Familial Hypercholesterolemia—Epidemiology, Diagnosis, and Screening

Does Genotype Affect the Efficacy of PCSK9 Inhibitors in the Treatment of Familial Hypercholesterolemia?

PURPOSE OF REVIEW

This review discusses whether patients' genotype affects the efficacy of PCSK9 inhibitors in treating familial hypercholesterolemia and how this might influence clinical management.

RECENT FINDINGS

Currently, available evidence consistently demonstrates and is in good agreement that, in general, the LDL-C-lowering effect of PCSK9 inhibitors is similar across genotypes, except for compound heterozygous and homozygous familial hypercholesterolemia (FH). However, it remains to be seen whether the comparable therapeutic effect in lowering LDL-C level also leads to a comparable degree of cardiovascular risk reduction with different genotypes. Generally, the level of LDL-C reduction following PCSK9 inhibitor treatment is similar within different genotypes. Hence, genotype is a less reliable predictor for further LDL-C level reduction on PCSK9 inhibitor therapy, and attention should be given to other external influences, especially for heterozygous FH.

Safety and efficacy of antisense oligonucleotides on triglyceride, apolipoprotein C-III, and other lipid parameters levels in hypertriglyceridemia; a network meta-analysis of randomized controlled trials

BACKGROUND

Hypertriglyceridemia is an independent risk factor for cardiovascular diseases. In previous trials, apolipoprotein C-III (APOC3) inhibition through the antisense oligonucleotides volanesorsen, olezarsen, and plozasiran reduced triglyceride levels. However, the three medications' safety and efficacy have yet to be compared.

METHODS

A network meta-analysis was performed to compare multiple doses of the three medications to each other through the placebo. Randomized controlled trials (RCTs) were retrieved by searching PubMed, EMBASE, Web of Science, SCOPUS, and Cochrane until November 22nd, 2024. The mean difference (MD) and 95% confidence interval (CI) were used for continuous outcomes. The risk ratio (RR) and 95% CI were used for dichotomous outcomes.

RESULTS

Ten RCTs with a total of 1,129 patients were included. volanesorsen 300 mg once weekly showed the most significant percent reduction in triglyceride levels (MD = -91.0%, 95% CI: (-109.2%; -72.8%); P < 0.01). Only plozasiran once monthly, regardless of the dose, showed a non-significant percent reduction in triglycerides. This finding should be taken cautiously as the data were derived from a phase 1 trial with a small sample size. All the regimens significantly reduced APOC3 levels compared to placebo, with plozasiran 100 mg monthly and volanesorsen 300 mg once weekly showing the most significant reduction (MD range: -92.8% to -88.5%; P < 0.01). None of the treatments showed a statistically significant difference in overall adverse events rate compared to the placebo.

CONCLUSION

APOC3 antisense oligonucleotide inhibitors effectively reduced triglyceride and APOC3 levels in hypertriglyceridemia with an acceptable safety profile. However, the results should be interpreted cautiously due to the small sample size. Further research is needed to confirm the beneficial effects of APOC3 inhibitors and show strong evidence of the impact of each regimen.

Lowering LDL cholesterol by PCSK9 inhibition: a new era of gene silencing, RNA, and alternative therapies

Proprotein convertase subtilisin/kexin type 9 (PCSK9) discovery has added a new paradigm to our understanding of cholesterol homeostasis and lipid metabolism. Since its discovery, PCSK9 inhibitors have become a widely investigated therapeutic class for lipid management in cardiovascular diseases and hypercholesterolemia. Scientists have explored different approaches for PCSK9 inhibition, such as monoclonal antibodies (mAbs), gene silencing and gene editing techniques, vaccines, mimetic peptides, and small molecules. European Medicines Agency (EMA) and United States Food and Drug Administration (US FDA) have approved only three PCSK9 inhibitors, including two monoclonal antibodies and one small interfering ribonucleic acid (siRNA). Despite the efficacy of approved large molecules, high costs and the need for regular injection have limited their adherence to the patient. This review aims to provide an understanding of PCSK9's function in Low-Density Lipoprotein Cholesterol (LDL-C) management, its current treatment, recent advancements, and potential future development of small molecules in the class of PCSK9 inhibitors.

Clinical reality and challenges with familial hypercholesterolemia patients' management. 2024 results from the Regional Center for Rare Diseases (RCRD) Registry in Poland

BACKGROUND

Despite advancements in early diagnosis and effective medications in last decade, most heterozygous familial hypercholesterolemia (heFH) patients still fail to achieve their low-density lipoprotein cholesterol (LDL-C) goals and remain at residual cardiovascular disease risk. We present recent data from the regional FH registry in Poland, highlighting the challenges and real-life clinical management of FH patients.

METHODS

The registry is held at the Regional Centre for Rare Diseases, founded in 2016, at the 2nd largest, supraregional hospital in Poland, where >80 different rare diseases in patients from all over Poland are diagnosed and treated, including phenotypically or genetically diagnosed FH patients. Our analysis focused on both children and adult FH patients, excluding those treated with inclisiran due to a small sample size (n = 5).

RESULTS

We studied 173 consecutive heFH patients, median age for adult population was 40 years (range: 27-57), of whom 56.14 % were women. Among the population, 82.1 % were adults (n = 142), and 31 were children (17.92 %; median age 9 (8-13), females 58.16 %). Children exhibited lower total cholesterol and triglyceride levels compared to adults, with no significant differences in LDL-C and high-density lipoprotein cholesterol (HDL-C) levels. Molecular diagnosis in the whole population revealed that 76.6 % had an LDL receptor (LDLR) mutation, while 23.4 % had an apolipoprotein B (APOB) mutation. Risk assessment categorized patients into high (70.7 %), very high (22.1 %), and extremely high (7.1 %) risk groups. Triple therapy achieved treatment goals in 61.76 % of adults and 70.97 % of children. At baseline, 36.62 % of adult patients were not using statins. High-intensity statin therapy combined with ezetimibe was initiated for the remaining patients. Only 3.33 % of patients avoided statins due to complete intolerance. Ezetimibe was used in 57.27 % of patients (mostly in combination therapy), and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors were prescribed for 28.17 % FH patients. In adults receiving statin and ezetimibe therapy, median achieved LDL-C was 141 mg/dl (107-184). For triple therapy, median achieved LDL-C was 52.5 mg/dL (32-86.5). Overall median achieved LDL-C in the study population was 99.5 mg/dl (57.5-145.4). PCSK9 inhibitors reduced LDL-C by 165.6 mg/dl. Combination therapy did not significantly alter baseline lipoprotein(a) (Lp(a)) levels (p = 0.134), and PCSK9 inhibitors led to a mean Lp(a) reduction of 18.66 mg/dl (45 % reduction; p = 0.013). Multivariable regression analysis identified key factors for achieving LDL-C targets in FH patients: DLCN total score, DLCN category, ezetimibe use, and PCSK9 inhibitors.

CONCLUSIONS

In Poland, FH patients are often diagnosed too late (usually over 40 years of age), and many still do not reach their LDL-C goals. Combination LLT double or triple therapy significantly increases the likelihood of achieving LDL-C targets - even up to fivefold. Therefore, unrestricted access to PCSK9 inhibitors for all FH patients is crucial, without the current limitations imposed by drug reimbursement programs like B101.

Efficacy of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors in Patients with Heterozygous Familial Hypercholesterolemia: A Meta-analysis

BACKGROUND

Patients with heterozygous familial hypercholesterolemia (HeFH) are at high risk of major adverse cardiovascular events (MACE) and mortality. Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i), including monoclonal antibodies (alirocumab, evolocumab) and small interfering RNA (inclisiran), substantially reduce lipid levels. This meta-analysis aimed to evaluate the efficacy of both types of PCSK9i specifically in patients with HeFH.

METHODS

A librarian-assisted systematic search of MEDLINE, Embase, CENTRAL, and ClinicalTrials.gov was performed from 2013 to 2023. Randomized controlled trials of PCSK9i versus control in patients with HeFH were included. No language restrictions were applied. Cochrane Risk-of-Bias tool 2 was used to assess quality of evidence. Meta-analyses were performed using Cochrane ReviewManager. Outcomes included change in atherogenic lipids, MACE, and all-cause death.

RESULTS

Seven trials were included (N = 2196). Overall risk of bias was mostly low or with some concerns. Median follow-up was 24 weeks. PCSK9i had an uncertain effect on MACE (odds ratio [OR] 1.25, 95% confidence interval [CI] 0.69-2.26) and all-cause death (OR 2.47, 95% CI 0.33-18.26) due to the low event rate and short follow-up. However, PCSK9i significantly reduced low-density lipoprotein cholesterol (LDL-C) by 54% (95% CI 49-58), apolipoprotein B by 43% (95% CI 37-49), and lipoprotein(a) by 20% (95% CI 13-28).

CONCLUSIONS

In patients with HeFH, PCSK9i significantly reduced atherogenic lipids (LDL-C, apolipoprotein B, and lipoprotein[a]). Despite this, the effect on MACE or all-cause death was unclear. Larger-scale randomized controlled trials of longer duration are needed to validate whether this short-term reduction in lipid levels translates into a reduction in clinically meaningful outcomes.

