Familial Hypercholesterolemia: JACC Focus Seminar 4/4

Evinacumab in homozygous familial hypercholesterolaemia: long-term safety and efficacy

BACKGROUND AND AIMS

Homozygous familial hypercholesterolaemia (HoFH) is a rare genetic disorder characterized by severely elevated LDL cholesterol (LDL-C) and premature atherosclerotic cardiovascular disease. In the pivotal Phase 3 HoFH trial (NCT03399786), evinacumab significantly decreased LDL-C in patients with HoFH. This study assesses the long-term safety and efficacy of evinacumab in adult and adolescent patients with HoFH.

METHODS

In this open-label, single-arm, Phase 3 trial (NCT03409744), patients aged ≥12 years with HoFH who were evinacumab-naïve or had previously received evinacumab in other trials (evinacumab-continue) received intravenous evinacumab 15 mg/kg every 4 weeks with stable lipid-lowering therapy.

RESULTS

A total of 116 patients (adults: n = 102; adolescents: n = 14) were enrolled, of whom 57 (49.1%) were female. Patients were treated for a median (range) duration of 104.3 (28.3-196.3) weeks. Overall, treatment-emergent adverse events (TEAEs) and serious TEAEs were reported in 93 (80.2%) and 27 (23.3%) patients, respectively. Two (1.7%) deaths were reported (neither was considered related to evinacumab). Three (2.6%) patients discontinued due to TEAEs (none were considered related to evinacumab). From baseline to Week 24, evinacumab decreased mean LDL-C by 43.6% [mean (standard deviation, SD), 3.4 (3.2) mmol/L] in the overall population; mean LDL-C reduction in adults and adolescents was 41.7% [mean (SD), 3.2 (3.3) mmol/L] and 55.4% [mean (SD), 4.7 (2.5) mmol/L], respectively.

CONCLUSIONS

In this large cohort of patients with HoFH, evinacumab was generally well tolerated and markedly decreased LDL-C irrespective of age and sex. Moreover, the efficacy and safety of evinacumab was sustained over the long term.

Advancements in risk stratification and management strategies in primary cardiovascular prevention

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of morbidity and mortality worldwide, highlighting the urgent need for advancements in risk assessment and management strategies. Although significant progress has been made recently, identifying and managing apparently healthy individuals at a higher risk of developing atherosclerosis and those with subclinical atherosclerosis still poses significant challenges. Traditional risk assessment tools have limitations in accurately predicting future events and fail to encompass the complexity of the atherosclerosis trajectory. In this review, we describe novel approaches in biomarkers, genetics, advanced imaging techniques, and artificial intelligence that have emerged to address this gap. Moreover, polygenic risk scores and imaging modalities such as coronary artery calcium scoring, and coronary computed tomography angiography offer promising avenues for enhancing primary cardiovascular risk stratification and personalised intervention strategies. On the other hand, interventions aiming against atherosclerosis development or promoting plaque regression have gained attention in primary ASCVD prevention. Therefore, the potential role of drugs like statins, ezetimibe, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, omega-3 fatty acids, antihypertensive agents, as well as glucose-lowering and anti-inflammatory drugs are also discussed. Since findings regarding the efficacy of these interventions vary, further research is still required to elucidate their mechanisms of action, optimize treatment regimens, and determine their long-term effects on ASCVD outcomes. In conclusion, advancements in strategies addressing atherosclerosis prevention and plaque regression present promising avenues for enhancing primary ASCVD prevention through personalised approaches tailored to individual risk profiles. Nevertheless, ongoing research efforts are imperative to refine these strategies further and maximise their effectiveness in safeguarding cardiovascular health.

Clinical impact of genetic testing for lipid disorders

PURPOSE OF REVIEW

Genetic testing is increasingly becoming a common consideration in the clinical approach of dyslipidemia patients. Advances in research in last decade and increased recognition of genetics in biological pathways modulating blood lipid levels created a gap between theoretical knowledge and its applicability in clinical practice. Therefore, it is very important to define the clinical justification of genetic testing in dyslipidemia patients.

RECENT FINDINGS

Clinical indications for genetic testing for most dyslipidemias are not precisely defined and there are no clearly established guideline recommendations. In patients with severe low-density lipoprotein cholesterol (LDL-C) levels, the genetic analysis can be used to guide diagnostic and therapeutic approach, while in severe hypertriglyceridemia (HTG), clinicians can rely on triglyceride level rather than a genotype along the treatment pathway. Genetic testing increases diagnostic accuracy and risk stratification, access and adherence to specialty therapies, and cost-effectiveness of cascade testing. A shared decision-making model between the provider and the patient is essential as patient values, preferences and clinical characteristics play a very strong role.

SUMMARY

Genetic testing for lipid disorders is currently underutilized in clinical practice. However, it should be selectively used, according to the type of dyslipidemia and when the benefits overcome costs.

Physical signs and atherosclerotic cardiovascular disease in familial hypercholesterolemia: the HELLAS-FH Registry

AIMS

Three physical signs, namely tendon xanthomas, corneal arcus and xanthelasma, have been associated with heterozygous familial hypercholesterolemia (heFH). The prevalence and clinical significance of these signs are not well established among contemporary heFH individuals. This study explored the frequency as well as the association of these physical signs with prevalent atherosclerotic cardiovascular disease (ASCVD) in heFH individuals.

