Familial Hypercholesterolemia: New Horizons for Diagnosis and Effective Management

Low-Density Lipoprotein Receptor Apolipoprotein B Gene Polymorphism in Kurdish Patients With Severe Hypercholesterolemia

Background Polymorphisms in the low-density lipoprotein receptor (LDLR) and apolipoprotein B 100 (APOB-100) genes have been linked to severe hypercholesterolemia in several populations. This study investigated the frequency of LDLR-Ava II and APOB-Xba I polymorphisms among Kurdish patients with severe hypercholesterolemia. Methodology We investigated LDLR-Ava II and APOB-Xba I gene polymorphisms in Kurdish patients attending the Duhok Specialized Laboratory Center in Duhok, Kurdistan Region, Iraq. We included a total of 80 subjects in this study, of which 40 (20 males and 20 females) had severe hypercholesterolemia, and 40 apparently healthy volunteers (21 males and 19 females) had normocholesterolemia, served as a control group. We used the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique to determine the polymorphisms of the LDLR-Ava II and APOB-Xba I genes. Results In those with severe hypercholesterolemia, the observed allele frequencies were AA LDLR-Ava II polymorphism (eight, 20%) followed by TT APOB-Xba I polymorphisms (six, 15%), whereas these frequencies were five (12.5%) and one (2.5%) in those with normocholesterolemia, respectively. The AA genotype group had considerably higher cholesterol and LDL-C levels compared with the GG genotype group. A similar pattern was observed when comparing the TT and CC genotype groups. Conclusions Our results showed a high frequency of AA LDLR-Ava II polymorphism in conjunction with TT APOB-Xba I polymorphism which may be strongly associated with hypercholesterolemia in the Kurdish population.

A study on cholesterol-cholesteryl ester metabolic homeostasis and drug intervention in hyperlipidemic hamsters using UHPLC-MS/MS

Hyperlipidemia is a global metabolic disorder characterized by dysregulation of lipid metabolism. This dysregulation is closely associated with the altered homeostasis of cholesterol-cholesteryl ester (CE) metabolism in systemic circulation, and some organs. Additionally, the relationship between oxidized cholesteryl ester (oxCE) and the disease has also gained attention. Currently, there is a lack of comprehensive research on the alterations in cholesterol-CE metabolism in the context of hyperlipidemia, as well as the characteristics of lipid-lowering agents in regulating this metabolic state. Therefore, 40 oxCEs were identified in the hamster liver sample, and novel ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) methods were established for simultaneous analysis of cholesterol, 57 CEs, and 40 oxCEs in the serum, liver, adipose tissue, and intestine of hyperlipidemic hamsters. This study investigated the metabolic alterations between cholesterol-CE/oxCE in hyperlipidemic hamsters and those treated with lipid-lowering agents, including the Niemann-Pick-C1 like-1 protein (NPC1L1) inhibitor ezetimibe and the acyl coenzyme A: cholesterol acyltransferase (ACAT) inhibitor avasimibe. The study findings demonstrate metabolic disorders in cholesterol-CE/oxCE homeostasis in hyperlipidemic hamsters. Lipid-lowering agent therapy can improve the metabolic dysregulation caused by hyperlipidemia, with distinct characteristics: ezetimibe is more effective in reducing cholesterol, while avasimibe is more effective in reducing CEs/oxCEs. Eight potential biomarkers indicating the dysregulation of cholesterol-CE metabolism caused by hyperlipidemia and its improvement by lipid-lowering agents have been identified in the serum. This study offers new insights into the hyperlipidemia pathophysiology and the mechanisms of lipid-lowering agents from a novel perspective on cholesterol-CE/oxCE metabolic homeostasis.

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.