Causal relationships of familial hypercholesterolemia with the risk of multiple vitamin deficiencies: a Mendelian randomization study

Background

The causal relationship between familial hypercholesterolemia (FH) and various vitamin deficiencies has not yet been elucidated. Therefore, this study investigated the cause-and-effect relationship between FH and the risk of multiple vitamin deficiencies in humans.

Methods

Mendelian randomization (MR) analysis was performed by extracting six datasets for FH, FH with ischemic heart disease (IHD), and vitamin deficiency (vitamin A, thiamine, other B-group vitamins, and vitamin D) from the FinnGen study, covering a total of 329,115; 316,290; 354,932; 354,949; 355,411 and 355,238 individuals, respectively.

Results

FH was suggestively associated with higher odds of thiamine deficiency [inverse variance weighted odds ratio (ORIVW) 95% confidence interval (CI): 1.62 (1.03, 2.55), P = 0.036] and vitamin D deficiencies [ORIVW CI: 1.35 (1.04, 1.75), P = 0.024], low-density lipoprotein receptor (LDLR) rs112898275 variant, rs11591147 and rs499883 in proprotein convertase subtilisin/kexin 9 (PCSK9), rs9644862 in cyclin-dependent kinase inhibitor 2 B antisense RNA1 (CDKN2B-AS1), and rs142834163 in dedicator of cytokinesis 6 (DOCK6) and rs115478735 in ABO blood group (ABO) strongly influenced the risk of thiamine deficiency, while the rs7412 variant in apolipoprotein E (APOE) mostly influenced the risk of vitamin D deficiency. FH with IHD was suggestively associated with higher odds of vitamin D deficiency (ORIVW, weighted median [WM][95%CI]: 1.31 [1.05, 1.64]; 1.47 [1.10, 1.97]) (P = 0.018; 0.010) without any single significant SNPs observed.

Conclusion

FH was positively associated with increased risks of thiamine and vitamin D deficiencies, revealing a prospective and unfortunate complication of FH.

Effect of diet and genotype on the lipidome of mice with altered lipoprotein metabolism

The present study describes and compares the impact of PCSK9 and LDLR, two pivotal players in cholesterol metabolism, on the whole lipidome of plasma, liver and aorta in different dietary conditions. This issue is relevant, since several lipid species, circulating at very low concentrations, have the ability to impair lipid metabolism and promote atherosclerosis development. To this aim, wild-type, hypercholesterolemic Ldlr-KO, and hypocholesterolemic Pcsk9-KO mice were fed a standard chow or a Western-type diet up to 30 and 16 weeks of age, respectively. 42 lipids including cholesterol, cholesteryl esters, several sphingolipids, phospholipids, and lysophospholipids, accumulated uniquely in the atherosclerotic aorta of Western-type diet-fed Ldlr-KO mice. In addition, multiple organ/tissue comparisons allowed us to identify 16 lipids whose plasma and hepatic patterns mirrored the lipidome of the atherosclerotic aorta. These lipid species, belonging to cholesteryl esters, glucosyl/galactosylceramide, lactosylceramide, globotriaosylceramide, sphingomyelin, and phosphatidylcholine could be further investigated as circulating biomarkers or therapeutic targets.

Analysis of low-density lipoprotein receptor gene mutations in a family with familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH) is a common monogenic autosomal dominant disorder, primarily mainly caused by pathogenic mutations in the low-density lipoprotein receptor (LDLR) gene. Through phenotypic-genetic linkage analysis, two LDLR pathogenic mutations were identified in FH families: c.G1027A (p.Gly343Ser) and c.G1879A (p.Ala627Thr).

MATERIALS AND METHODS

Whole exome sequencing was conducted on the proband with familial hypercholesterolemia to identify the target gene and screen for potential pathogenic mutations. The suspicious responsible mutation sites in 14 family members were analyzed using Sanger sequencing to assess genotype-phenotype correlations. Mutant and wild type plasmids were constructed and transfected into HEK293T cells to evaluate LDLR mRNA and protein expression. In parallel, bioinformatics tools were employed to predict structural and functional changes in the mutant LDLR.

RESULTS

Immunofluorescence analysis revealed no significant difference in the intracellular localization of the p.Gly343Ser mutation, whereas protein expression of the p.Ala627Thr mutation was decreased and predominantly localized in the cytoplasm. Western blotting has showed that protein expression levels of the mutant variants were markedly declined in both cell lysates and supernatants. Enzyme linked immunosorbent assay has demonstrated that LDLR protein levels in the supernatant of cell culture medium was not significant different from those of the wild-type group. However, LDLR protein levels in the cell lysate of both the Gly343Ser and Ala627Thr variants groups were significantly lower than those in the wild-type group. Bioinformatic predictions further suggested that these mutations may affect post-translational modifications of the protein, providing additional insight into the mechanisms underlying the observed reduction in protein expression.

CONCLUSIONS

In this study, we identified two heterozygous pathogenic variants in the LDLR gene, c.G1027A (p.Gly343Ser) and c.G1879A (p.Ala627Thr), in a family with familial hypercholesterolemia. We also conducted preliminary investigations into the mechanisms by which these mutations contribute to disease pathology.

The Impact of Convertase Subtilisin/Kexin Type 9 Monoclonal Antibodies with and without Apheresis on Platelet Aggregation in Familial Hypercholesterolemia

BACKGROUND AND AIMS

It is well known that elevated cholesterol is associated with enhanced platelet aggregation and patients suffering from familial hypercholesterolemia (FH) have a high risk of thrombotic cardiovascular events. Although decreasing cholesterol level is associated with attenuation of platelet hyperactivity, there are currently no data on the effect of convertase subtilisin/kexin type 9 monoclonal antibodies (PCSK9ab) on platelet reactivity in FH. The aim of the study was to analyse the impact of different therapies including PCSK9ab on platelet aggregation in FH.

METHODS

This study enrolled all 15 patients treated in the University Hospital Hradec Králové for FH. PCSK9ab have been administered in 12 of 15 patients while 8 patients were also undergoing lipid apheresis. Blood samples from all patients including pre- and post-apheresis period were tested for platelet aggregation triggered by 7 inducers, and the effect of 3 clinically used drugs (acetylsalicylic acid, ticagrelor and vorapaxar) was compared as well.

RESULTS

Although apheresis decreased the reactivity of platelets in general, platelet responses were not different between non-apheresis patients treated with PCSK9ab and apheresis patients (post-apheresis values) with the exception of ristocetin. However, when compared to age-matched healthy population, FH patients had significantly lower platelet aggregation responses to 4 out of 7 used inducers and higher profit from 2 out of 3 used antiplatelet drugs even after exclusion of FH patients regularly receiving conventional antiplatelet treatment.

CONCLUSION

This study showed for the first time the suitability of PCSK9ab treatment for reduction of platelet reactivity in FH patients.

Lipidomic profiling in patients with familial hypercholesterolemia: Abnormalities in glycerolipids and oxysterols

OBJECTIVES AND AIM

This study aimed to identify precise biomarkers and develop targeted therapeutic strategies for preventing premature atherosclerotic cardiovascular disease in patients with familial hypercholesterolemia (FH) by investigating the quantitative and qualitative abnormalities in the metabolic network of lipids in these patients using an advanced lipidomics platform.

DESIGN & METHODS

The study population comprised 18 homozygous (HoFH), 18 heterozygous (HeFH) FH patients, and 20 healthy controls. Cholesterol oxidation products (oxysterol, COPs) and main lipid classes were determined using gas chromatography-mass spectrometry. Results were expressed as percentages of total fat matter for lipid classes and percentages of total COPs for oxysterols. The principal component analysis (PCA) was also carried out, to highlight the correlation between studied parameters and groups investigated.

RESULTS

Patients (both HoFH and HeFH) showed lower content of free fatty acids (FFAs) and greater values of triacylglycerols (TAGs) in comparison to controls. HoFH showed lower monoacylglycerols (P<0.01) and higher free cholesterol (FC) (P<0.05) when compared to HeFH and controls. The total content of COPs ranged from 1.96 to 4.25 mg/dL, from 2.27 to 4.05 mg/dL, and from 0.79 to 4.12 mg/dL in healthy controls, HoFH and HeFH groups, respectively, with no significant differences between patients and controls. In general, the 7α-hydroxycholesterol (7α-HC) was greater than other COPs. However, no significant differences were found between the three studied groups. Moreover, an opposite trend was observed between 7α-HC and 7-ketocholesterol (7-KC). Additionally, when PCA was carried out, the first two PCs explained 92.13 % of the total variance, of which the PC1 describes 53.94 % of variance mainly correlated to TAGs, diacylglycerols (DAGs), and 7-KC. On the other hand, the PC2 was correlated primarily for FFAs, FC and esterified sterols (E-STE).

CONCLUSIONS

In conclusion, abnormal levels of TAGs, DAGs and 7-KC were associated with HeFH while HoFH was associated with the abnormal amount of E-STE.

