Saudi Arabia. This is a retrospective and prospective, single center study which included 37 patients 14 years and older enrolled and followed up between 2018-2021 for three years. 46% were females, 78% were offspring of consanguineous marriage. LDLR mutation was in 78% and LDL-C/LDLRAP in 3% of patients. Mean LDL-C at the first presentation was 14.2±3.7 mmol/L, average Dutch lipid score was 20.9±6.24. LDL apheresis was performed on 70% of patients. Most patients were on ezetimibe (92%), high-dose statins ( 84%) and  PCSK9 inhibitors (32%). 48.6% had aortic stenosis, out of which 30% had severe aortic stenosis. Ten underwent aortic valve surgery (5 mechanical valve, 3 Ross procedure, 1 aortic valve repair, 1 bioprosthetic valve) and one had transcatheter aortic valve implantation (TAVI). Coronary artery bypass surgery (CABG) was performed on 32% and percutaneous intervention (PCI) on 11% of patients. HoFH patients have complex diseases with high morbidity and mortality, and benefit from a highly specialized multidisciplinary clinic to address their clinical needs. Although there are several therapeutic agents on the horizon, early diagnosis, and treatment of HoFH remain critical to optimize patient outcomes.

Genetic and molecular architecture of familial hypercholesterolemia

Atherosclerotic cardiovascular disease is the leading cause of death globally. Despite its important risk of premature atherosclerosis and cardiovascular disease, familial hypercholesterolemia (FH) is still largely underdiagnosed worldwide. It is one of the most frequently inherited diseases due to mutations, for autosomal dominant forms, in either of the LDLR, APOB, and PCSK9 genes or possibly a few mutations in the APOE gene and, for the rare autosomal forms, in the LDLRAP1 gene. The discovery of the genes implicated in the disease has largely helped to improve the diagnosis and treatment of FH from the LDLR by Brown and Goldstein, as well as the introduction of statins, to PCSK9 discovery in FH by Abifadel et al., and the very rapid availability of PCSK9 inhibitors. In the last two decades, major progress has been made in clinical and genetic diagnostic tools and the therapeutic arsenal against FH. Improving prevention, diagnosis, and treatment and making them more accessible to all patients will help reduce the lifelong burden of the disease.

Capacity of HDL to Efflux Cellular Cholesterol from Lipid-Loaded Macrophages Is Reduced in Patients with Familial Hypercholesterolemia

This study aimed to evaluate the high-density lipoprotein (HDL) capacity to efflux cellular cholesterol from lipid-loaded macrophages to find a reliable and low-cost biomarker with the purpose of better evaluating the risk of premature cardiovascular (CV) events in FH patients. This case-controlled study comprised 16 homozygous (HOFH) and 18 heterozygous (HEFH) FH patients, as well as 20 healthy subjects recruited as controls. Two main subfractions of HDL (HDL2 (d = 1.063-1.125 g/mL) and HDL3 (d = 1.125-1.210 g/mL)) were isolated from the patients' serum samples using sequential ultracentrifugation. After compositional characterization, the capacity of HDL to efflux cholesterol (CEC%) from lipid-laden macrophages was measured. The HDL2 and HDL3 subfractions showed some differences in lipid and protein composition between the studied groups. In addition, both HDL subfractions (p < 0.001) revealed significantly reduced CEC% in HOFH patients (HDL2: 2.5 ± 0.1 and HDL3: 3.2 ± 0.2) in comparison with the HEFH (HDL2: 3.2 ± 0.1% and HDL3: 4.1 ± 0.2%) and healthy (HDL2: 3.3 ± 0.2% and HDL3: 4.5 ± 0.3%) subjects. Additionally, multinomial logistic regression results indicated that the CEC% of both HDL2 (OR: 0.091; 95% CI: 0.018-0.452, p < 0.01) and HDL3 (OR: 0.118; 95% CI: 0.035-0.399, p < 0.01) subfractions are strongly and inversely associated with the homozygous form of FH. A decreased capacity of HDL particles to efflux cholesterol from macrophages might identify homozygous FH patients who are at elevated risk for premature CVDs. Prospective studies with a large sample size are warranted to evaluate this hypothesis.