Beyond cardiovascular risk: Implications of Familial hypercholesterolemia on cognition and brain function

Familial hypercholesterolemia (FH) is a metabolic condition caused mainly by a mutation in the low-density lipoprotein (LDL) receptor gene (LDLR), which is highly prevalent in the population. Besides being an important causative factor of cardiovascular diseases, FH has been considered an early risk factor for Alzheimer's disease. Cognitive and emotional behavioral impairments in LDL receptor knockout (LDLr-/-) mice are associated with neuroinflammation, blood-brain barrier dysfunction, impaired neurogenesis, brain oxidative stress, and mitochondrial dysfunction. Notably, today, LDLr-/- mice, a widely used animal model for studying cardiovascular diseases and atherosclerosis, are also considered an interesting tool for studying dementia. Here, we reviewed the main findings in LDLr-/- mice regarding the relationship between FH and brain dysfunctions and dementia development.

Efficacy and Safety of Alirocumab and Evolocumab as Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Inhibitors in Familial Hypercholesterolemia: A Systematic Review and Meta-Analysis

BACKGROUND

Familial hypercholesterolemia (FH) is a prevalent and potentially fatal illness that causes a substantial elevation in low-density lipoprotein cholesterol (LDL-C).

OBJECTIVE

The aim of this study was to investigate the effects of monoclonal antibodies alirocumab and evolocumab on LDL-C and other lipid parameters, as well as their safety in familial hypercholesterolemia patients.

METHODS

A comprehensive search was done on PubMed/MEDLINE, EMBASE, Web of Science (WOS/ ISI), Scopus, ClinicalTrials (www.

CLINICALTRIALS

gov), and conferences/ congress research papers. Random effect models were used to calculate mean differences (%) and risk ratios (RRs), and confidence intervals (95%).

RESULTS

Ten studies (n=1489 patients) were included in this study. PCSK9 inhibitors decreased the levels of LDL-C by -49.59% (95%CI -55.5%, -43.67%) as compared to placebo. They also didn't alter the Treatment-Emergent Adverse Event (TEAE) and neuronal events by RR 0.92 (0.75, 1.13) and 1.31 (0.66, 2.59), respectively. PCSK9 inhibitors were effective and safe in treating patients with FH.

CONCLUSION

There was high-quality evidence showing that monoclonal antibodies (alirocumab & evolocumab) lower LDL-C (GRADE: high), lipoprotein (a) (GRADE: High), triglycerides (TG) (GRADE: High), total cholesterol (GRADE: High), non-high-density lipoprotein cholesterol (non- HDL-C) (GRADE: Moderate), and apolipoprotein B (GRADE: High), and increase the HDL-C (GRADE: High) as well as apolipoprotein A1 (GRADE: High). Comparing PCSK9 inhibitors against placebo, neither TEAE (GRADE: high) nor neuronal events (GRADE: moderate) were changed.

A retrospective study: efficacy of an originator versus a generic formulation of simvastatin in patients who suffer from hyperlipidaemia

BACKGROUND

South Africa is home to a multi-ethnic society with a large range of cultures and lifestyles. Cardiovascular disease is a major cause of morbidity and mortality. South Africa is known to have one of the highest incidence rates of hypercholesterolaemia in the world, especially among the Caucasian population.

AIM

The aim of this retrospective chart review was to establish whether a multisource simvastatin (Simvotin®, Ranbaxy, a Sun Pharma company) maintained the cholesterol-lowering effect after switching from the innovator brand Zocor® (MSD South Africa) in the public-sector hospitals. Since prescribers often doubt the registration requirements of multisource products based on bioequivalence alone, this research was done to confirm similar clinical outcomes in a real-world setting.

METHODS

More than 200 charts were identified from patients treated for hyperlipidaemia. Patients were treated for at least six months prior to and again six months after the switching of brands in order to meet criteria to be eligible for inclusion. The lipid values at initiation of therapy as well as before switching (visit 1 and 2) had to be available and again six months after treatment on the multisource product (visit 3).

RESULTS

No significant change was observed in the lipid control after switching, confirming similarity.

CONCLUSION

This real-world evidence should allay any fears of generic inferiority of this important medicine in the treatment and prevention of high cardiovascular risk in patients requiring lipid-lowering therapy.