Pediatric Pharmacology for the Primary Care Provider: Advances and Limitations

Despite >1 in 5 children taking prescription drugs in the United States, off-label drug use is common. To increase the study of drugs in children, regulatory bodies have enacted legislation to incentivize and require pediatric drug studies. As a result of this legislation, novel trial approaches, and an increase in personnel with pediatric expertise, there have been numerous advancements in pediatric drug development. With this review, we aim to highlight developments in pediatric pharmacology over the past 6 years for the most common disease processes that may be treated pharmacologically by the pediatric primary care provider. Using information extracted from label changes between 2018 and 2023, the published literature, and Clinicaltrials.gov, we discuss advances across multiple therapeutic areas relevant to the pediatric primary care provider, including asthma, obesity and related disorders, mental health disorders, infections, and dermatologic conditions. We highlight instances in which new drugs have been developed on the basis of a deeper mechanistic understanding of illness and instances in which labels have been expanded in older drugs on the basis of newly available data. We then consider additional factors that affect pediatric drug use, including cost and nonpharmacologic therapies. Although there is work to be done, efforts focused on pediatric-specific drug development will increase the availability of evidence-based, labeled guidance for commonly prescribed drugs and improve outcomes through the safe and effective use of drugs in children.

Algorithm for detection and screening of familial hypercholesterolemia in Lithuanian population

BACKGROUND

Familial hypercholesterolemia (FH) is one of the most common autosomal dominant diseases. FH causes a lifelong increase in low-density lipoprotein cholesterol (LDL-C) levels, which in turn leads to atherosclerotic cardiovascular disease. The incidence of FH is widely underestimated and undertreated, despite the availability and effectiveness of lipid-lowering therapy. Patients with FH have an increased cardiovascular risk; therefore, early diagnosis and treatment are vital. To address the burden of FH, several countries have implemented national FH screening programmes. The currently used method for FH detection in Lithuania is mainly based on opportunistic testing with subsequent cascade screening of index cases' first-degree relatives.

METHODS

A total of 428 patients were included in this study. Patients with suspected FH are referred to a lipidology center for thorough evaluation. Patients who met the criteria for probable or definite FH according to the Dutch Lipid Clinic Network (DLCN) scoring system and/or had LDL-C > = 6.5 mmol/l were subjected to genetic testing. Laboratory and instrumental tests, vascular marker data of early atherosclerosis, and consultations by other specialists, such as radiologists and ophthalmologists, were also recorded.

RESULTS

A total of 127/428 (30%) patients were genetically tested. FH-related mutations were found in 38.6% (n = 49/127) of the patients. Coronary artery disease (CAD) was diagnosed in 13% (n = 57/428) of the included patients, whereas premature CAD was found in 47/428 (11%) patients. CAD was diagnosed in 19% (n = 9/49) of patients with FH-related mutations, and this diagnosis was premature for all of them.

CONCLUSIONS

Most patients in this study were classified as probable or possible FH without difference of age and sex. The median age of FH diagnosis was 47 years with significantly older females than males, which refers to the strong interface of this study with the LitHir programme. CAD and premature CAD were more common among patients with probable and definite FH, as well as those with an FH-causing mutation. The algorithm described in this study is the first attempt in Lithuania to implement a specific tool which allows to maximise FH detection rates, establish an accurate diagnosis of FH, excluding secondary causes of dyslipidaemia, and to select patients for cascade screening initiation more precisely.

Cost-Effectiveness of Screening Strategies for Familial Hypercholesterolaemia: An Updated Systematic Review

BACKGROUND

OBJECTIVE: This study aimed to systematically synthesise the cost-effectiveness of screening strategies to detect heterozygous familial hypercholesterolemia (FH).

METHODS

We searched seven databases from inception to 2 February , 2023, for eligible cost-effective analysis (CEA) that evaluated screening strategies for FH versus the standard care for FH detection. Independent reviewers performed the screening, data extraction and quality evaluation. Cost results were adapted to 2022 US dollars (US$) to facilitate comparisons between studies using the same screening strategies. Cost-effectiveness thresholds were based on the original study criteria.

RESULTS

A total of 21 studies evaluating 62 strategies were included in this review, most of the studies (95%) adopted a healthcare perspective in the base case, and majority were set in high-income countries. Strategies analysed included cascade screening (23 strategies), opportunistic screening (13 strategies), systematic screening (11 strategies) and population-wide screening (15 strategies). Most of the strategies relied on genetic diagnosis for case ascertainment. The most common comparator was no screening, but some studies compared the proposed strategy versus current screening strategies or versus the best next alternative. Six studies evaluated screening in children while the remaining were targeted at adults. From a healthcare perspective, cascade screening was cost-effective in 78% of the studies [cost-adapted incremental cost-effectiveness ratios (ICERs) ranged from dominant to 2022 US$ 104,877], opportunistic screening in 85% (ICERs from US$4959 to US$41,705), systematic screening in 80% (ICERs from US$2763 to US$69,969) and population-wide screening in 60% (ICERs from US$1484 to US$223,240). The most common driver of ICER identified in the sensitivity analysis was the long-term cost of lipid-lowering treatment.

CONCLUSIONS

Based on reported willingness to pay thresholds for each setting, most CEA studies concluded that screening for FH compared with no screening was cost-effective, regardless of the screening strategy. Cascade screening resulted in the largest health benefits per person tested.

Transient second-degree type 2 atrioventricular block after infliximab infusion in a patient with Crohn's disease and heterozygous familial hypercholesterolemia

Current treatments for patients in the active phase of Crohn's disease (CD) include conventional treatments and biological treatments. Infliximab (IFX), a TNF-α antagonist, is recommended to induce remission in patients with moderate-to-severe CD who have not responded to conventional therapy. IFX terminates the inflammatory cascade by inhibiting the nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), and caspase signaling pathways and increases the apoptosis of activated T cells in inflamed tissues.

High Prevalence of Familial Hypercholesterolemia Due to the Founder Effect of the LDLR c.2271del Variant in Communities of Oaxaca, Mexico

INTRODUCTION

In Mexico, familial hypercholesterolemia (FH) is underdiagnosed, but population screening in small communities where at least one homozygous patient has already been detected results in a useful and inexpensive approach to reduce this problem. Considering that we previously reported nine homozygous cases from the state of Oaxaca, we decided to perform a population screening to identify patients with FH and to describe both their biochemical and genetic characteristics.

METHODS

LDL cholesterol (LDLc) was quantified in 2,093 individuals from 11 communities in Oaxaca; either adults with LDLc levels ≥170 mg/dL or children with LDLc ≥130 mg/dL were classified as suggestive of FH and therefore included in the genetic study. LDLR and APOB (547bp fragment of exon 26) genes were screened by sequencing and MLPA analysis.

RESULTS

Two hundred and five individuals had suggestive FH, with a mean LDLc of 223 ± 54 mg/dL (range: 131-383 mg/dL). Two pathogenic variants in the LDLR gene were detected in 149 individuals: c.-139_-130del (n = 1) and c.2271del (n = 148). All patients had a heterozygous genotype. With the cascade screening of their relatives (n = 177), 15 heterozygous individuals for the c.2271del variant were identified, presenting a mean LDLc of 133 ± 35 mg/dL (range: 60-168 mg/dL).

CONCLUSIONS

The FH frequency in this study was 7.8% (164/2093), the highest reported worldwide. A founder effect combined with inbreeding could be responsible for the high percentage of patients with the LDLR c.2271del variant (99.4%), which allowed us to detect both significant biochemical heterogeneity and incomplete penetrance; hence, we assumed the presence of phenotype-modifying variants.

Failure of lipid control by PCSK9 inhibitors in compound heterozygous familial hypercholesterolemia complicated with premature myocardial infarction: A case report

Key Clinical Message

A certain level of low-density lipoprotein receptor activity is crucial for the efficacy of PCSK9i. Therapeutic strategies for familial hypercholesterolemia patients should consider drug efficacy, and genetic testing will be helpful.

Abstract

Familial hypercholesterolemia (FH) is a serious autosomal dominant disorder. Managing blood lipids in FH patients poses greater challenges for clinicians. Drug therapy may not always yield satisfactory results, particularly in individuals with low-density lipoprotein receptor (LDLR) negative mutations. Herein, we report a young female harboring an LDLR frameshift mutation. This patient developed xanthomas at 7 months old and underwent several years of treatment involving four classes of lipid-lowering drugs, including PCSK9i. However, the response to drug therapy was limited in this patient and eventually culminated in premature myocardial infarction. The efficacy of PCSK9i depends on the activity of LDLR. The inefficacy of PCSK9i may arise from the extensive mutations which leading to loss of LDLR activity. Therapy plans for these patients should take into account the efficacy of drug therapy. Early genetic testing is crucial for clinicians to make informed decisions regarding therapy options.

Establishing non-fasting reference values for plasma lipids levels based on age, sex, and puberty stage in a French-Canadian pediatric population

BACKGROUND

Dyslipidemias, including familial hypercholesterolemia (FH), are a significant risk factor for cardiovascular diseases. FH is a genetic disorder resulting in elevated levels of low-density lipoprotein cholesterol (LDL-C) and an increased probability of early cardiovascular disorders. Heterozygous familial hypercholesterolemia (HeFH) is the most common form, affecting approximately 1 in 250 individuals worldwide, with a higher prevalence among the French-Canadian population. Childhood is a critical period for screening risk factors, but the recommendation for non-fasting screening remains controversial due to a lack of specific reference values for this state. This study aims to establish reference values for lipid levels in non-fasting children from Sherbrooke, Quebec, Canada, that will be specific for sex, age, and pubertal stages.