Atherogenic Dyslipidemias: Unmet Needs and the Therapeutic Potential of Emerging and Novel Approaches and Drugs

Innovative lipid-modifying agents are valuable resources to improve the control of atherogenic dyslipidemias and reduce the lipid-related residual cardiovascular risk of patients with intolerance or who are not fully responsive to a consolidated standard of care (statins plus ezetimibe). Moreover, some of the upcoming compounds potently affect lipid targets that are thus far considered "unmodifiable". The present paper is a viewpoint aimed at presenting the incremental metabolic and cardiovascular benefits of the emerging lipid-modulating agents and real-life barriers, hindering their prescription by physicians and their assumption by patients, which need to be worked out for a more diffuse and appropriate drug utilization.

Atherosclerotic plaque regression in homozygous familial hypercholesterolaemia: a case report of a long-term lipid-lowering therapy involving LDL-receptor-independent mechanisms

Background

Homozygous familial hypercholesterolaemia (HoFH) is a rare and life-threatening genetic disease characterized by extremely elevated low-density lipoprotein cholesterol (LDL-C) levels, important xanthomatosis and increased risk of premature atherosclerotic cardiovascular disease. Management of HoFH at an early stage is recommended but conventional lipid-lowering therapies (LLTs) dependent on the LDL-receptor for clearance of LDL particles, are usually not sufficient. However, agents acting independently of the LDL-receptor, such as inhibitors of microsomal triglyceride transfer protein (MTP) or angiopoietin-like protein 3 (ANGPTL3), administered in combination, on top of standard-of-care LLT constitute a promising therapy for HoFH.

Case summary

The present case describes a long-term (>10 years) follow-up of a 52-year-old woman with severe HoFH, who was treated with conventional lipid-lowering medications (i.e. statins and ezetimibe) for several years before experiencing the risks and benefits that were encountered with the use of LDL-receptor-independent agents (MTP and ANGPTL3 inhibitors). This combination therapy demonstrated a good long-term safety and efficacy profile, while continuous monitoring of hepatic enzymes (sometimes requiring dose adjustments) and fat accumulation is recommended when using lomitapide.

Discussion

Treating this HoFH patient with an LLT involving the combination of MTP and ANGPTL3 LDL-receptor-independent inhibitors (lomitapide and evinacumab, respectively) showed remarkable improvement in LDL-C levels, disappearance of xanthomatosis and regression in atherosclerotic plaques. In addition to safety and efficacy, one should question the affordability and access hurdle that emerging combination of expensive therapies might constitute in the future for the payers. These challenges could eventually limit the clinical use of those innovative treatments despite their clinical benefit.

Metabolomic Approach to Screening Homozygotes in Chinese Patients with Severe Familial Hypercholesterolemia

Homozygous familial hypercholesterolemia (HoFH) is a rare inborn-errors-of-metabolism disorder characterized by devastatingly elevated low-density lipoprotein cholesterol (LDL-C) and premature cardiovascular disease. The gold standard for screening and diagnosing HoFH is genetic testing. In China, it is expensive and is always recommended for the most likely HoFH subjects with aggressive LDL-C phenotype. However, the LDL-C levels of HoFH patients and a substantial proportion of heterozygous FH (HeFH) patients overlapped considerably. Here, we performed a cost-effective metabolomic profiling on genetically diagnosed HoFH (n = 69) and HeFH patients (n = 101) with overlapping LDL-C levels, aiming to discovery a unique metabolic pattern for screening homozygotes in patients with severe FH. We demonstrated a differential serum metabolome profile in HoFH patients compared to HeFH patients. Twenty-one metabolomic alterations showed independent capability in differentiating HoFH from severe HeFH. The combined model based on seven identified metabolites yielded a corrected diagnosis in 91.3% of HoFH cases with an area under the curve value of 0.939. Collectively, this study demonstrated that metabolomic profiling serves as a useful and economical approach to preselecting homozygotes in FH patients with severe hypercholesterolemia and may help clinicians to conduct selective genetic confirmation testing and familial cascade screening.