Genetic Testing for Familial Hypercholesterolemia in a Pediatric Group: A Romanian Showcase

Familial hypercholesterolemia (FH) is a genetic disease marked by high levels of LDL-cholesterol. This condition has long-term clinical implications, such as cardiovascular events, that are evident during adult life. Here, we report on a single-center cross-sectional showcase study of genetic testing for FH in a Romanian pediatric group. Genetic testing for FH was performed on 20 Romanian pediatric patients, 10 boys and 10 girls, admitted with LDL-cholesterol levels over 130 mg/mL to the National Institute for Mother and Child Health "Alesssandrescu-Rusescu" in 2020. Genetic testing was performed using the Illumina TruSight Cardio panel. We identified pathogenic/likely pathogenic variants that could explain the phenotype in 5/20 cases. The involved genes were LDLR and APOB. Clinical signs that suggest the diagnosis of FH are scarce for the pediatric patient, although it can be diagnosed early during childhood by lipid panel screening. Prevention could prove lifesaving for some of these patients.

Familial Hypercholesterolaemia as a Predisposing Factor for Atherosclerosis

Lipid metabolism alterations are an important component of the pathogenesis of atherosclerosis. However, it is now clear that the atherogenesis process involves more than one mechanism, and more than one condition can predispose this condition. Multiple risk factors contribute to the atherosclerosis initiation and define its course. Familial hypercholesterolaemia is a disorder of lipid metabolism that often leads to atherosclerosis development. As is clear from the disease name, the hallmark is the increased levels of low-density lipoprotein cholesterol (LDL-C) in blood. This creates favourable conditions for atherogenesis. In this review, we briefly described the familial hypercholesterolaemia and summarized data on the relationship between familial hypercholesterolaemia and atherosclerosis.

Clinical Aspects of Genetic and Non-Genetic Cardiovascular Risk Factors in Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is the most common monogenic metabolic disorder characterized by considerably elevated low-density lipoprotein cholesterol (LDL-C) levels leading to enhanced atherogenesis, early cardiovascular disease (CVD), and premature death. However, the wide phenotypic heterogeneity in FH makes the cardiovascular risk prediction challenging in clinical practice to determine optimal therapeutic strategy. Beyond the lifetime LDL-C vascular accumulation, other genetic and non-genetic risk factors might exacerbate CVD development. Besides the most frequent variants of three genes (LDL-R, APOB, and PCSK9) in some proband variants of other genes implicated in lipid metabolism and atherogenesis are responsible for FH phenotype. Furthermore, non-genetic factors, including traditional cardiovascular risk factors, metabolic and endocrine disorders might also worsen risk profile. Although some were extensively studied previously, others, such as common endocrine disorders including thyroid disorders or polycystic ovary syndrome are not widely evaluated in FH. In this review, we summarize the most important genetic and non-genetic factors that might affect the risk prediction and therapeutic strategy in FH through the eyes of clinicians focusing on disorders that might not be in the center of FH research. The review highlights the complexity of FH care and the need of an interdisciplinary attitude to find the best therapeutic approach in FH patients.