METHODS

Data from the Hellenic Familial Hypercholesterolemia Registry were applied for this analysis. The diagnosis of heFH was based on the Dutch Lipid Clinic Network Score. Multivariate logistic regression analysis was conducted to examine the association of heFH-related physical signs with prevalent ASCVD.

RESULTS

Adult patients ( n  = 2156, mean age 50 ± 15 years, 47.7% women) were included in this analysis. Among them, 14.5% had at least one heFH-related physical sign present. The prevalence of corneal arcus before the age of 45 years was 6.6%, tendon xanthomas 5.3%, and xanthelasmas 5.8%. Among physical signs, only the presence of corneal arcus before the age of 45 years was independently associated with the presence of premature coronary artery disease (CAD). No association of any physical sign with total CAD, stroke or peripheral artery disease was found. Patients with physical signs were more likely to receive higher intensity statin therapy and dual lipid-lowering therapy, but only a minority reached optimal lipid targets.

CONCLUSION

The prevalence of physical signs is relatively low in contemporary heFH patients. The presence of corneal arcus before the age of 45 years is independently associated with premature CAD.

mRNA therapies: Pioneering a new era in rare genetic disease treatment

Rare genetic diseases, often referred to as orphan diseases due to their low prevalence and limited treatment options, have long posed significant challenges to our medical system. In recent years, Messenger RNA (mRNA) therapy has emerged as a highly promising treatment approach for various diseases caused by genetic mutations. Chemically modified mRNA is introduced into cells using carriers like lipid-based nanoparticles (LNPs), producing functional proteins that compensate for genetic deficiencies. Given the advantages of precise dosing, biocompatibility, transient expression, and minimal risk of genomic integration, mRNA therapies can safely and effectively correct genetic defects in rare diseases and improve symptoms. Currently, dozens of mRNA drugs targeting rare diseases are undergoing clinical trials. This comprehensive review summarizes the progress of mRNA therapy in treating rare genetic diseases. It introduces the development, molecular design, and delivery systems of mRNA therapy, highlighting their research progress in rare genetic diseases based on protein replacement and gene editing. The review also summarizes research progress in various rare disease models and clinical trials. Additionally, it discusses the challenges and future prospects of mRNA therapy. Researchers are encouraged to join this field and collaborate to advance the clinical translation of mRNA therapy, bringing hope to patients with rare genetic diseases.

Validation of the 2022 Clinical Diagnostic Criteria of Familial Hypercholesterolemia in Japan

AIM

In 2022, the Japan Atherosclerosis Society (JAS) has revised its clinical diagnostic criteria of familial hypercholesterolemia (FH) and adopted the use of definite, probable, possible, and unlikely FH according to the Dutch Lipid Clinic Network (DLCN) FH criteria. However, these strata have not been validated and their impact on coronary artery disease (CAD) is yet to be elucidated.

METHODS

In this study, we retrospectively examined the patients with FH aged ≥ 15 years (N=857, male=431) who were admitted to Kanazawa University Hospital between 2010 and 2022. We assessed the prevalence of patients with a pathogenic variant as FH and odds ratio (OR) of CAD among each group determined by the JAS criteria 2022 for adults.

RESULTS

In total, 414, 128, 142, and 173 patients were found to have definite, probable, possible, and unlikely FH, respectively, in this population. The prevalences of patients with a pathogenic variant as FH were 77.1%, 28.7%, 13.0%, and 1.2 %, respectively, among the definite, probable, possible, and unlikely FH patients (P-trend ＜0.001). Compared with the reference group of unlikely FH, patients with definite, probable, and possible FH were noted to have significantly higher adjusted odds of developing CAD (OR, 9.1; 95% confidence interval [CI], 3.2-12.6; P＜0.001 and OR, 4.2; 95% CI, 1.7-6.4; P＜0.001, and OR, 2.8; 95% CI, 1.2-4.4; P=0.002, respectively).

CONCLUSION

The new JAS diagnostic criteria for FH have been noted to work well in terms of diagnosing definitive, probable, or possible FH patients. Thus, it is seen to be of great help in terms of risk discrimination.

Management of lipid variables in primary cardiovascular prevention: A position paper from the Heart, Vessels and Metabolism Group of the French Society of Cardiology

Low-density lipoprotein cholesterol has been established as a powerful cardiovascular risk factor; its reduction provides a clinical benefit in primary cardiovascular prevention, irrespective of the characteristics of the patients treated. It is useful to tailor low-density lipoprotein cholesterol targets according to the magnitude of cardiovascular risk (low, high or very high) in order to reduce the cardiovascular risk as fully as possible. In order to provide a uniform approach, it is necessary to propose recommendations for good practice, defining strategies for reducing low-density lipoprotein cholesterol. It is also necessary to know their merits, to analyse their practical limits and to propose adaptations, taking into account limitations and national specifics. This position paper aims to analyse the contribution and limits, as well as the adaptation to French practice, of 2019 and 2021 European Society of Cardiology recommendations for the management of lipid variables and cardiovascular prevention.

LDLR c.415G > A causes familial hypercholesterolemia by weakening LDLR binding to LDL

BACKGROUND

Familial hypercholesterolemia (FH) is a prevalent hereditary disease that can cause aberrant cholesterol metabolism. In this study, we confirmed that c.415G > A in low-density lipoprotein receptor (LDLR), an FH-related gene, is a pathogenic variant in FH by in silico analysis and functional experiments.