Case report: Therapy adherence, MTTP variants, and course of atheroma in two patients with HoFH on low-dose, long-term lomitapide therapy

Background: Homozygous familial hypercholesterolemia (HoFH) is a rare and devastating genetic condition characterized by extremely elevated levels of low-density lipoprotein cholesterol (LDL-C) leading to an increased risk of premature atherosclerosis. Patients with Homozygous familial hypercholesterolemia mostly present with mutations in LDLR; however, herein, we present two cases with concomitant microsomal triglyceride transfer protein mutations, who showed different clinical courses and treatment adherence on long-term therapy with the new MTTP inhibitor lomitapide. Objectives: We aimed to present the possibility of preventing the progression of atherosclerotic burden with effective and safe LDL-C reduction in patients with Homozygous familial hypercholesterolemia on low-dose lomitapide therapy and emphasize the role of treatment adherence in therapy success. Methods: We present two patients with phenotypically Homozygous familial hypercholesterolemia, a compound heterozygous woman and a simple homozygous man, both with LDLR and additional MTTP mutations, who were treated with the MTTP-inhibiting agent lomitapide, with different treatment compliances. The role of impulsivity was investigated through Barratt Impulsivity Scale 11, and the extent of the atherosclerotic burden was followed up using coronary artery calcium scoring, echocardiographic and sonographic findings, and, eventually, through a strict follow-up of laboratory parameters. The patients were on lomitapide for 8 and 5 years, respectively, with no adverse effects. Conclusion: When accompanied by good adherence to therapy, low-dose lomitapide on top of standard lipid-lowering therapy with decreased frequency of lipid apheresis prevented the progression of atherosclerotic burden. Non-compliance might occur due to patient impulsivity and non-adherence to a low-fat diet.

An update on lipid apheresis for familial hypercholesterolemia

Familial hypercholesterolemia (FH) is an inherited metabolic defect leading to increased total cholesterol and low-density cholesterol (LDL) from birth onwards. Homozygous FH, presenting with clear clinical features, has a prevalence of ~ 1 per million. Prevalence of heterozygous FH is 1/500 European population. Atherosclerotic burden depends on the degree and duration of high LDL exposure. In severe cases, early detection is critical, and aggressive lipid-lowering therapies should begin in early childhood to reduce coronary heart disease risk. Pediatric therapeutic concepts correspond to adults and are orientated at LDL plasma concentration. Mean LDL plasma target value during treatment is < 135 mg/dL. Medication in childhood consists of ezetemibe, statins, resins, and PCSK-9 inhibitors, with consideration for age restrictions. Only a minority achieve the treatment target with drug therapy alone. Therapeutic apheresis for the treatment of hypercholesterolemia selectively removes lipoproteins from blood (lipid apheresis (LA)). LA has a long tradition in adult medicine and is also safely used in children by a variety of methods, if customized to special pediatric needs. LA reduces cholesterol levels independently of residual LDL-receptor function and not only achieves reduction or disappearance of xanthomas but also inhibits progression of or mitigates aortic valve stenosis and supravalvular aortic stenosis as well as coronary artery and other atherosclerotic lesions. Cardiovascular prognosis of patients with otherwise untreatable FH depends largely on timely use of LA. Taking into account LA as a lifelong treatment, starting early in childhood, it is important to accommodate therapy modalities, such as treatment frequency and point of time, into the life of the individual.

Evinacumab, an ANGPTL3 Inhibitor, in the Treatment of Dyslipidemia

Familial hypercholesterolemia (FH) is an inherited disorder. The level of low-density lipoprotein cholesterol (LDL-C) in patients with homozygous FH can be twice as high as that in patients with heterozygous FH. The inhibition of ANGPTL3 shows an important therapeutic approach in reducing LDL-C and triglycerides (TG) levels and, thus, is a potentially effective strategy in the treatment of FH. Evinacumab is a monoclonal antibody inhibiting circulating ANGPTL3, available under the trade name Evkeeza^® for the treatment of homozygous FH. It was reported that evinacumab is effective and safe in patients with homozygous and heterozygous FH, as well as resistant hypercholesterolemia and hypertriglyceridemia. This paper summarizes existing knowledge on the role of ANGPTL3, 4, and 8 proteins in lipoprotein metabolism, the findings from clinical trials with evinacumab, a fully human ANGPTL3 mAb, and the place for this new agent in lipid-lowering therapy.