Nutraceutical Concepts and Dextrin-Based Delivery Systems

Nutraceuticals are bioactive or chemical compounds acclaimed for their valuable biological activities and health-promoting effects. The global community is faced with many health concerns such as cancers, cardiovascular and neurodegenerative diseases, diabetes, arthritis, osteoporosis, etc. The effect of nutraceuticals is similar to pharmaceuticals, even though the term nutraceutical has no regulatory definition. The usage of nutraceuticals, to prevent and treat the aforementioned diseases, is limited by several features such as poor water solubility, low bioavailability, low stability, low permeability, low efficacy, etc. These downsides can be overcome by the application of the field of nanotechnology manipulating the properties and structures of materials at the nanometer scale. In this review, the linear and cyclic dextrin, formed during the enzymatic degradation of starch, are highlighted as highly promising nanomaterials- based drug delivery systems. The modified cyclic dextrin, cyclodextrin (CD)-based nanosponges (NSs), are well-known delivery systems of several nutraceuticals such as quercetin, curcumin, resveratrol, thyme essential oil, melatonin, and appear as a more advanced drug delivery system than modified linear dextrin. CD-based NSs prolong and control the nutraceuticals release, and display higher biocompatibility, stability, and solubility of poorly water-soluble nutraceuticals than the CD-inclusion complexes, or uncomplexed nutraceuticals. In addition, the well-explored CD-based NSs pathways, as drug delivery systems, are described. Although important progress is made in drug delivery, all the findings will serve as a source for the use of CD-based nanosystems for nutraceutical delivery. To sum up, our review introduces the extensive literature about the nutraceutical concepts, synthesis, characterization, and applications of the CD-based nano delivery systems that will further contribute to the nutraceutical delivery with more potent nanosystems based on linear dextrins.

Comorbidities with Familial Hypercholesterolemia (FH): A Systematic Review

Familial hypercholesterolemia (FH) is linked to high levels of low-density lipoprotein cholesterol (LDL-C), atherosclerotic, and aortic stenosis to a lesser extent. We looked at the incidence of prevalent comorbid disorders other than cardiovascular disease (CVD), such as diabetes, chronic kidney disease (CKD), hypertension, and cancer in heterozygous FH (HeFH) patients. PubMed, Web of Science, and Google Scholar were searched systematically for studies reporting comorbidities in FH patients. Finally, 23 studies were included after excluding duplicates, papers with unrelated titles, reviews, abstracts, and papers with not sufficient data. Results showed that among the comorbidities that have been studied; FH patients had a greater prevalence of CKD. In terms of diabetes, the data are inconsistent, with some research indicating a higher prevalence of diabetes in FH patients and mostly indicating the opposite. Polymorphism study showed that hypertension has been linked to FH; however, the prevalence of the hypertensive subjects varies among FH groups. In comparison to the general population, cancer was found to have a lower or similar prevalence in FH patients. More research is needed in this area due to the variability of the results of the relationship between diabetes and FH and the small number of studies on cancer. In conclusion only CKD can be considered as an important and prevalent comorbidity in FH population after CVDs.

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.

Treatment of Hypertriglyceridemia: A Review of Therapies in the Pipeline

BackgroundThe 2018 American College of Cardiology/American Heart Association (ACC/AHA) guidelines and 2021 ACC Expert Consensus Decision Pathway recommend nonpharmacological interventions and initiation of statin therapy for patients with moderate hypertriglyceridemia and addition of fibrates or omega-3 fatty acids in severe hypertriglyceridemia. Although the association between triglyceride (TG) lowering and atherosclerotic cardiovascular disease (ASCVD) risk reduction remains controversial, patients with hypertriglyceridemia may represent a subgroup that require additional therapy to further reduce residual ASCVD risk. Moreover, medications that target novel pathways could provide alternative options for patients who are intolerant of existing therapies or doses needed to provide adequate triglyceride lowering. Objective: Assess recent evidence for TG-lowering agents including omega-3 fatty acid-based therapies, PPARα modulators, apoC-III mRNA antisense inhibitors, angiopoietin-like 3 (ANGPTL3) antibodies, and herbal supplements. Methods: A literature search was performed using PubMed with hypertriglyceridemia specified as a MeSH term or included in the title or abstract of the article along with each individual agent. For inclusion, trials needed to have a primary or secondary outcome of TG levels or TG lowering. Conclusion: Currently, the only US Food and Drug Administration approved medication for CV risk reduction in patients with hypertriglyceridemia is icosapent ethyl. Results from phase 3 trials for CaPre, pemafibrate, and volanesorsen as well as additional evidence for pipeline pharmacotherapies with novel mechanisms of action (e.g., ApoC-III mRNA antisense inhibitors and ANGPTL3 antibodies) will help to guide future pharmacotherapy considerations for patients with hypertriglyceridemia.