METHODS

The proband and his family were evaluated using the diagnostic criteria of the Dutch Lipid Clinic Network. Whole-exome and Sanger sequencing were used to explore and validate FH-related variants. In silico analyses were used to evaluate the pathogenicity of the candidate variant and its impact on protein stability. Molecular and biochemical methods were performed to examine the effects of the LDLR c.415G > A variant in vitro.

RESULTS

Four of six participants had a diagnosis of FH. It was estimated that the LDLR c.415G > A variant in this family was likely pathogenic. Western blotting and qPCR suggested that LDLR c.415G > A does not affect protein expression. Functional studies showed that this variant may lead to dyslipidemia by impairing the binding and absorption of LDLR to low-density lipoprotein ( LDL).

CONCLUSION

LDLR c.415G > A is a pathogenic variant in FH; it causes a significant reduction in LDLR's capacity to bind LDL, resulting in impaired LDL uptake. These findings expand the spectrum of variants associated with FH.

Low Density Lipoprotein Cholesterol Decreases the Expression of Adenosine A2A Receptor and Lipid Rafts-Protein Flotillin-1: Insights on Cardiovascular Risk of Hypercholesterolemia

High blood levels of low-density lipoprotein (LDL)-cholesterol (LDL-C) are associated with atherosclerosis, mainly by promoting foam cell accumulation in vessels. As cholesterol is an essential component of cell plasma membranes and a regulator of several signaling pathways, LDL-C excess may have wider cardiovascular toxicity. We examined, in untreated hypercholesterolemia (HC) patients, selected regardless of the cause of LDL-C accumulation, and in healthy participants (HP), the expression of the adenosine A2A receptor (A2AR), an anti-inflammatory and vasodilatory protein with cholesterol-dependent modulation, and Flotillin-1, protein marker of cholesterol-enriched plasma membrane domains. Blood cardiovascular risk and inflammatory biomarkers were measured. A2AR and Flotillin-1 expression in peripheral blood mononuclear cells (PBMC) was lower in patients compared to HP and negatively correlated to LDL-C blood levels. No other differences were observed between the two groups apart from transferrin and ferritin concentrations. A2AR and Flotillin-1 proteins levels were positively correlated in the whole study population. Incubation of HP PBMCs with LDL-C caused a similar reduction in A2AR and Flotillin-1 expression. We suggest that LDL-C affects A2AR expression by impacting cholesterol-enriched membrane microdomains. Our results provide new insights into the molecular mechanisms underlying cholesterol toxicity, and may have important clinical implication for assessment and treatment of cardiovascular risk in HC.

Efficacy and safety of bempedoic acid in patients with heterozygous familial hypercholesterolemia: analysis of pooled patient-level data from phase 3 clinical trials

BACKGROUND

Patients with heterozygous familial hypercholesterolemia (HeFH) often cannot reach guideline-recommended low-density lipoprotein cholesterol (LDL-C) goals despite multidrug therapy.

OBJECTIVE

To evaluate the efficacy and safety of bempedoic acid as an add-on therapy for lowering LDL-C in patients with HeFH.

METHODS

Pooled data from two 52-week phase 3 clinical trials of patients with atherosclerotic cardiovascular disease and/or HeFH receiving maximally tolerated statin therapy (randomized 2:1 to bempedoic acid or placebo) were analyzed by HeFH status. Endpoints included changes from baseline to week 12 (and up to week 52) in LDL-C and other lipid parameters, achievement of LDL-C goals, and safety.

RESULTS

A total of 217 (bempedoic acid, 146; placebo, 71) patients with HeFH and 2,792 (bempedoic acid, 1,864; placebo, 928) without HeFH were included (mean baseline LDL-C, 172.8 mg/dL and 102.6 mg/dL, respectively). Bempedoic acid significantly lowered LDL-C at week 12 vs. placebo regardless of HeFH status (with HeFH, -21.2%; without HeFH, -18.2% [both P<0.0001]). Bempedoic acid significantly reduced other lipid parameters and high-sensitivity C-reactive protein vs. placebo regardless of HeFH status (all P≤0.01). Among patients with HeFH treated with bempedoic acid, 32% and 27% achieved LDL-C <100 mg/dL at weeks 12 and 52, respectively. Overall treatment-emergent adverse event incidence was comparable across all four groups (74.7-77.5%).

CONCLUSION

Bempedoic acid significantly lowered LDL-C levels vs. placebo and was generally well tolerated in all patients, with no new safety findings in patients with HeFH, despite more intensive lipid-lowering therapy in patients with vs. without HeFH.

Genetic Counseling and Genetic Testing for Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is one of the most common autosomal codominant Mendelian diseases. The major complications of FH include tendon and cutaneous xanthomas and coronary artery disease (CAD) associated with a substantial elevation of serum low-density lipoprotein levels (LDL). Genetic counseling and genetic testing for FH is useful for its diagnosis, risk stratification, and motivation for further LDL-lowering treatments. In this study, we summarize the epidemiology of FH based on numerous genetic studies, including its pathogenic variants, genotype-phenotype correlation, prognostic factors, screening, and usefulness of genetic counseling and genetic testing. Due to the variety of treatments available for this common Mendelian disease, genetic counseling and genetic testing for FH should be implemented in daily clinical practice.

Familial hypercholesterolemia is related to cardiovascular disease, heart failure and atrial fibrillation. Results from a population-based study

BACKGROUND

Familial hypercholesterolemia (FH) is associated with atherosclerotic cardiovascular disease (ASCVD). However, the prevalence of FH among a general population remains unknown, and it is unclear if FH is associated with other cardiovascular complications, including heart failure (HF) and atrial fibrillation (AF).