METHODS

Blood samples and corresponding anthropometric data were collected from 356 healthy children aged from 6 to 13. They were categorized either into two age groups: Cohort 6-8 and Cohort 9-13, or into pubertal stages. Reference values, specifically the 2.5th, 5th, 10th, 50th, 90th, 95th, and 97.5th percentiles were determined using the CLSI C28-A3 guidelines.

RESULTS

Lipid profiles did not significantly differ between sexes, except for higher levels of high-density lipoprotein (HDL-C) in boys within Cohort 6-8. HDL-C levels significantly increased, while LDL-C and non-HDL-C levels significantly decreased in both sexes with age. Non-fasting age- and pubertal stages-specific reference values were established.

CONCLUSION

This study established reference intervals for lipid markers in non-fasting state within the pediatric French-Canadian population. These findings could be used in dyslipidemia screening in daily practice.

Targeting systemic inflammation in metabolic disorders. A therapeutic candidate for the prevention of cardiovascular diseases?

Cardiovascular disease (CVD) remains the leading cause of death and disability worldwide. While many factors can contribute to CVD, atherosclerosis is the cardinal underlying pathology, and its development is associated with several metabolic risk factors including dyslipidemia and obesity. Recent studies have definitively demonstrated a link between low-grade systemic inflammation and two relevant metabolic abnormalities: hypercholesterolemia and obesity. Interestingly, both metabolic disorders are also associated with endothelial dysfunction/activation, a proinflammatory and prothrombotic phenotype of the endothelium that involves leukocyte infiltration into the arterial wall, one of the earliest stages of atherogenesis. This article reviews the current literature on the intricate relationship between hypercholesterolemia and obesity and the associated systemic inflammation and endothelial dysfunction, and discusses the effectiveness of present, emerging and in-development pharmacological therapies used to treat these metabolic disorders with a focus on their effects on the associated systemic inflammatory state and cardiovascular risk.

Refinement of the diagnostic approach for the identification of children and adolescents affected by familial hypercholesterolemia: Evidence from the LIPIGEN study

BACKGROUND AND AIMS

We aimed to describe the limitations of familiar hypercholesterolemia (FH) diagnosis in childhood based on the presence of the typical features of FH, such as physical sings of cholesterol accumulation and personal or family history of premature cardiovascular disease or hypercholesterolemia, comparing their prevalence in the adult and paediatric FH population, and to illustrate how additional information can lead to a more effective diagnosis of FH at a younger age.

METHODS

From the Italian LIPIGEN cohort, we selected 1188 (≥18 years) and 708 (<18 years) genetically-confirmed heterozygous FH, with no missing personal FH features. The prevalence of personal and familial FH features was compared between the two groups. For a sub-group of the paediatric cohort (N = 374), data about premature coronary heart disease (CHD) in second-degree family members were also included in the evaluation.

RESULTS

The lower prevalence of typical FH features in children/adolescents vs adults was confirmed: the prevalence of tendon xanthoma was 2.1% vs 13.1%, and arcus cornealis was present in 1.6% vs 11.2% of the cohorts, respectively. No children presented clinical history of premature CHD or cerebral/peripheral vascular disease compared to 8.8% and 5.6% of adults, respectively. The prevalence of premature CHD in first-degree relatives was significantly higher in adults compared to children/adolescents (38.9% vs 19.7%). In the sub-cohort analysis, a premature CHD event in parents was reported in 63 out of 374 subjects (16.8%), but the percentage increased to 54.0% extending the evaluation also to second-degree relatives.

CONCLUSIONS

In children, the typical FH features are clearly less informative than in adults. A more thorough data collection, adding information about second-degree relatives, could improve the diagnosis of FH at younger age.

Screening and verifying the mutations in the LDLR and APOB genes in a Chinese family with familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH) is an autosomal dominant genetic disorder. The primary objective of this study was to identify the major pathogenic mutations in a Chinese family with FH.

METHODS

Whole-genome sequencing (WGS) was used to identify variants of FH-related genes, including low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin 9 (PCSK9). Bioinformatics software was used to predict signal peptides, transmembrane structures, and spatial construction information of the mutated sequences. Western blotting was performed on the mutant protein to determine the presence of the major structural domains of the LDLR. The PCSK9 and APOB genes were screened and analyzed. Moreover, the proband and his brother were treated with a PCSK9 inhibitor for 1 year, and the effect of the treatment on lipid levels was assessed.

RESULTS

WGS revealed two potentially pathogenic mutations in the LDLR gene. One was a novel mutation, c.497delinsGGATCCCCCAGCTGCATCCCCCAG (p. Ala166fs), and the other was a known pathogenic mutation, c.2054C>T (p. Pro685Leu). Bioinformatics prediction and in vitro experiments revealed that the novel mutation could not be expressed on the cell membrane. Numerous gene variants were identified in the APOB gene that may have a significant impact on the family members with FH. Thus, it is suggested that the severe manifestation of FH in the proband primarily resulted from the cumulative genetic effects of variants in both LDLR and APOB. However, a subsequent study indicated that treatment with a PCSK9 inhibitor (Evolocumab) did not significantly reduce the blood lipid levels in the proband or his brother.

CONCLUSIONS

The cumulative effect of LDLR and APOB variants was the primary cause of elevated blood lipid levels in this family. However, PCSK9 inhibitor therapy did not appear to be beneficial for the proband. This study emphasizes the importance of genetic testing in determining the most suitable treatment options for patients with FH.

Prevalence of familial hypercholesterolemia and its association with coronary artery disease: A Chinese cohort study

Background

Familial hypercholesterolemia (FH) is underrecognized, and its association with coronary artery disease (CAD) remains limited, especially in China. We aimed to investigate the prevalence of FH and its relationship with CAD in a large Chinese cohort.

Methods

FH was defined using the Make Early Diagnosis to Prevent Early Death (MEDPED) criteria. The crude and age-sex standardized prevalence of FH were calculated based on surveys of the Prediction for Atherosclerotic Cardiovascular Disease Risk in China (China-PAR) project during 2007-2008. The associations of FH with incident CAD and its major subtypes were estimated with the cohort-stratified multivariate Cox proportional hazard models based on the data from the baseline to the last follow-up (2018-2020).

Results

Among 98,885 included participants, 190 participants were defined as FH. Crude and age-sex standardized prevalence and 95% confidence interval (CI) of FH were 0.19% (0.17%-0.22%) and 0.13% (0.10%-0.16%), respectively. The prevalence varied across age groups and peaked in the group of 60-<70 years (0.28%), and the peak prevalence (0.18%) in males was earlier, yet lower than the peak crude prevalence in females (0.41%). During a mean follow-up of 10.7 years, 2493 cases of incident CAD were identified. After multivariate adjustment, FH patients had a 2.03-fold greater risk of developing CAD compared to non-FH participants.

Conclusions

The prevalence of FH was estimated to be 0.19% in the participants, and it was associated with an elevated risk of incident CAD. Our study suggests that early screening of FH has certain public health significance for the prevention of CAD.

The Association of Thyroid-Stimulating Hormone (TSH) Levels and Lipid Profile in Euthyroid Patients with Familial Hypercholesterolemia

Previous studies reported a relationship between thyroid-stimulating hormone (TSH) and low-density lipoprotein cholesterol (LDL-C) levels. In this study, we aim to evaluate the impact of TSH levels on lipid profile in patients with familial hypercholesterolemia (FH) and euthyroid state. Patients were selected from the Isfahan FH registry. The Dutch Lipid Clinic Network (DLCN) criteria are used to detect FH. Patients were classified into no FH, possible FH, probable FH, and definite FH groups based on the DLCN scores. Patients with any cause of secondary hyperlipidemia, including hypothyroidism, were excluded from this study. The study group consisted of 103 patients with possible FH, 25 patients with definite FH, and 63 individuals with no FH. The mean TSH and LDL-C levels among participants were 2.10 ± 1.22 mU/l and 142.17 ± 62.56 mg/dl, respectively. No positive or negative correlation was found between serum TSH and total cholesterol (P value = 0.438), high-density lipoprotein cholesterol (P = 0.225), triglycerides (P value = 0.863), and LDL-C (P value = 0.203). We found no correlation between serum TSH levels and lipid profiles in euthyroid patients with FH.

Different clinical phenotypes of a pair of siblings with familial hypercholesterolemia: a case report and literature review

BACKGROUND

Familial hypercholesterolemia (FH) leads to high plasma low-density lipoprotein cholesterol (LDL-C) levels and early cardiovascular morbidity and mortality. We treated a pair of siblings with FH. The cardiovascular manifestations in the proband were more severe than those in his elder sister, although they had almost similar LDL-C levels, ages, and lifestyles. Herein, we report the cases of this family to explore the possible causes of clinical phenotypic differences within the same genetic background.