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.

Familial Hypercholesterolemia (FH) Registry Worldwide: A Systematic Review

Familial hypercholesterolemia (FH) is the most common genetic disease which accelerates the development of premature coronary artery disease (CAD) in young adults if remains untreated. The overall prevalence of FH is currently unknown and is usually underdiagnosed and undertreated worldwide. FH registry in different geographical area is a mission that helps early diagnosis of FH patients in the general population. PubMed, ISI Web of Science, Scopus, and Google Scholar were searched systematically for studies and reports on the FH registry using related keywords. Finally, 27 studies were included in this review. Most of the studies used the CASCADE screening method based on 1 or more than 1 of the 3 well-established FH criteria namely, the Dutch Lipid Clinic Network, Simon Broome Register, or Make Early Diagnosis to Prevent Early Death criteria. Except for a small number of studies that the genetic and molecular methods were used, in other studies only clinical diagnosis was applied. All these studies claimed that the FH registry causes the identification of many new cases as a result of used CASCADE screening and referral to lipid clinics. They concluded that the FH registry increases general and also physician awareness on FH prevalence and its related complications which in the long-term will improve FH management. This indicates that in other parts of the world, the FH registry should be established as well so that more accurate statistics on the prevalence of this disease can be found worldwide which would help in diagnosis and prevention.

Familial hypercholesterolaemia: Experience of a tertiary paediatric lipid clinic

AIM

To review the experience of a dedicated paediatric multidisciplinary lipid clinic in the management of familial hypercholesterolaemia (FH) by studying the demographics, clinical presentations as well as statin therapy and outcomes.

METHODS

Retrospective database review of all patients under 18 years old seen in the lipid clinic at an Australian tertiary paediatric hospital between April 1999 and August 2017. Outcome measures collected included patient demographics, family history, lipid profile, age at treatment commencement, treatment outcomes and complications.

RESULTS

One hundred and eight patients (53 males) were seen in the lipid clinic. Eighty-five had low-density lipoprotein cholesterol (LDL-C) levels at or above the 75th percentile for sex prior to treatment. Of these, 75 had a first-degree relative with hypercholesterolaemia and/or early cardiac death. Four patients had clinical manifestations. Thirty-two patients (14 males) were started on statin therapy for likely FH. LDL-C levels reduced by 2.4 mmol/L (1.4 to 2.7) in boys and 1.9 mmol/L (0.8 to 2.8) in girls at 12 month follow-up. Five patients reported side effects requiring adjustment in therapy. Main reasons for not starting statin therapy in eligible patients were parental refusal and/or lost to follow up (77%).

CONCLUSION

A dedicated multidisciplinary lipid clinic is helpful for streamlining and monitoring management of paediatric FH. Clinical manifestations of FH are rare in children and may represent more severe form of FH or other lipid disorder. Statin therapy is efficacious and well tolerated but current recommended targets of treatment are difficult to attain. Greater awareness and coordinated services are required to overcome poor family engagement.

Adoptive transfer of CX3CR1 transduced-T regulatory cells improves homing to the atherosclerotic plaques and dampens atherosclerosis progression

AIM

Loss of immunosuppressive response supports inflammation during atherosclerosis. We tested whether adoptive cell therapy (ACT) with Tregulatory cells (Tregs), engineered to selectively migrate in the atherosclerotic plaque, would dampen the immune-inflammatory response in the arterial wall in animal models of familial hypercholesterolaemia (FH).