METHODS

Analyses were conducted on individuals without a prior history of cardiovascular disease using a nationwide health claims database collected in the JMDC Claims Database between 2005 and 2022 (n = 4,126,642; median age, 44 years; 57.5% men). We defined FH as either LDL cholesterol ≥250 mg/dL or LDL cholesterol ≥175 mg/dL under the lipid-lowering medications under the assumption that lipid-lowering medications reduced LDL cholesterol by 30%. We assessed the associations between FH and composite outcomes, including, ASCVD (myocardial infarction, angina pectoris, and stroke), HF, and AF using Cox proportional hazard model.

RESULTS

We identified 11,983 (.29%) FH patients. In total, 181,150 events were recorded during the mean follow-up period of 3.5 years. The status FH was significantly associated with composite outcomes after adjustments (hazard ratio [HR]; 1.38, 95% confidence interval [CI]: 1.30-1.47, p < .001). Interestingly, the status FH was significantly associated with HF (HR: 1.48, 95% CI: 1.36-1.61, p < .001) and AF (HR: 1.33, 95% CI: 1.08-1.64, p < .001) in addition to angina pectoris (HR: 1.45, 95% CI: 1.33-1.58, p < .001) and stroke (HR: 1.19, 95% CI: 1.04-1.36, p < .001).

CONCLUSION

We found that the prevalence of FH was .29% in a general population. FH was significantly associated with a higher risk of developing cardiovascular disease, HF and AF.

LAY SUMMARY

We sought to identify the prevalence of FH among a general population, and to clarify whether FH increases the risk of not only ASCVD but also HF and AF.

Unveiling Familial Hypercholesterolemia-Review, Cardiovascular Complications, Lipid-Lowering Treatment and Its Efficacy

Familial hypercholesterolemia (FH) is a genetic disorder primarily transmitted in an autosomal-dominant manner. We distinguish two main forms of FH, which differ in the severity of the disease, namely homozygous familial hypercholesterolemia (HoFH) and heterozygous familial hypercholesterolemia (HeFH). The characteristic feature of this disease is a high concentration of low-density lipoprotein cholesterol (LDL-C) in the blood. However, the level may significantly vary between the two mentioned types of FH, and it is decidedly higher in HoFH. A chronically elevated concentration of LDL-C in the plasma leads to the occurrence of certain abnormalities, such as xanthomas in the tendons and skin, as well as corneal arcus. Nevertheless, a significantly more severe phenomenon is leading to the premature onset of cardiovascular disease (CVD) and its clinical implications, such as cardiac events, stroke or vascular dementia, even at a relatively young age. Due to the danger posed by this medical condition, we have investigated how both non-pharmacological and selected pharmacological treatment impact the course of FH, thereby reducing or postponing the risk of clinical manifestations of CVD. The primary objective of this review is to provide a comprehensive summary of the current understanding of FH, the effectiveness of lipid-lowering therapy in FH and to explain the anatomopathological correlation between FH and premature CVD development, with its complications.

International Atherosclerosis Society guidance for implementing best practice in the care of familial hypercholesterolaemia

This contemporary, international, evidence-informed guidance aims to achieve the greatest good for the greatest number of people with familial hypercholesterolaemia (FH) across different countries. FH, a family of monogenic defects in the hepatic LDL clearance pathway, is a preventable cause of premature coronary artery disease and death. Worldwide, 35 million people have FH, but most remain undiagnosed or undertreated. Current FH care is guided by a useful and diverse group of evidence-based guidelines, with some primarily directed at cholesterol management and some that are country-specific. However, none of these guidelines provides a comprehensive overview of FH care that includes both the lifelong components of clinical practice and strategies for implementation. Therefore, a group of international experts systematically developed this guidance to compile clinical strategies from existing evidence-based guidelines for the detection (screening, diagnosis, genetic testing and counselling) and management (risk stratification, treatment of adults or children with heterozygous or homozygous FH, therapy during pregnancy and use of apheresis) of patients with FH, update evidence-informed clinical recommendations, and develop and integrate consensus-based implementation strategies at the patient, provider and health-care system levels, with the aim of maximizing the potential benefit for at-risk patients and their families worldwide.

Primary Prevention of Subclinical Atherosclerosis in Young Adults: JACC Review Topic of the Week

There is growing evidence that the atherosclerotic process that leads to symptomatic cardiovascular disease (CVD) starts at an early age. In young adults, exposure to low-density lipoprotein-cholesterol and other cardiovascular risk factor (CVRF) mediators, even at levels considered within normal limits, increases the prevalence of subclinical atherosclerosis and is associated with greater risk of cardiovascular events later in life. The optimal CVRF targets to prevent CVD in asymptomatic young individuals (<40 years) are unknown. The randomized controlled PRECAD (Prevent Coronary Artery Disease) trial has been developed to assess the potential benefit of an aggressive control of CVRF in otherwise healthy young adults. The hypothesis of PRECAD is that in subjects aged 20 to 39 years without known CVD, maintaining low-density lipoprotein-cholesterol <70 mg/dL and strict control of blood pressure and glucose will prevent the onset of atherosclerosis and/or its progression. The primary endpoint will be the change in total atherosclerosis burden, a surrogate for CVD.