CASE PRESENTATION

We treated a 27-year-old male patient and his 30-year-old sister, both with FH. The coronary angiogram in the male patient revealed 80, 70, and 100% stenosis of the initial, distal right coronary artery branch, and left anterior descending branch, respectively, whereas his sister had almost no coronary stenosis. We treated them accordingly and performed family screening. We found that the LDL-C/particle discordance of the proband is much greater than that of his elder sister. In addition, the average size of LDL-C particle in the proband was smaller than that in his sister.

CONCLUSIONS

Patients with FH have a much higher risk of premature atherosclerotic cardiovascular disease, but the clinical manifestations are heterogeneous. The smaller LDL particle size may be the underlying cause for different clinical outcomes in this pair of FH cases and be a potential novel indicator for predicting the prognosis of FH.

Inclisiran-A Revolutionary Addition to a Cholesterol-Lowering Therapy

Hypercholesterolemia plays a crucial role in the development of atherosclerosis, but it remains an undertreated and underdiagnosed disease. Taking into consideration the high prevalence of lipid disorders, long duration of the asymptomatic course of the disease, life-threatening complications resulting from inaccurate therapy, and stringent treatment goals concerning LDL cholesterol level in the prevention of cardiovascular events, novel lipid-lowering therapies have been introduced in the last few years. In this article, a drug belonging to the group of small interfering RNA (siRNA) called inclisiran is described. It is a novel molecule that increases the number of LDL receptors (LDLRs) on the surface of hepatic cells by preventing the formation of proprotein convertase subtilisin/kexin type 9 (PCSK9) responsible for the degradation of LDLRs. With great potential for lowering plasma LDL cholesterol level, high liver specificity, comfortable dosing regimen, and good tolerance without significant adverse effects, it could play an important part in future hypolipemic therapies.

Association of triglyceride-glucose index with atherosclerotic cardiovascular disease and mortality among familial hypercholesterolemia patients

BACKGROUND

Familial hypercholesterolemia (FH) is an inherited metabolic disorder with a high level of low-density lipoprotein cholesterol and the worse prognosis. The triglyceride-glucose (TyG) index, an emerging tool to reflect insulin resistance (IR), is positively associated with a higher risk of atherosclerotic cardiovascular disease (ASCVD) in healthy individuals, but the value of TyG index has never been evaluated in FH patients. This study aimed to determine the association between the TyG index and glucose metabolic indicators, insulin resistance (IR) status, the risk of ASCVD and mortality among FH patients.

METHODS

Data from National Health and Nutrition Examination Survey (NHANES) 1999-2018 were utilized. 941 FH individuals with TyG index information were included and categorized into three groups: < 8.5, 8.5-9.0, and > 9.0. Spearman correlation analysis was used to test the association of TyG index and various established glucose metabolism-related indicators. Logistic and Cox regression analysis were used to assess the association of TyG index with ASCVD and mortality. The possible nonlinear relationships between TyG index and the all-cause or cardiovascular death were further evaluated on a continuous scale with restricted cubic spline (RCS) curves.

RESULTS

TyG index was positively associated with fasting glucose, HbA1c, fasting insulin and the homeostatic model assessment of insulin resistance (HOMA-IR) index (all p < 0.001). The risk of ASCVD increased by 74% with every 1 unit increase of TyG index (95%CI: 1.15-2.63, p = 0.01). During the median 114-month follow-up, 151 all-cause death and 57 cardiovascular death were recorded. Strong U/J-shaped relations were observed according to the RCS results (p = 0.0083 and 0.0046 for all-cause and cardiovascular death). A higher TyG index was independently associated with both all-cause death and cardiovascular death. Results remained similar among FH patients with IR (HOMA-IR ≥ 2.69). Moreover, addition of TyG index showed helpful discrimination of both survival from all-cause death and cardiovascular death (p < 0.05).

CONCLUSION

TyG index was applicable to reflect glucose metabolism status in FH adults, and a high TyG index was an independent risk factor of both ASCVD and mortality.

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.

Assessing the genetic burden of familial hypercholesterolemia in a large middle eastern biobank

BACKGROUND

The genetic architecture underlying Familial Hypercholesterolemia (FH) in Middle Eastern Arabs is yet to be fully described, and approaches to assess this from population-wide biobanks are important for public health planning and personalized medicine.

METHODS

We evaluate the pilot phase cohort (n = 6,140 adults) of the Qatar Biobank (QBB) for FH using the Dutch Lipid Clinic Network (DLCN) criteria, followed by an in-depth characterization of all genetic alleles in known dominant (LDLR, APOB, and PCSK9) and recessive (LDLRAP1, ABCG5, ABCG8, and LIPA) FH-causing genes derived from whole-genome sequencing (WGS). We also investigate the utility of a globally established 12-SNP polygenic risk score to predict FH individuals in this cohort with Arab ancestry.

RESULTS

Using DLCN criteria, we identify eight (0.1%) 'definite', 41 (0.7%) 'probable' and 334 (5.4%) 'possible' FH individuals, estimating a prevalence of 'definite or probable' FH in the Qatari cohort of ~ 1:125. We identify ten previously known pathogenic single-nucleotide variants (SNVs) and 14 putatively novel SNVs, as well as one novel copy number variant in PCSK9. Further, despite the modest sample size, we identify one homozygote for a known pathogenic variant (ABCG8, p. Gly574Arg, global MAF = 4.49E-05) associated with Sitosterolemia 2. Finally, calculation of polygenic risk scores found that individuals with 'definite or probable' FH have a significantly higher LDL-C SNP score than 'unlikely' individuals (p = 0.0003), demonstrating its utility in Arab populations.

CONCLUSION

We design and implement a standardized approach to phenotyping a population biobank for FH risk followed by systematically identifying known variants and assessing putative novel variants contributing to FH burden in Qatar. Our results motivate similar studies in population-level biobanks - especially those with globally under-represented ancestries - and highlight the importance of genetic screening programs for early detection and management of individuals with high FH risk in health systems.

Leveraging knowledge of HDLs major protein ApoA1: Structure, function, mutations, and potential therapeutics

Apolipoprotein A1 (ApoA1) is a member of the Apolipoprotein family of proteins. It's a vital protein that helps in the production of high-density lipoprotein (HDL) particles, which are crucial for reverse cholesterol transport (RCT). It also has anti-inflammatory, anti-atherogenic, anti-apoptotic, and anti-thrombotic properties. These functions interact to give HDL particles their cardioprotective characteristics. ApoA1 has recently been investigated for its potential role in atherosclerosis, diabetes, neurological diseases, cancer, and certain infectious diseases. Since ApoA1's discovery, numerous mutations have been reported that affect its structural integrity and alter its function. Hence these insights have led to the development of clinically relevant peptides and synthetic reconstituted HDL (rHDL) that mimics the function of ApoA1. As a result, this review has aimed to provide an organized explanation of our understanding of the ApoA1 protein structure and its role in various essential pathways. Furthermore, we have comprehensively reviewed the important ApoA1 mutations (24 mutations) that are reported to be involved in various diseases. Finally, we've focused on the therapeutic potentials of some of the beneficial mutations, small peptides, and synthetic rHDL that are currently being researched or developed, since these will aid in the development of novel therapeutics in the future.

Exploring the Efficacy of Alirocumab and Evolocumab in Reducing Low-Density Lipoprotein (LDL) Cholesterol Levels in Patients With Familial Hypercholesterolemia: A Systematic Review

Patients with familial hypercholesterolemia (FH) have an increased risk of having abnormally high low-density lipoprotein cholesterol (LDL-C) levels. One of the main groups of drugs used for FH is statins. However, even with statins, most patients with FH do not achieve their pre-defined therapeutic LDL-C goals. Therefore, proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) serve to decrease LDL-C levels in that population. A total of 838 articles were found after searching the databases of PubMed, MEDLINE, and Cochrane Library. After including only full-text peer-reviewed articles published in the last 10 years, 67 articles remained. Thirteen articles were put through the Cochrane bias assessment tool to screen for bias. After a strict quality assessment based on the criteria, eight articles were extracted and included in this systematic review. The data extraction from these studies showed that alirocumab and evolocumab were efficacious in decreasing LDL-C levels and achieving the pre-defined LDL-C goals. Many parameters influenced the strength of the LDL-C reduction: sample size of the population, genetic structure of the patients affected by FH, length of the trial, or baseline lipid-lowering therapy used. Therefore, one must consider several other factors while evaluating the percent reduction of PCSK9i. This review is limited because it did not comment on these drugs' cardiovascular outcomes or mortality benefits. In addition, some of the articles used in this systematic review have small sample sizes and short trial times, limiting the long-term evaluation of these drugs.

A scoping review of interventions increasing screening and diagnosis of familial hypercholesterolemia

PURPOSE

Familial hypercholesterolemia (FH) is one of the most common genetic conditions, with a prevalence of approximately 1 in 250 individuals. If left untreated, FH greatly increases risk for cardiovascular disease and premature death. Currently, FH is largely underdiagnosed and interventions are needed to increase identification. The purpose of this study was to identify effective interventions aimed at increasing FH diagnosis.