Management of Familial Hypercholesterolemia with Special Emphasis on Evinacumab

Familial hypercholesterolemia (FH) is an underdiagnosed disease that contributes to a significant number of cardiovascular incidents through high serum Low-Density Lipoprotein Cholesterol (LDL-C) values. Its treatment primarily requires healthy lifestyle and therapy based on statins, ezetimibe and Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9); however, there are also new treatment options that can be used in patients who do not respond to therapy, among which we highlight evinacumab. Elevated LDL-C values, together with clinical manifestations associated with cholesterol deposition (e.g., tendon xanthomas, xanthelasma and arcus cornealis) and family history are the main elements in the diagnosis of FH. Pathognomonic signs of FH include extensor tendon xanthomas; however, their absence does not exclude the diagnosis. Elevated LDL-C levels lead to premature Atherosclerotic Cardiovascular Disease (ASCVD), which is why early diagnosis and treatment of FH is essential. Evinacumab, a novelty in pharmacological practice, having a complex mechanism of action, causes desirable changes in lipid parameters in patients with homozygous form of familial hypercholesterolemia (HoFH). This review collects and summarizes the most important aspects of the new drug, especially being a discovery in the treatment of HoFH, giving these patients hope for a longer and more comfortable life.

In Silico and In Vitro Analysis of Tacca Tubers (Tacca leontopetaloides) from Banyak Island, Aceh Singkil Regency, Indonesia, as Antihypercholesterolemia Agents

Tacca leontopetaloides (T. leontopetaloides) contain a number of active compounds such as flavonoids, tannins, phenolics, steroids, and alkaloids. The active compounds from plants have been shown to reduce the risk of cardiovascular disease by lowering cholesterol levels by inhibiting the enzyme 3-hydroxy-3-methylglutaryl-coenzym A (HMG-CoA) reductase activity. This study aims to investigate the potential active compounds in the ethanolic extract of Tacca tubers (T. leontopetaloides) from the Banyak Islands, Aceh Singkil Regency, Aceh Province both in vitro and in silico. Tacca tubers contain secondary metabolites including flavonoids, phenolics, tannins, steroids and saponins, according to phytochemical screening. In vitro investigation of ethanolic extract of Tacca tuber revealed inhibitory activity of HMG Co-A reductase with an IC₅₀ value of 4.92 ppm. Based on the in silico study, active compound from the extract, namely Stigmasterol with the highest binding affinities with HMG Co-A reductase (-7.2 kcal/mol). As a comparison, the inhibition of HMG Co-A reductase activity by simvastatin with an IC₅₀ 4.62 ppm and binding affinity -8.0 Kcal/mol. Our findings suggest that the ethanolic extract of Tacca tuber (T. leontopetaloides) from Banyak Islands, Aceh Province has the potential to inhibit the activity of HMG Co-A reductase.

Efficacy and Safety of Alirocumab in Children and Adolescents With Homozygous Familial Hypercholesterolemia: Phase 3, Multinational Open-Label Study

BACKGROUND

Despite progress in treating homozygous familial hypercholesterolemia, most patients do not achieve low-density lipoprotein cholesterol (LDL-C) targets. This study examined efficacy and safety of the PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor, alirocumab, in pediatric patients (aged 8-17 years) with inadequately controlled homozygous familial hypercholesterolemia.

METHODS

In this open-label, single-arm, multinational, Phase 3 study, patients (n=18) received alirocumab 75 mg or 150 mg (bodyweight <50 kg/≥50 kg) every 2 weeks as an adjunct to background treatment. The primary endpoint was percent change in LDL-C from baseline to Week 12. Secondary endpoints included changes in LDL-C and other lipid parameters up to 48 weeks, safety/tolerability, and alirocumab pharmacokinetics.

RESULTS

The mean age of patients was 12.4 years; 16/18 (89%) had mutations in the low-density lipoprotein receptor gene (LDLR) and 2/18 (11%) had mutations in the LDLR adapter protein 1 gene (LDLRAP1). At baseline, mean LDL-C (standard deviation) was 373.0 (193.5) mg/dL, which decreased by 4.1% at Week 12 (primary endpoint) and 11.4%, 13.2%, and 0.4% at Weeks 4, 24, and 48, respectively. At Week 12, 9/18 (50%) patients achieved LDL-C reductions ≥15%. Mean absolute LDL-C decreases ranged from 25 to 52 mg/dL over follow-up. A post hoc analysis demonstrated heterogeneity of responses according to genotype. There were no unexpected safety/tolerability findings. Free PCSK9 was reduced to near zero for all patients at Weeks 12 and 24.

CONCLUSIONS

The study supports the efficacy and safety of alirocumab as a potential adjunct to treatment for some pediatric patients with homozygous familial hypercholesterolemia.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; NCT03510715.