Impact of the severe familial hypercholesterolemia status on atherosclerotic risks

Risks of atherosclerotic events substantially vary even among patients with familial hypercholesterolemia (FH) with extremely high risk based on life-long exposure to high low-density lipoprotein cholesterol levels. This study aimed to examine the impact of the severe FH status defined by the International Atherosclerosis Society (IAS). Data of patients with FH (N = 1050, male = 490) who were admitted to Kanazawa University Hospital between 2000 and 2020 and who were followed up were retrospectively reviewed. The number of major adverse cardiac events (MACEs), including mortality associated with cardiovascular disease, acute coronary syndrome, and ischemic heart disease requiring coronary revascularization per 1000 person-years, was calculated. Hazard ratio was also calculated using Cox proportional model. Overall, 545 (51.9%) patients had severe FH. The median follow-up duration was 12.6 years. In total, 171 MACEs were recorded during the follow-up period. Severe FH was significantly associated with MACE (hazard ratio = 6.48, 95% confidence interval = 2.56-10.40, P = 1.2 × 10-5). The event rates per 1000 person-years in the primary prevention group of non-severe FH and severe FH, were 0.0 and 15.6, respectively. The event rates per 1000 person-years in the secondary prevention group of non-severe FH and severe FH, were 2.0 and 32.3, respectively. Patients with severe FH exhibited significantly higher risks in primary and secondary prevention settings. This simple criterion provides useful information for identifying patients with even higher risk who may need further management.

Approach to the Patient With a Suboptimal Statin Response: Causes and Algorithm for Clinical Management

CONTEXT

Statins are the lipid-lowering therapy of choice for the prevention of atherosclerotic cardiovascular disease (ASCVD) but their effectiveness in lowering low-density lipoprotein cholesterol (LDL-C) can substantially differ between individuals. In this mini-review, we describe the different causes for a suboptimal statin response and an algorithm for the diagnosis and clinical management of these patients.

EVIDENCE ACQUISITION

A PubMed search using the terms "statin resistance," "statin sensitivity," "statin pharmacokinetics," "cardiovascular disease," and "lipid-lowering therapies" was performed. Published papers in the past 10 years that were relevant to the topic were examined to provide content for this mini-review.

EVIDENCE SYNTHESIS

Suboptimal lowering of LDL-C by statins is a major problem in the clinical management of patients and limits the value of this therapeutic approach. There are multiple causes of statin hyporesponsiveness with compliance being the most common explanation. Other causes, such as analytical issues with LDL-C measurement and the presence of common lipid disorders (familial hypercholesterolemia, elevated lipoprotein[a] and secondary dyslipidemias) should be excluded before considering primary statin resistance from rare genetic variants in lipoprotein-related or drug-metabolism genes. A wide variety of nonstatin lipid-lowering drugs are now available and can be added to statins to achieve more effective LDL-C lowering.

CONCLUSIONS

The evaluation of statin hyporesponsiveness is a multistep process that can lead to the optimization of lipid-lowering therapy for the prevention of ASCVD. It may also lead to the identification of distinct types of dyslipidemias that require specific therapies and/or the genetic screening of family members.

Recent advances in the management and implementation of care for familial hypercholesterolaemia

Familial hypercholesterolaemia (FH) is a common autosomal semi-dominant and highly penetrant disorder of the low-density lipoprotein (LDL) receptor pathway, characterised by lifelong elevated levels of low-density lipoprotein cholesterol (LDL-C) and increased risk of atherosclerotic cardiovascular disease (ASCVD). However, many patients with FH are not diagnosed and do not attain recommended LDL-C goals despite maximally tolerated doses of potent statin and ezetimibe. Over the past decade, several cholesterol-lowering therapies such as those targeting proprotein convertase subtilisin/kexin type 9 (PCSK9) or angiopoietin-like 3 (ANGPTL3) with monoclonal antibody or ribonucleic acid (RNA) approaches have been developed that promise to close the treatment gap. The availability of new therapies with complementary modes of action of lipid metabolism has enabled many patients with FH to attain guideline-recommended LDL-C goals. Emerging therapies for FH include liver-directed gene transfer of the LDLR, vaccines targeting key proteins involved in cholesterol metabolism, and CRISPR-based gene editing of PCSK9 and ANGPTL3, but further clinical trials are required. In this review, current and emerging treatment strategies for lowering LDL-C, and ASCVD risk-stratification, as well as implementation strategies for the care of patients with FH are reviewed.

In vitro assessment of the pathogenicity of the LDLR c.2160delC variant in familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH) is an inherited disorder with markedly elevated low-density lipoprotein cholesterol (LDL-C) and premature atherosclerotic cardiovascular disease. Although many mutations have been reported in FH, only a few have been identified as pathogenic mutations. This study aimed to confirm the pathogenicity of the LDL receptor (LDLR) c.2160delC variant in FH.

METHODS

In this study, the proband and her family members were systematically investigated, and a pedigree map was drawn. High-throughput whole-exome sequencing was used to explore the variants in this family. Next, quantitative polymerase chain reaction (qPCR), western blot (WB) assays, and flow cytometry were conducted to detect the effect of the LDLR c.2160delC variant on its expression. The LDL uptake capacity and cell localization of LDLR variants were analyzed by confocal microscopy.

RESULTS

According to Dutch Lipid Clinic Network (DLCN) diagnostic criteria, three FH patients were identified with the LDLR c.2160delC variant in this family. An in-silico analysis suggested that the deletion mutation at the 2160 site of LDLR causes a termination mutation. The results of qPCR and WB verified that the LDLR c.2160delC variant led to early termination of LDLR gene transcription. Furthermore, the LDLR c.2160delC variant caused LDLR to accumulate in the endoplasmic reticulum, preventing it from reaching the cell surface and internalizing LDL.