METHODS

A scoping review of the literature addressing interventions to increase FH detection was conducted. Included studies detailed interventions that increased screening and detection of FH globally. Studies were characterized by intervention type and analyzed for themes using the Consolidated Framework for Implementation Research.

RESULTS

A total of 46 studies across 32 countries were included in the review. All studies were effective in increasing FH detection. In total, 12 different intervention types were extracted with the most used being cascade and electronic medical record screening-based interventions.

CONCLUSION

Given the diversity of effective interventions identified in this review, future efforts could explore approaches that maximize identification through a combination of interventions. Our results support one such strategy that uses electronic medical records to screen for index cases and a 2-step indirect and direct contact method of index cases' relatives.

The Prevalence and Genetic Spectrum of Familial Hypercholesterolemia in Qatar Based on Whole Genome Sequencing of 14,000 Subjects

Familial hypercholesterolemia (FH) is an inherited disease characterized by reduced efficiency of low-density lipoprotein-cholesterol (LDL-C) removal from the blood and, consequently, an increased risk of life-threatening early cardiovascular complications. In Qatar, the prevalence of FH has not been determined and the disease, as in many countries, is largely underdiagnosed. In this study, we combined whole-genome sequencing data from the Qatar Genome Program with deep phenotype data from Qatar Biobank for 14,056 subjects to determine the genetic spectrum and estimate the prevalence of FH in Qatar. We used the Dutch Lipid Clinic Network (DLCN) as a diagnostic tool and scrutinized 11 FH-related genes for known pathogenic and possibly pathogenic mutations. Results revealed an estimated prevalence of 0.8% (1:125) for definite/probable cases of FH in the Qatari population. We detected 16 known pathogenic/likely pathogenic mutations in LDLR and one in PCSK9; all in a heterozygous state with high penetrance. The most common mutation was rs1064793799 (c.313+3A >C) followed by rs771019366 (p.Asp90Gly); both in LDLR. In addition, we identified 18 highly penetrant possibly pathogenic variants, of which 5 were Qatari-specific, in LDLR, APOB, PCSK9 and APOE, which are predicted to be among the top 1% most deleterious mutations in the human genome but further validations are required to confirm their pathogenicity. We did not detect any homozygous FH or autosomal recessive mutations in our study cohort. This pioneering study provides a reliable estimate of FH prevalence in Qatar based on a significantly large population-based cohort, whilst uncovering the spectrum of genetic variants associated with FH.

Should We Be Screening for Ischaemic Heart Disease Earlier in Childhood?

Ischaemic heart disease is the most common cause of death in males and the second in the female gender. Yet we often only focus on identification and treatment of this foremost cause of death in adulthood. The review asks the question what form of coronary disease do we encounter in childhood, what predisposing factors give rise to atherosclerosis and what strategies in childhood could we employ to detect and reduce atherosclerosis development in later life.

Polygenic risk score for hypercholesterolemia in a Brazilian familial hypercholesterolemia cohort

Background and aims

Familial hypercholesterolemia (FH) is a genetic disorder characterized by high levels of LDL-C leading to premature cardiovascular disease (CAD). Only about 40% of individuals with a clinical diagnosis of FH have a causative genetic variant identified, and a proportion of genetically negative cases may have a polygenic cause rather than a still unidentified monogenic cause. This work aims to evaluate and validate the role of a polygenic risk score (PRS) associated with hypercholesterolemia in a Brazilian FH cohort and its clinical implications.

Methods

We analyzed a previously derived PRS of 12 and 6 SNPs (Single Nucleotide Polymorphism) in 684 FH individuals (491 mutation-negative [FH/M-], 193 mutation-positive [FH/M+]) and in 1605 controls. Coronary artery calcium (CAC) score was also evaluated.

Results

The PRS was independently associated with LDL-C in control individuals (p < 0.001). Within this group, in individuals in the highest quartile of the 12 SNPs PRS, the odds ratio for CAC score >100 was 1.7 (95% CI: 1.01-2.88, p = 0.04) after adjustment for age and sex. Subjects in the FH/M- group had the highest mean score in both 12 and 6 SNPs PRS (38.25 and 27.82, respectively) when compared to the other two groups (p = 2.2 × 10-16). Both scores were also higher in the FH/M+ group (36.48 and 26.26, respectively) when compared to the control group (p < 0.001 for the two scores) but inferior to the FH/M- group. Within FH individuals, the presence of a higher PRS score was not associated with LDL-C levels or with CAD risk.

Conclusion

A higher PRS is associated with significantly higher levels of LDL-C and it is independently associated with higher CAC in the Brazilian general population. A polygenic cause can explain a fraction of FH/M- individuals but does not appear to be a modulator of the clinical phenotype among FH individuals, regardless of mutation status.

The promising novel therapies for familial hypercholesterolemia

Background

The incidence of premature atherosclerotic cardiovascular disease in familial hypercholesterolemia (FH) is high. In recent years, novel therapeutic modalities have shown significant lipid‐lowering ability. In this paper, we summarize the recent developments in novel therapies for FH via the treatment of different targets and discuss the characteristics of each targeted therapy. Based on the process of protein synthesis, we attempt to summarize the direct‐effect targets including protein, RNA, and DNA.

Methods

For this systematic review, relevant studies are assessed by searching in several databases including PubMed, Web of Science, Scopus, and Google Scholar. The publications of original researches are considered for screening.

Results

Most drugs are protein‐targeted such as molecule‐based and monoclonal antibodies, including statins, ezetimibe, alirocumab, evolocumab, and evinacumab. Both antisense oligonucleotide (ASO) and small interfering RNA (siRNA) approaches, such as mipomersen, vupanorsen, inclisiran, and ARO‐ANG3, are designed to reduce the number of mRNA transcripts and then degrade proteins. DNA‐targeted therapies such as adeno‐associated virus or CRISPR–Cas9 modification could be used to deliver or edit genes to address a genetic deficiency and improve the related phenotype.

Conclusion

While the therapies based on different targets including protein, RNA, and DNA are on different stages of development, the mechanisms of these novel therapies may provide new ideas for precision medicine.

Ten things to know about ten cardiovascular disease risk factors - 2022

The American Society for Preventive Cardiology (ASPC) "Ten things to know about ten cardiovascular disease risk factors - 2022" is a summary document regarding cardiovascular disease (CVD) risk factors. This 2022 update provides summary tables of ten things to know about 10 CVD risk factors and builds upon the foundation of prior annual versions of "Ten things to know about ten cardiovascular disease risk factors" published since 2020. This 2022 version provides the perspective of ASPC members and includes updated sentinel references (i.e., applicable guidelines and select reviews) for each CVD risk factor section. The ten CVD risk factors include unhealthful dietary intake, physical inactivity, dyslipidemia, pre-diabetes/diabetes, high blood pressure, obesity, considerations of select populations (older age, race/ethnicity, and sex differences), thrombosis (with smoking as a potential contributor to thrombosis), kidney dysfunction and genetics/familial hypercholesterolemia. Other CVD risk factors may be relevant, beyond the CVD risk factors discussed here. However, it is the intent of the ASPC "Ten things to know about ten cardiovascular disease risk factors - 2022" to provide a tabular overview of things to know about ten of the most common CVD risk factors applicable to preventive cardiology and provide ready access to applicable guidelines and sentinel reviews.

Retinal Microvascular Changes in Familial Hypercholesterolemia: Analysis with Swept-Source Optical Coherence Tomography Angiography

Familial hypercholesterolemia (FH) is a common but underdiagnosed genetic disorder affecting cholesterol metabolism, leading to atherosclerotic disease. The relationship between retinal microvascular changes and the presence of atheroma in patients with FH (FH group), and in comparison to volunteers without FH (CT group), needs further investigation. This cross-sectional study was conducted in a university hospital between October 1, 2020 and May 31, 2021. Cardiovascular data, including the Coronary Artery Calcium (CAC) score, were recorded for FH patients. Macula angiograms were acquired using swept-source optical coherence tomography angiography (SS OCT-A) to analyze both the superficial capillary plexus (SCP) and deep capillary plexus (DCP). A total of 162 eyes of 83 patients were enrolled in the FH group and 121 eyes of 78 volunteers in the CT group. A statistically significant association was found between the CAC score and both vessel density (β = −0.002 [95% CI, −0.004; −0.0005], p = 0.010) and vessel length (β = −0.00005 [95% CI, −0.00008; −0.00001], p = 0.010) in the DCP. The FH group had a significantly lower foveal avascular zone circularity index than the CT group in multivariate analysis (0.67 ± 0.16 in the FH group vs. 0.72 ± 0.10 in the CT group, β = 0.04 [95% CI, 0.002; 0.07], p = 0.037). Retinal microvascularization is altered in FH and retinal vascular densities are modified according to the CAC score.