METHODS AND RESULTS

FH patients presented a decreased Treg suppressive function associated to an increased inflammatory burden. A similar phenotype was observed in Ldlr -/- mice accompanied by a selective increased expression of the chemokine CX3CL1 in the aorta but not in other districts (lymph nodes, spleen, and liver). Treg overexpressing CX3CR1 were thus generated (CX3CR1+-Tregs) to drive Tregs selectively to the plaque. CX3CR1+-Tregs were injected (i.v.) in Ldlr -/- fed high-cholesterol diet (western type diet, WTD) for 8 weeks. CX3CR1+-Tregs were detected in the aorta, but not in other tissues, of Ldlr -/- mice 24 h after ACT, corroborating the efficacy of this approach. After 4 additional weeks of WTD, ACT with CX3CR1+-Tregs resulted in reduced plaque progression and lipid deposition, ameliorated plaque stability by increasing collagen and smooth muscle cells content, while decreasing the number of pro-inflammatory macrophages. Shotgun proteomics of the aorta showed a metabolic rewiring in CX3CR1+-Tregs treated Ldlr -/- mice compared to controls that was associated with the improvement of inflammation-resolving pathways and disease progression.

CONCLUSION

ACT with vasculotropic Tregs appears as a promising strategy to selectively target immune activation in the atherosclerotic plaque.

Saudi Familial Hypercholesterolemia Patients With Rare LDLR Stop Gain Variant Showed Variable Clinical Phenotype and Resistance to Multiple Drug Regimen

Familial hypercholesterolemia (FH), a well-known lipid disease caused by inherited genetic defects in cholesterol uptake and metabolism is underdiagnosed in many countries including Saudi Arabia. The present study aims to identify the molecular basis of severe clinical manifestations of FH patients from unrelated Saudi consanguineous families. Two Saudi families with multiple FH patients fulfilling the combined FH diagnostic criteria of Simon Broome Register, and the Dutch Lipid Clinic Network (DLCN) were recruited. LipidSeq, a targeted resequencing panel for monogenic dyslipidemias, was used to identify causative pathogenic mutation in these two families and in 92 unrelated FH cases. Twelve FH patients from two unrelated families were sharing a very rare, pathogenic and founder LDLR stop gain mutation i.e., c.2027delG (p.Gly676Alafs^*33) in both the homozygous or heterozygous states, but not in unrelated patients. Based on the variant zygosity, a marked phenotypic heterogeneity in terms of LDL-C levels, clinical presentations and resistance to anti-lipid treatment regimen (ACE inhibitors, β-blockers, ezetimibe, statins) of the FH patients was observed. This loss-of-function mutation is predicted to alter the free energy dynamics of the transcribed RNA, leading to its instability. Protein structural mapping has predicted that this non-sense mutation eliminates key functional domains in LDLR, which are essential for the receptor recycling and LDL particle binding. In conclusion, by combining genetics and structural bioinformatics approaches, this study identified and characterized a very rare FH causative LDLR pathogenic variant determining both clinical presentation and resistance to anti-lipid drug treatment.

Genetics of Cardiovascular Disease: How Far Are We from Personalized CVD Risk Prediction and Management?

Despite the rapid progress in diagnosis and treatment of cardiovascular disease (CVD), this disease remains a major cause of mortality and morbidity. Recent progress over the last two decades in the field of molecular genetics, especially with new tools such as genome-wide association studies, has helped to identify new genes and their variants, which can be used for calculations of risk, prediction of treatment efficacy, or detection of subjects prone to drug side effects. Although the use of genetic risk scores further improves CVD prediction, the significance is not unambiguous, and some subjects at risk remain undetected. Further research directions should focus on the "second level" of genetic information, namely, regulatory molecules (miRNAs) and epigenetic changes, predominantly DNA methylation and gene-environment interactions.

Severe Hypertriglyceridemia-Induced Acute Pancreatitis

The prevalence of familial hypercholesterolemia (FH) is about 1 in 200–500 in the general population, but approximately less than 1% of those affected are actually diagnosed. One of the most promising approaches to treat FH is utilizing human monoclonal antibodies. This is a case study describing a 47-year-old male patient who presented to the Emergency Department with acute abdominal pain caused by severe hypertriglyceridemia (HTG)-induced acute pancreatitis (AP). We report the steps necessary for establishing the right diagnosis and the management of HTG-induced AP, which are inevitable for the reduction of severity and mortality. This case study shows that hypercholesterolemia is an underdiagnosed and potentially lethal disease. Once diagnosed, all measures should be considered to control blood cholesterol and lipid levels. The decision to administer PCSK9 inhibitors should not be solely based on economical calculation, but rather individual factors should also be considered to weigh the risk/benefit ratio.