CONCLUSIONS

The LDLR c.2160delC variant is a terminating mutation that plays a pathogenic role in FH.

Coronary artery calcium among patients with heterozygous familial hypercholesterolaemia

Aims

We aimed to determine if coronary artery calcium (CAC) is associated with cardiovascular disease (CVD) events, defined as CVD-related death, unstable angina, myocardial infarction, or staged revascularization among patients with heterozygous familial hypercholesterolaemia (HeFH) under primary prevention settings.

Methods and results

Data of patients with FH admitted to Kanazawa University Hospital between 2000 and 2020, who underwent CAC measurement and were followed up (n = 622, male = 306, mean age = 54 years), were retrospectively reviewed. Risk factors for CVD events were determined using the Cox proportional hazard model. The median follow-up duration was 13.2 years (interquartile range: 9.8-18.4 years). We observed 132 CVD events during the follow-up period. The event rate per 1000 person-years for CAC scores of 0 [n = 283 (45.5%)], 1-100 [n = 260 (41.8%)], and >100 [n = 79 (12.7%)] was 1.2, 17.0, and 78.8, respectively. Log (CAC score + 1) was a significant predictor of the occurrence of CVD events (hazard ratio: 3.24; 95% confidence interval: 1.68-4.80; P < 0.0001) in the multivariate Cox regression analysis, independent of other factors. The risk discrimination of CVD events was enhanced by adding CAC information to other conventional risk factors (C-statistics: 0.833-0.934; P < 0.0001).

Conclusion

The CAC score helps in further risk stratification in patients with HeFH.

Attainment of the low-density lipoprotein cholesterol treatment target and prognosis of heterozygous familial hypercholesterolemia

BACKGROUND AND AIMS

No previous study has investigated the association between attainment of low-density lipoprotein (LDL) cholesterol treatment target and better prognosis in patients with familial hypercholesterolemia (FH). The current research aimed to examine the association between attainment of LDL cholesterol treatment target and major adverse cardiac events (MACEs) in patients with FH to validate the current LDL cholesterol treatment targets in primary (<100 mg/dL) and secondary (<70 mg/dL) prevention settings.

METHODS

The data of patients with FH who were admitted to Kanazawa University Hospital between 2000 and 2020 and who were followed-up were retrospectively reviewed. The number of MACEs, including mortality associated with cardiovascular disease, unstable angina, and myocardial infarction per 1000 person-years, was calculated for each stratum for the attainment of LDL cholesterol target.

RESULTS

The median follow-up duration was 12.6 years. In total, 132 MACEs were recorded during the follow-up period. The numbers of patients who attained the LDL cholesterol target in the primary and secondary prevention groups were 228 (31.9%) and 40 (11.9%), respectively. The event rates per 1000 person-years for LDL cholesterol levels of <100 and ≥100 mg/dL in the primary prevention group were 2.6 and 4.4, respectively. The event rates per 1000 person-years for LDL cholesterol levels of <70 and ≥70 mg/dL in the secondary prevention group were 15.3 and 27.5, respectively.

CONCLUSIONS

Attainment of the LDL cholesterol target is associated with better prognosis in patients with FH. However, the attainment rate is currently inadequate among Japanese.

Gene editing for dyslipidemias: New tools to "cut" lipids

Effective lipid lowering therapies are essential for the prevention of atherosclerosis and cardiovascular disease. Available treatments have evolved in both their efficacy and their frequency of administration, and currently include monoclonal antibodies, antisense oligonucleotides and siRNA approaches. However, an unmet need remains for more effective and long-lasting therapeutics. Gene editing permanently alters endogenous gene expression and has the potential to revolutionize disease treatment. Despite the existence of several gene editing approaches, the CRISPR/Cas9 system has emerged as the preferred technology because of its high efficiency and relative simplicity. This review provides a general overview of this promising technology and an update on the progress made towards the development of treatments of dyslipidemia. The recently started phase 1b gene editing clinical trial targeting PCSK9 in patients with heterozygous familial hypercholesterolemia and cardiovascular disease highlights how gene editing may become available to treat not only patients affected by rare disorders of lipid metabolism, but also patients that are difficult-to-treat or at high risk. Other targets like ANGPTL3, LDLR, and APOC3 are on track for further pre-clinical development. The identification of novel targets using electronic health record-linked biobanks and human sequencing studies will continue to expand the potential target pool, and clinical assessment of treated patients will provide essential efficacy and safety information on current strategies. Gene editing of genes regulating lipid metabolism holds promise as an exciting new therapeutic approach. However, since gene editing permanently alters a patient's genome, its therapeutic application in humans will require careful safety assessment and ethical considerations.

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.

Synergistic effect of lipoprotein (a) and C-reactive protein on prognosis of familial hypercholesterolemia

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Lp(a) levels among patients with pathogenic variant FH were significantly elevated.

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Lp(a) and CRP levels were not associated with MACE by themselves.

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Lp(a) level was significantly associated with MACE only when the CRP level was elevated.

Objective

The synergistic effect of lipoprotein (a) [Lp(a)] and C-reactive protein (CRP) on major adverse cardiovascular events (MACE) among patients with familial hypercholesterolemia (FH) is unknown. This study aimed to investigate the relations between Lp(a) and CRP levels and MACE in patients with FH whose Lp(a) levels are elevated.