A Very Rare Variant in SREBF2, a Possible Cause of Hypercholesterolemia and Increased Glycemic Levels

Patients with high cholesterol and glucose levels are at high risk for cardiovascular disease. The Sterol Regulatory Element Binding Protein (SREBP) system regulates genes involved in lipid, cholesterol and glucose pathways. Autosomal Dominant Hypercholesterolemias (ADHs) are a group of diseases with increased cholesterol levels. They affect 1 out of every 500 individuals. About 20-30% of patients do not present any mutation in the known genes (LDLR, APOB and PCSK9). ADHs constitute a good model to identify the genes involved in the alteration of lipid levels or possible therapeutic targets. In this paper, we studied whether a mutation in the SREBP system could be responsible for ADH and other metabolic alterations present in these patients. Forty-one ADH patients without mutations in the main responsible genes were screened by direct sequencing of SREBP system genes. A luciferase reporter assay of the found mutation and an oral glucose tolerance test in carriers and non-carriers were performed. We found a novel mutation in the SREBF2 gene that increases transcription levels and cosegregates with hypercholesterolemia, and we found increased glucose levels in one family. SREBP2 is known to be involved in cholesterol synthesis, plasma levels and glucose metabolism in humans. The found mutation may involve the SREBF2 gene in hypercholesterolemia combined with hyperglycemia.

Hyperlipidemia patients carrying LDLR splicing mutation c.1187-2A>G respond favorably to rosuvastatin and PCSK9 inhibitor evolocumab

Mutations in the LDL receptor gene LDLR cause familial hypercholesterolemia (FH); however, the pharmacogenomics of specific LDLR mutations remains poorly understood. The goals of this study were to identify the genetic cause of a three-generation Chinese family affected with autosomal dominant FH, and to investigate the response of FH patients in the family to statin and evolocumab. Whole exome sequencing of the FH family with four patients and six unaffected members identified a heterozygous splicing mutation (c.1187-2A>G) in LDLR. The mutation co-segregated with FH in the family, providing strong genetic evidence to support its pathogenicity. The proband was a 48-year-old male FH patient who had an acute myocardial infarction (MI) and ventricular fibrillation (VF), and showed LDL-C of 5.23 mmol/L. A combination of life style modifications on food and exercise and treatment with rosuvastatin reduced his LDL-C to 2.05-2.80 mmol/L. Addition of ezetimibe did not improve rosuvastatin therapy, but addition of evolocumab further reduced LDL-C by 70% to 0.7 mmol/L at the first time and by 67% to 1.31 mmol/L at the second time. Rosuvastatin also reduced LDL-C for proband's father and sister by 40% and 43-63%, respectively. Lovastatin alone or addition to rosuvastatin treatment did not have any effect on LDL-C for the proband and his son. Both patients carry ApoE 3/4 genotype and SLCO1B1 rs4149056 TT genotype. These results suggest that combined treatment with rosuvastatin (but not lovastatin or ezetimibe) and evolocumab can control LDL-C to meet the LDL-C treatment goal for patients with LDLR splicing mutation c.1187-2A>G.

Genetically Engineered Hamster Models of Dyslipidemia and Atherosclerosis

Animal models of human diseases play an extremely important role in biomedical research. Among them, mice are widely used animal models for translational research, especially because of ease of generation of genetically engineered mice. However, because of the great differences in biology between mice and humans, translation of findings to humans remains a major issue. Therefore, the exploration of models with biological and metabolic characteristics closer to those of humans has never stopped.Although pig and nonhuman primates are biologically similar to humans, their genetic engineering is technically difficult, the cost of breeding is high, and the experimental time is long. As a result, the application of these species as model animals, especially genetically engineered model animals, in biomedical research is greatly limited.In terms of lipid metabolism and cardiovascular diseases, hamsters have several characteristics different from rats and mice, but similar to those in humans. The hamster is therefore an ideal animal model for studying lipid metabolism and cardiovascular disease because of its small size and short reproduction period. However, the phenomenon of zygote division, which was unexpectedly blocked during the manipulation of hamster embryos for some unknown reasons, had plagued researchers for decades and no genetically engineered hamsters have therefore been generated as animal models of human diseases for a long time. After solving the problem of in vitro development of hamster zygotes, we successfully prepared enhanced green fluorescent protein (eGFP) transgenic hamsters by microinjection of lentiviral vectors into the zona pellucida space of zygotes. On this basis, we started the development of cardiovascular disease models using the hamster embryo culture system combined with the novel genome editing technique of clustered regularly interspaced short palindromic repeats (CRISPR )/CRISPR associated protein 9 (Cas9). In this chapter, we will introduce some of the genetically engineered hamster models with dyslipidemia and the corresponding characteristics of these models. We hope that the genetically engineered hamster models can be further recognized and complement other genetically engineered animal models such as mice, rats, and rabbits. This will lead to new avenues and pathways for the study of lipid metabolism and its related diseases.

The Clinical Importance of Differentiating Monogenic Familial Hypercholesterolemia from Polygenic Hypercholesterolemia

PURPOSE OF REVIEW

The current review discusses the importance and significance of differentiating monogenic familial hypercholesterolemia (FH) from polygenic hypercholesterolemia for clinical purpose.

RECENT FINDINGS

Consistent scientific evidence have demonstrated that, compared to polygenic hypercholesterolemia, monogenic FH patients are at significantly higher risk for premature coronary heart disease (CHD). This is despite both disease entities having a comparable low-density-lipoprotein cholesterol (LDLC) level. Monogenic FH also has poorer therapeutic response compared to its polygenic counterpart. However, there are no current available clinical management guidelines that stratify hypercholesterolemia patients based on genotype. Monogenic FH patients are at higher risk for CHD with poorer therapeutic response. Thus, genotype testing should be performed when available. There is also an urgency to develop genotype-based clinical guideline that stratify patients on genotype and not only based on traditionally known cardiovascular risk factors.

Relations Between Familial Hypercholesterolemia and Early Ischemic Heart Disease: An Analysis of Medical Documentation Data

Heterozygous familial hypercholesterolemia is associated with a high risk of early ischemic heart disease onset and cardiovascular death. There is almost no data about the prevalence of the disease in the Ukrainian population. The aim of the study was to assess the incidence of familial hypercholesterolemia among patients who were treated in “L.T. Malaya Therapy National Institute of the National Academy of Medical Sciences of Ukraine” due to early ischemic heart disease. Medical records data of 600 patients treated in the Institute during 2015-2017 were analyzed. Early ischemic heart disease was diagnosed in 89 patients. The disease verification has been conducted either on the basis of coronarography data, or on the basis of previous myocardial infarction with Q wave. To identify patients with familial hypercholesterolemia, the Dutch lipid clinic network criteria were used. The presence of familial hypercholesterolemia was suspected in more than 14.8% of patients with early ischemic heart disease. Among these patients, 2 (2.2%) had definite diagnosis; 27 (30.3%) were likely to have diagnosis, 26 (29.7%) had possible diagnosis and in 34 (38,2%) patients it was unlikely to diagnose them with familial hypercholesterolemia. The term “familial hypercholesterolemia” was not mentioned in the hospital diagnosis. This paper demonstrates that despite frequent occurrence of familial hyper-cholesterolemia, doctors’ alertness towards this disease has been noted to be quite low.

An Untargeted Lipidomic Analysis Reveals Depletion of Several Phospholipid Classes in Patients with Familial Hypercholesterolemia on Treatment with Evolocumab

Rationale: Familial hypercholesterolemia (FH) is caused by mutations in genes involved in low-density lipoprotein cholesterol (LDL-C) metabolism, including those for pro-protein convertase subtilisin/kexin type 9 (PCSK-9). The effect of PCSK-9 inhibition on the plasma lipidome has been poorly explored. Objective: Using an ultra-high-performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry method, the plasma lipidome of FH subjects before and at different time intervals during treatment with the PCSK-9 inhibitor Evolocumab was explored. Methods and Results: In 25 FH subjects, heterozygotes or compound heterozygotes for different LDL receptor mutations, untargeted lipidomic revealed significant reductions in 26 lipid classes belonging to phosphatidylcholine (PC), sphingomyelin (SM), ceramide (CER), cholesteryl ester (CE), triacylglycerol (TG) and phosphatidylinositol (PI). Lipid changes were graded between baseline and 4- and 12-week treatment. At 12-week treatment, five polyunsaturated diacyl PC, accounting for 38.6 to 49.2% of total PC at baseline; two ether/vinyl ether forms; seven SM; five CER and glucosyl/galactosyl-ceramide (HEX-CER) were reduced, as was the unsaturation index of HEX-CER and lactosyl—CER (LAC-CER). Although non quantitative modifications were observed in phosphatidylethanolamine (PE) during treatment with Evolocumab, shorter and more saturated fatty acyl chains were documented. Conclusions: Depletion of several phospholipid classes occurs in plasma of FH patients during treatment with the PCSK-9 inhibitor Evolocumab. The mechanism underlying these changes likely involves the de novo synthesis of SM and CER through the activation of the key enzyme sphingomyelin synthase by oxidized LDL and argues for a multifaceted system leading to vascular improvement in users of PCSK-9 inhibitors.