New algorithms for treating homozygous familial hypercholesterolemia

PURPOSE OF REVIEW

We reviewed current and future therapeutic options for patients with homozygous familial hypercholesterolemia (HoFH) and place this evidence in context of an adaptable treatment algorithm.

RECENT FINDINGS

Lowering LDL-C levels to normal in patients with HoFH is challenging, but a combination of multiple lipid-lowering therapies (LLT) is key. Patients with (near) absence of LDL receptor expression are most severely affected and frequently require regular lipoprotein apheresis on top of combined pharmacologic LLT. Therapies acting independently of the LDL receptor pathway, such as lomitapide and evinacumab, are considered game changers for many patients with HoFH, and may reduce the need for lipoprotein apheresis in future. Liver transplantation is to be considered a treatment option of last resort. Headway is being made in gene therapy strategies, either aiming to permanently replace or knock out key lipid-related genes, with first translational steps into humans being made. Cardiovascular disease risk management beyond LDL-C, such as residual Lp(a) or inflammatory risk, should be evaluated and addressed accordingly in HoFH.

SUMMARY

Hypercholesterolemia is notoriously difficult to control in most patients with HoFH, but multi-LLT, including newer drugs, allows reduction of LDL-C to levels unimaginable until a few years ago. Cost and availability of these new therapies are important future challenges to be addressed.

Complementary role of evinacumab in combination with lipoprotein apheresis in patients with homozygous familial hypercholesterolemia

Patients with homozygous familial hypercholesterolemia (FH) have severe hypercholesterolemia from birth and if untreated may experience very early onset of coronary artery disease in childhood or young adulthood with an aggressive course resulting in early death. Early initiation of aggressive low-density lipoprotein cholesterol (LDL-C) lowering is the mainstay of treatment, which requires the use of a multidrug treatment regimen, often in combination with lipoprotein apheresis, but LDL-C goal achievement is frequently unattainable due to the severity of baseline hypercholesterolemia and hyporesponsiveness to many LDL-C-lowering medications. Evinacumab, a monoclonal antibody that sequesters angiopoietin-like 3 protein and lowers LDL-C by an average of 49% in patients with homozygous FH, was approved by the Food and Drug Administration in February 2021 and is a major advance in treatment of these high-risk patients. In this report, we describe the complementary role of evinacumab in combination with lipoprotein apheresis in two patients with homozygous FH.

Cardiogenic shock following acute MI in a young patient with familial hypercholesterolemia, and severe aortic stenosis: A case report

Background

Familial hypercholesterolemia is a relatively rare disorder with various clinical manifestations including premature coronary artery disease.

Case presentation

A 15-year-old boy presented with acute exacerbation of dyspnea and exertional chest pain with a progressive feature since one month earlier. He had a clustered family history of premature cardiovascular death, hyperlipidemia, and cutaneous lesions in two of his siblings. He presented with acute severe heart failure accompanied with high levels of cardiac troponin and LDL cholesterol. Echocardiography revealed severe LV dysfunction, in concert with valvular and supravalvular Aortic stenosis. He underwent Coronary angiography, which showed involvement of Left main coronary artery and two-vessel disease. The patient was diagnosed with cardiogenic shock secondary to acute non-ST segment elevation myocardial infarction, and phenotype of familial hypercholesterolemia.

Conclusions

Premature malignant atherogenesis in both aortic root and coronary arteries with early presentation of acute myocardial infarction and severe heart failure is an uncommon constellation in early course of the FH, which leads to confined treatment options.

A familial hypercholesterolemia registry as the main tool for adequate management of the disease

Familial hypercholesterolemia (FH) is the most common, but poorly diagnosed autosomal-dominant genetic disease which increases the cardio-vascular risk.

AIM

To evaluate the experience of FH registry conducted in Karelia Republic.

METHODS

FH registry in Karelia is existing from 2004, it includes 350 patients with heterozygous FH (110 with definite FH), the mean age is 48 ± 2.3 years. The genetic study was performed in 102 patients (29.1%).

RESULT

The creation of the registry has contributed to the active identification of FH, and now the estimated frequency of FH occurrence in Karelia may be 1:300, in patients with cardiovascular disease 1:10. We also analyzed genetic features of FH in our republic and found that the LDL-C level, above which the probability of LDL receptor mutation increases in Karelia, is 6.5 mmol/L. We analyzed risk factors of ischemic heart disease and the prognosis in FH.