Methods

We retrospectively investigated associations between genotypes and phenotypes, including low-density lipoprotein (LDL) cholesterol level and the occurrence of MACE among patients with FH (N = 786, male/female: 374/412). A Cox proportional hazard model was used to identify factors associated with MACE, adjusting for traditional risk factors. Patients with FH were divided into four groups, based on their Lp(a) and CRP levels, and assessed using Kaplan–Meier curves.

Results

The median follow-up was 12.6 years (interquartile range [IQR], 9.5–17.9 years). During follow-up, 129 MACE were observed. Median Lp(a) and CRP levels were 21.4 (10.9–38.3) mg/dL and 0.20 (0.11–0.29) mg/dL, respectively. Under these conditions, natural log-transformed Lp(a) and CRP were not associated with MACE (hazard ratio [HR], 1.08; 95% confidence interval [CI], 0.91–1.25; P = 0.220; and HR, 1.12; CI, 0.96–1.28; P = 0.190, respectively). However, in Group 4, Lp(a) and CRP were significantly associated with MACE (HR, 2.44; CI, 1.42–3.46; P = 1.8 × 10⁻⁷).

Conclusions

In patients with FH, Lp(a) was significantly associated with MACE only when the CRP level was elevated. Patients with FH whose Lp(a) and CRP levels are elevated should be treated aggressively.

World Heart Federation Cholesterol Roadmap 2022

Background:

Atherosclerotic cardiovascular diseases (ASCVD) including myocardial infarction, stroke and peripheral arterial disease continue to be major causes of premature death, disability and healthcare expenditure globally. Preventing the accumulation of cholesterol-containing atherogenic lipoproteins in the vessel wall is central to any healthcare strategy to prevent ASCVD. Advances in current concepts about reducing cumulative exposure to apolipoprotein B (apo B) cholesterol-containing lipoproteins and the emergence of novel therapies provide new opportunities to better prevent ASCVD. The present update of the World Heart Federation Cholesterol Roadmap provides a conceptual framework for the development of national policies and health systems approaches, so that potential roadblocks to cholesterol management and thus ASCVD prevention can be overcome.

Methods:

Through a review of published guidelines and research papers since 2017, and consultation with a committee composed of experts in clinical management of dyslipidaemias and health systems research in low-and-middle income countries (LMICs), this Roadmap identifies (1) key principles to effective ASCVD prevention (2) gaps in implementation of these interventions (knowledge-practice gaps); (3) health system roadblocks to treatment of elevated cholesterol in LMICs; and (4) potential strategies for overcoming these.

Results:

Reducing the future burden of ASCVD will require diverse approaches throughout the life-course. These include: a greater focus on primordial prevention; availability of affordable cholesterol testing; availability of universal cholesterol screening for inherited dyslipidaemias; risk stratification moving beyond 10-year risk to look at lifetime risk with adequate risk estimators; wider availability of affordable cholesterol-lowering therapies which should include statins as essential medications globally; use of adequate doses of potent statin regimens; and combination therapies with ezetimibe or other therapies in order to attain and maintain robust reductions in LDL-C in those at highest risk. Continuing efforts are needed on health literacy for both the public and healthcare providers, utilising multi-disciplinary teams in healthcare and applications that quantify both ASCVD risk and benefits of treatment as well as increased adherence to therapies.

Conclusions:

The adverse effects of LDL-cholesterol and apo B containing lipoprotein exposure are cumulative and result in ASCVD. These are preventable by implementation of different strategies, aimed at efficiently tackling atherosclerosis at different stages throughout the human life-course. Preventive strategies should therefore be updated to implement health policy, lifestyle changes and when needed pharmacotherapies earlier with investment in, and a shift in focus towards, early preventive strategies that preserve cardiovascular health rather than treat the consequences of ASCVD.

[Lipid lowering: new agents and new concepts]

Low-density lipoprotein (LDL) cholesterol (LDL-C) is a causal risk factor for cardiovascular complications. A target value is set according to risk, guideline-based and individual basis. We now have the means to lower LDL‑C levels to ranges that are even associated with plaque volume regression. Moreover, lipid treatment is an example of how pharmacotherapy has evolved from classical selective inhibition of enzymes by drugs (e.g. statins) to targeted neutralization of proteins by antibodies. The reduction of atherogenic lipoproteins by specific inhibition or reduction of mRNA of target proteins, e.g. PCSK‑9, ANGPLT3, ApoC-III or Apo (a), and possibly one day by vaccination or even CRISP-based gene therapy will in the long term lead to new concepts in the treatment and prevention of dyslipidemia and cardiovascular complications. The cumulative exposure of atherogenic lipoproteins to the vessel wall is determined by the time-averaged LDL‑C level. This essentially depends on patient adherence and prescribed treatment intensity by physicians. Therefore, it is likely that treatment adherence influences the cumulative benefit of treatment. Accordingly, the new therapeutic strategies mentioned above with presumably higher adherence rates could help to optimize cardiovascular prevention. Early and effective LDL‑C lowering could drastically reduce the incidence of cardiovascular complications in the long term and help to maintain the health of our patients.