Beneficial effects of PCSK9 inhibition with alirocumab in familial hypercholesterolemia involve modulation of new immune players

Familial hypercholesterolemia (FH) is associated with low-grade systemic inflammation, a key driver of premature atherosclerosis. We investigated the effects of inhibiting proprotein convertase subtilisin/kexin type 9 (PCSK9) function on inflammatory state, endothelial dysfunction and cardiovascular outcomes in patients with FH. Fourteen patients with FH were evaluated before and 8 weeks after administration of a PCSK9 blocking monoclonal antibody (alirocumab, 150 mg/subcutaneous/14 days). In vivo and ex vivo analysis revealed that alirocumab blunted the attachment of leukocytes to TNFα-stimulated human umbilical arterial endothelial cells (HUAEC) and suppressed the activation of platelets and most leukocyte subsets, which was accompanied by the diminished expression of CX₃CR1, CXCR6 and CCR2 on several leukocyte subpopulations. By contrast, T-regulatory cell activation was enhanced by alirocumab treatment, which also elevated anti-inflammatory IL-10 plasma levels and lowered circulating pro-inflammatory cytokines. Plasma levels of IFNγ positively correlated with levels of total and LDL-cholesterol, whereas circulating IL-10 levels negatively correlated with these key lipid parameters. In vitro analysis revealed that TNFα stimulation of HUAEC increased the expression of PCSK9, whereas endothelial PCSK9 silencing reduced TNFα-induced mononuclear cell adhesion mediated by Nox5 up-regulation and p38-MAPK/NFκB activation, concomitant with reduced SREBP2 expression. PCSK9 silencing also decreased endothelial CX₃CL1 and CXCL16 expression and chemokine generation. In conclusion, PCSK9 inhibition impairs systemic inflammation and endothelial dysfunction by constraining leukocyte-endothelium interactions. PCSK9 blockade may constitute a new therapeutic approach to control the inflammatory state associated with FH, preventing further cardiovascular events in this cardiometabolic disorder.

A Systematic Review and Meta-Analysis of Therapeutic Efficacy and Safety of Alirocumab and Evolocumab on Familial Hypercholesterolemia

Objectives

The aim of this study was to provide the first study to systematically analyze the efficacy and safety of PCSK9-mAbs in the treatment of familial hypercholesterolemia (FH).

Methods

A computer was used to search the electronic Cochrane Library, PubMed/MEDLINE, and Embase databases for clinical trials using the following search terms: "AMG 145", "evolocumab", "SAR236553/REGN727", "alirocumab", "RG7652", "LY3015014", "RN316/bococizumab", "PCSK9", and "familial hypercholesterolemia" up to November 2020. Study quality was assessed with the Cochrane Collaboration's tool, and publication bias was evaluated by a contour-enhanced funnel plot and the Harbord modification of the Egger test. After obtaining the data, a meta-analysis was performed using R software, version 4.0.3.

Results

A meta-analysis was performed on 7 clinical trials (926 total patients). The results showed that PCSK9-mAbs reduced the LDL-C level by the greatest margin, WMD -49.14%, 95% CI: -55.81 to -42.47%, on FH versus control groups. PCSK9-mAbs also significantly reduced lipoprotein (a) (Lp (a)), total cholesterol (TC), triglycerides (TG), apolipoprotein-B (Apo-B), and non-high-density lipoprotein cholesterol (non-HDL-C) levels and increased HDL-C and apolipoprotein-A1 (Apo-A1) levels of beneficial lipoproteins. Moreover, no significant difference was found between PCSK9-mAbs treatment and placebo in common adverse events, serious events, and laboratory adverse events.

Conclusion

PCSK9-mAbs significantly decreased LDL-C and other lipid levels with satisfactory safety and tolerability in FH treatment.

A Critical Review of the Efficacy and Safety of Inclisiran

The association between low-density cholesterol (LDL-C) and cardiovascular disease (CVD) is well-established, with an emphasis on lowering LDL-C levels to reduce cardiovascular events. Statin therapy has been the traditional treatment for LDL-C reduction, in addition to lifestyle modifications, but studies have shown that a substantial proportion of patients does not reach target LDL-C goals despite receiving maximally tolerated statin medications. Additionally, statin therapy is associated with a few shortcomings as many patients initiated on these medications discontinue treatment within 1 year because of lack of tolerability. Furthermore, guidelines from both the American College of Cardiology and the American Heart Association highlight the importance of obtaining LDL-C goals because of the residual atherosclerotic CVD risk that remains in high-risk populations. That the residual cardiovascular risk remains despite statin therapy highlights the importance of evaluating therapeutic approaches that possess effective lipid lowering that can be used adjunctively with statins. Much focus has been directed towards the proprotein convertase subtilisin/kexin type 9 (PCSK9) pathway, leading to the development of evolocumab and alirocumab, two human monoclonal antibodies directed against PCSK9. These agents have been shown to markedly decrease LDL-C levels and significantly reduce cardiovascular risk, but the need for biweekly or monthly subcutaneous injections has generated concerns for patient compliance. A new pathway is being studied in which a synthetic small interfering ribonucleic acid (siRNA) targets the PCSK9 gene expressed in hepatocytes to prevent PCSK9 production. The siRNA, inclisiran sodium, significantly reduces hepatic production of PCSK9, causing a marked reduction in LDL-C levels, and exhibits sustained pharmacodynamic effects when dosed subcutaneously every 6 months. This review presents and discusses the current clinical and scientific evidence pertaining to inclisiran sodium.

Primary hypercholesterolemia and development of cardiovascular disorders: Cellular and molecular mechanisms involved in low-grade systemic inflammation and endothelial dysfunction

Primary hypercholesterolemia, a metabolic disorder characterized by elevated circulating levels of cholesterol products, mainly low-density lipoproteins, is associated with arteriosclerosis development. Cardiovascular disease, predominantly myocardial infarction and stroke, remains the main cause of death worldwide, with atherosclerosis considered to be the most common underlying pathology. In addition to elevated plasma levels of low-density lipoproteins, low-grade systemic inflammation and endothelial dysfunction seem to be the main drivers of premature atherosclerosis. Here we review current knowledge related to cellular and molecular mechanisms involved in low-grade systemic inflammation and endothelial dysfunction associated with primary hypercholesterolemia. We also discuss the contribution of different inflammatory mediators, immune players and signaling pathways implicated in leukocyte adhesion to the dysfunctional endothelium, a key feature of atherogenesis development. A better understanding of these processes linked to primary hypercholesterolemia should shed new light on cardiovascular disease development and might guide novel and effective therapeutic strategies to impair its progression.

The LDLR c.501C>A is a disease-causing variant in familial hypercholesterolemia

Background

As an autosomal dominant disorder, familial hypercholesterolemia (FH) is mainly attributed to disease-causing variants in the low-density lipoprotein receptor (LDLR) gene. The aim of this study was to explore the molecular mechanism of LDLR c.501C>A variant in FH and assess the efficacy of proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitor treatment for FH patients.

Methods

The whole-exome sequencing was performed on two families to identify disease-causing variants, which were verified by Sanger sequencing. The function of LDLR variant was further explored in HEK293 cells by Western Blot and confocal microscopy. Besides, the therapeutic effects of PCSK9 inhibitor treatment for two probands were assessed for 3 months.

Results

All members of the two families with the LDLR c.501C>A variant showed high levels of LDLC. The relationship between the clinical phenotype and LDLR variants was confirmed in the current study. Both in silico and in vitro analyses showed that LDLR c.501C>A variant decreased LDLR expression and LDL uptake. PCSK9 inhibitor treatment lowered the lipid level in proband 1 by 24.91%. However, the treatment was ineffective for proband 2. A follow-up study revealed that the PCSK9 inhibitor treatment had low ability of lipid-lowering effect in the patients.

Conclusions

LDLR c.501C>A variant might be pathogenic for FH. The PCSK9 inhibitor therapy is not a highly effective option for treatment of FH patients with LDLR c.501C>A variant.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01536-3.

Characterization of familial hypercholesterolemia in Taiwanese ischemic stroke patients

Familial hypercholesterolemia (FH) is a common genetic disorder characterized by a lifelong elevated low-density lipoprotein cholesterol (LDL-C) level. The relationship between FH and ischemic stroke is still controversial. We enrolled ischemic stroke patients prospectively in our neurological ward, and divided them into two groups according to LDL-C levels with a threshold of 130 mg/dl. Targeted sequencing was performed in all stroke patients for LDLR, APOB, and PCSK9 genes. The fifty-eight high-LDL subjects were older, prevalence of previous myocardial infarction/stroke history was lower, and the first stroke age was older compared with values in the sixty-three low-LDL cases. The prevalence of FH in Han-Chinese stroke patients was 5.0%, and was 10.3% in those with a higher LDL-C level. We identified six carriers, who had higher percentages of large vessel stroke subtype (66.7% vs. 15.4%) and transient ischemic attack (33.3% vs. 3.8%), previous myocardial infarction/stroke history (50.0% vs. 11.5%), statin use (50.0% vs. 11.5%), and increased carotid intima-media thickness (IMT) (0.9-1.2mm vs.0.7-9.0mm) compared with the other hypercholesterolemic patients without pathogenic variants. Ischemic stroke patients carrying FH pathogenic variants seemed to have a higher risk for large artery stroke and transient ischemic attack. The IMT exam could be useful to screen for FH in hypercholesterolemic stroke patients.