CONCLUSION

The creation and maintenance of a registry is an effective way of organizing timely diagnosis and adequate treatment of FH patients.

Familial Hypercholesterolemia Patients with COVID-19-Effective Cholesterol-Lowering Therapy is Urgent both during and after Infection

Heterozygous familial hypercholesterolemia (HeFH) patients are the prime example of subjects who are at high risk for both acute myocardial infarction (AMI) and ischemic stroke during, and post, SARS-CoV-2 infection. HeFH per se, if left untreated, results in premature clinical atherosclerosis often presenting in the fourth or fifth decade of life. The other concern in HeFH is endothelial dysfunction which is already evident from early childhood. In untreated HeFH patients, the severe hypercholesterolemia causes endothelial dysfunction from an early age, and as a result thereof, atherosclerotic lesions develop prematurely, particularly in the coronary arteries, and result in further endothelial dysfunction and inflammation in these critical segments of the arterial tree. As the pre-existing endothelial dysfunction in HeFH patients is most likely sensitive to further direct and indirect SARS-CoV-2 virus-dependent damage, we can infer that HeFH serves as an example of a comorbidity that predicts a poorer prognosis with COVID-19 infection. Indeed, a large US national database study showed that patients diagnosed with HeFH and SARS-CoV-2 infection had significantly increased Annualized Incidence Density Rates (AIDRs) of AMI when compared to matched HeFH controls not having been diagnosed with SARS-CoV-2 infection. Effective cholesterol lowering is essential for the prevention, or at least alleviation, of the detrimental effects of SARS-CoV-2 infection among HeFH patients. Due to the pre-existing subclinical or even clinical atherosclerotic cardiovascular disease in subjects with HeFH, cholesterol-lowering treatment needs to be continued or, better still, intensified during, and for an extended period post, SARS-CoV-2 infection.

Risk factors, clinical features, and outcomes of premature acute myocardial infarction

AIMS

To investigate the risk factors, clinical features, and prognostic factors of patients with premature acute myocardial infarction (AMI).

MATERIALS AND METHODS

A retrospective cohort study of patients with AMI included in data from the West China Hospital of Sichuan University from 2011 to 2019 was divided into premature AMI (aged < 55 years in men and < 65 years in women) and non-premature AMI. Patients' demographics, laboratory tests, Electrocardiography (ECG), cardiac ultrasound, and coronary angiography reports were collected. All-cause death after incident premature MI was enumerated as the primary endpoint.

RESULTS

Among all 8,942 AMI cases, 2,513 were premature AMI (79.8% men). Compared to the non-premature AMI group, risk factors such as smoking, dyslipidemia, overweight, obesity, and a family history of coronary heart disease (CHD) were more prevalent in the premature AMI group. The cumulative survival rate of patients in the premature AMI group was significantly better than the non-premature AMI group during a mean follow-up of 4.6 years (HR = 0.27, 95% CI 0.22-0.32, p < 0.001). Low left ventricular ejection fraction (LVEF) (Adjusted HR 3.00, 95% CI 1.85-4.88, P < 0.001), peak N-terminal pro-B-type natriuretic peptide (NT-proBNP) level (Adjusted HR 1.34, 95% CI 1.18-1.52, P < 0.001) and the occurrence of in-hospital major adverse cardiovascular and cerebrovascular events (MACCEs) (Adjusted HR 2.36, 95% CI 1.45-3.85, P = 0.001) were predictors of poor prognosis in premature AMI patients.

CONCLUSION

AMI in young patients is associated with unhealthy lifestyles such as smoking, dyslipidemia, and obesity. Low LVEF, elevated NT-proBNP peak level, and the occurrence of in-hospital MACCEs were predictors of poor prognosis in premature AMI patients.