Regulation of cholesterol homeostasis in health and diseases: from mechanisms to targeted therapeutics

Disturbed cholesterol homeostasis plays critical roles in the development of multiple diseases, such as cardiovascular diseases (CVD), neurodegenerative diseases and cancers, particularly the CVD in which the accumulation of lipids (mainly the cholesteryl esters) within macrophage/foam cells underneath the endothelial layer drives the formation of atherosclerotic lesions eventually. More and more studies have shown that lowering cholesterol level, especially low-density lipoprotein cholesterol level, protects cardiovascular system and prevents cardiovascular events effectively. Maintaining cholesterol homeostasis is determined by cholesterol biosynthesis, uptake, efflux, transport, storage, utilization, and/or excretion. All the processes should be precisely controlled by the multiple regulatory pathways. Based on the regulation of cholesterol homeostasis, many interventions have been developed to lower cholesterol by inhibiting cholesterol biosynthesis and uptake or enhancing cholesterol utilization and excretion. Herein, we summarize the historical review and research events, the current understandings of the molecular pathways playing key roles in regulating cholesterol homeostasis, and the cholesterol-lowering interventions in clinics or in preclinical studies as well as new cholesterol-lowering targets and their clinical advances. More importantly, we review and discuss the benefits of those interventions for the treatment of multiple diseases including atherosclerotic cardiovascular diseases, obesity, diabetes, nonalcoholic fatty liver disease, cancer, neurodegenerative diseases, osteoporosis and virus infection.

The Progression of Treatment for Refractory Hypercholesterolemia: Focus on the Prospect of Gene Therapy

Refractory hypercholesterolemia (RH), including homozygous familial hypercholesterolemia (HoFH) and compound heterozygous familial hypercholesterolemia, is characterized by high levels of low-density lipoprotein cholesterol (LDL-C) despite existing cholesterol-lowering methods at maximal tolerable doses. Patients with RH have early onset and higher risk of atherosclerotic cardiovascular disease (ASCVD) under insufficient treatment. Therefore, it is urgent to seek new therapies to maintain the blood lipids in refractory hyperlipidemia at normal levels. Currently, new cholesterol-lowering strategies are on the market, not only at the protein level [i.e., bempedoic acid (inhibiting ATP-citrate lyase), alirocumab and evolocumab (monoclonal antibodies against PCSK9), evinacumab (monoclonal antibody against ANGPTL3)] but also at the transcript level [i.e., mipomersen (antisense oligonucleotide inhibiting ApoB), inclisiran (siRNA targeting PCSK9)], providing more options for RH patients to achieve their lipid-lowering targets. More RNA-based therapies targeting RH-related genes have been designed for the treatment. However, for a proportion of patients, especially those with LDLR deficiency, the available treatments are still insufficient. More recently, emerging genome engineering based on CRISPR/Cas9 techniques, and advanced delivery technologies such as lentiviral vectors, adenoviral vectors, adeno-associated viral vectors, lipid nanoparticles, and exosomes are being rapidly developed and implemented as novel therapies for RH. Gene therapy targeting RH-related genes has been successfully conducted in cells, mice, and non-human primates with high efficacy in lipid lowering and good tolerability. Especially the new generation of genome editing technique, base editing, performed in vivo with ideal lipid-lowering effect and limited occurrence of unwanted results. Excitingly, a phase I/II clinical study of LDLR gene replacement has been recently completed in RH patients, likely to be employed in clinical practice in the future. Furthermore, new targets for cholesterol reduction such as REV-ERB, G protein-coupled receptor, Ubiquitin specific peptidase 20 are continually being developed. This narrative review updates recent advances in treatment for RH, summarizes related clinical trials and preclinical studies, especially on the prospect of gene therapy.

The Genetic Spectrum of Familial Hypertriglyceridemia in Oman

Familial hypertriglyceridemia (F-HTG) is an autosomal disorder that causes severe elevation of serum triglyceride levels. It is caused by genetic alterations in LPL, APOC2, APOA5, LMF1, and GPIHBP1 genes. The mutation spectrum of F-HTG in Arabic populations is limited. Here, we report the genetic spectrum of six families of F-HTG of Arab ancestry in Oman. Methods: six Omani families affected with triglyceride levels >11.2 mmol/L were included in this study. Ampli-Seq sequencing of the selected gene panels was performed. Whole-exome sequencing and copy number variant analysis were also performed in cases with negative exome results. Three novel pathogenic missense variants in the LPL gene were identified, p.M328T, p.H229L, and p.S286G, along with a novel splice variant c.1322+15T > G. The LPL p.H229L variant existed in double heterozygous mutation with the APOA5 gene p.V153M variant. One family had a homozygous mutation in the LMF1 gene (c.G107A; p.G36D) and a heterozygous mutation in the LPL gene (c.G106A; p.D36N). All affected subjects did not have a serum deficiency of LPL protein. Genetic analysis in one family did not show any pathogenic variants even after whole-exome sequencing. These novel LPL and APOA5 mutations are not reported in other ethnic groups. This suggests that patients with F-HTG in Oman have a founder effect and are genetically unique. This warrants further analysis of patients of F-HTG in the Middle East for preventative and counseling purposes to limit the spread of the disease in a population of high consanguinity.

The role of RNA binding proteins in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of overall cancer deaths worldwide with limited therapeutic options. Due to the heterogeneity of HCC pathogenesis, the molecular mechanisms underlying HCC development are not fully understood. Emerging evidence indicates that RNA-binding proteins (RBPs) play a vital role throughout hepatocarcinogenesis. Thus, a deeper understanding of how RBPs contribute to HCC progression will provide new tools for early diagnosis and prognosis of this devastating disease. In this review, we summarize the tumor suppressive and oncogenic roles of RBPs and their roles in hepatocarcinogenesis. The diagnostic and therapeutic potential of RBPs in HCC, including their limitations, are also discussed.