Long-Term Efficacy and Safety of Evinacumab in Patients with Homozygous Familial Hypercholesterolemia: Real-World Clinical Experience

Homozygous familial hypercholesterolemia (HoFH) is a rare, genetic condition characterized by markedly elevated plasma low-density lipoprotein cholesterol (LDL-C) concentrations from birth and increased risk of premature atherosclerotic cardiovascular disease. Evinacumab is an inhibitor of angiopoietin-like 3 protein that offers a new approach for correcting high LDL-C in HoFH. Evinacumab was administered intravenously (15 mg/kg Q4W) for 24 months in 7 patients with genetically confirmed HoFH, receiving background lipoprotein apheresis (LA) and/or lipid-lowering treatment (LLT). Assessment of efficacy and safety were carried out before and after 24 months of evinacumab treatment. The LDL-C lowering effect of evinacumab without LA were also investigated in the 7 HoFH patients after a subsequent compassionate extension period. Twenty-four months of treatment with evinacumab against background LA and LLT resulted in a significant reduction in LDL-C (−46.8%; p < 0.001). LDL-C reduction with evinacumab was maintained during the compassionate extensions period in the absence of treatment with LA (−43.4%; mean follow-up of 208 ± 90 days). Evinacumab was well-tolerated, with no major adverse event reported or significant changes in liver and muscle enzyme concentrations. Our findings suggest that evinacumab is a safe and effective treatment for patients with HoFH receiving best standard of care in a routine setting.

New Trends and Therapies for Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is associated with an elevated risk of atherosclerosis. The finding of monogenic defects indicates higher atherosclerotic risk in comparison with hypercholesterolemia of other etiologies. However, in heterozygous FH, cardiovascular risk is heterogeneous and depends not only on high cholesterol levels but also on the presence of other biomarkers and genes. The development of atherosclerosis risk scores specific for heterozygous FH and the use of subclinical coronary atherosclerosis imaging help with identifying higher-risk individuals who may benefit from further cholesterol lowering with PCSK9 inhibitors. There is no question about the extreme high risk in homozygous FH, and intensive LDL-cholesterol-lowering therapy must be started as soon as possible. These patients have gained life free of events in comparison with the past, but a high atherosclerosis residual risk persists. Furthermore, there is also the issue of aortic and supra-aortic valve disease development. Newer therapies such as inhibitors of microsomal transfer protein and angiopoietin-like protein 3 have opened the possibility of LDL-cholesterol normalization in homozygous FH and may provide an alternative to lipoprotein apheresis for these patients. Gene-based therapies may provide more definite solutions for lowering high LDL cholesterol and consequent atherosclerosis risk for people with FH.

PCSK9 Inhibitor Wars: How Does Inclisiran Fit in with Current Monoclonal Antibody Inhibitor Therapy? Considerations for Patient Selection

PURPOSE OF REVIEW

Treatment of dyslipidemia represents one of the most crucial strategies to reduce risk of atherosclerotic cardiovascular (CV) disease (ASCVD). In this review, we critically summarize our knowledge on emerging cholesterol-lowering therapy, targeting PCSK9, paying particular attention on treatment allocation of two drug groups, currently available for clinical use, namely, anti-PCSK9 monoclonal antibodies (mAbs) and inclisiran, a first-in-class small interfering RNA against PCSK9.

RECENT FINDINGS

Although both drug classes show a pronounced, but fairly similar reduction in LDL-cholesterol, their long-term safety is still unknown. Compared to mAbs, inclisiran has a more favorable dosing regimen with biannual application that might improve therapeutic adherence significantly. However, a CV outcome trial (CVOT) for inclisiran is still missing. If inclisiran will be safe and effective in ongoing/future CVOTs, it has a huge potential to overcome medication non-compliance, thereby providing a powerful therapeutic option to decrease the burden of ASCVD.

Screening and Management of Dyslipidemia in Children and Adolescents

This review provides an overview of pediatric dyslipidemia emphasizing screening and treatment recommendations. The presence of risk factors for cardiovascular disease in childhood poses significant risk for the development of atherosclerotic cardiovascular disease and cardiovascular events in adulthood. While atherogenic dyslipidemia is the most common dyslipidemia seen in children and can be suspected based on the presence of risk factors (such as obesity), familial hypercholesterolemia can be found in children with no risk factors. As such, universal cholesterol screening is recommended to identify children with these disorders in order to initiate treatment and reduce the risk of future cardiovascular disease. Treatment of pediatric dyslipidemia begins with lifestyle modifications, but primary genetic dyslipidemias may require medications such as statins. As pediatric lipid disorders often have genetic or familial components, it is important that all physicians are aware that cardiovascular risk begins in childhood, and can both identify these disorders in pediatric patients and counsel their adult patients with dyslipidemia to have their children screened.