The prevalence of hypercholesterolemia and associated risk factors in Al-Kharj population, Saudi Arabia: a cross-sectional survey

Background

Hypercholesterolemia (HC) is an important precursor to many cardiovascular, cerebrovascular, and peripheral vascular diseases. A report conducted by the American Heart Association showed the prevalence of HC to be 11.9%, with around 28.5 million adults age ≥ 20 years having high cholesterol levels. This study aimed to evaluate the prevalence of HC and its associated risk factors among the general population of Al-Kharj, Saudi Arabia.

Method

A cross-sectional study was conducted on the general population of Al-Kharj, Saudi Arabia in 2016. The representative sample consisted of 1019 individuals, who all participated on a voluntary basis. The statistical analysis was performed using SPSS version 25.

Results

The results of this study showed the prevalence of HC in the sample to be 12.5%. There was a significant moderate positive association between increasing age and the prevalence of HC (r = 0.240, P < 0.0001). Males had a significantly higher prevalence of HC (56.7%) compared to their female counterparts (43.3%) (X² = 23.093, P ≤ 0.0001). BMI was positively and significantly associated with high cholesterol status. Participants in the overweight category had a significantly higher risk of HC (OR = 1.727; 95% CI = 1.58–1.914; P = 0.046). The non-obese (< 25 kg/m²) participants had an inverse significant association with the risk of hypercholesterolemia. (OR = 0.411; 95% CI = 0.216–0.783; P = 0.007).

Conclusion

In this population-based study, the predominant risk factors of HC in Al-Kharj region were being of a Saudi nationality, male, having obesity, being unemployed, and being a civilian worker. There is a clear need for future screening studies of HC, as most previous studies have reported contradictory prevalence data (because they were conducted in different regions of KSA). Furthermore, well-designed prospective cohort studies are needed in the future to assess how the association between lifestyle behavioural factors such as dietary intake patterns and levels of physical activity may affect the relative risk of HC status.

A Review of the Efficacy and Tolerability of Bempedoic Acid in the Treatment of Hypercholesterolemia

Despite the widespread use of statins and ezetimibe to decrease low-density lipoprotein cholesterol (LDL-C) levels and associated atherosclerotic cardiovascular disease (ASCVD), many patients do not achieve adequate LDL-C lowering as per the recommended American College of Cardiology (ACC)/American Heart Association (AHA) and European Society of Cardiology (ESC)/European Atherosclerosis Society (EAS) guidelines and demonstrate residual cardiovascular risk. The introduction of proprotein convertase subtilisin/kexin type 9 (PCSK-9) inhibitors in 2015 was a promising addition to hypercholesterolemia therapies, but their cost and subcutaneous administration has limited their use, and therefore, new affordable and patient friendly treatment strategies are crucial to help reduce ASCVD risk. Bempedoic acid, a drug currently under investigation, is a small molecule that has been shown to upregulate LDL receptors, decrease LDL-C, and reduce atherosclerotic plaque formation in hypercholesterolemic patients. Furthermore, bempedoic acid is a prodrug that becomes activated by an enzyme expressed primarily in the liver, allowing it to avoid the potential myotoxicity associated with statin therapy. The purpose of this review is to summarize the major clinical studies evaluating bempedoic acid and describe its potential addition to currently approved lipid-lowering therapies.

Molecular diagnosis methods in familial hypercholesterolemia

Familial hypercholesterolemia (FH) is considered the genetic cause of coronary heart disease and ischemic stroke. FH is mainly an autosomal codominant pattern-based disorder and is primarily determined by point mutations within the low-density lipoprotein receptor, apolipoprotein B, and proprotein convertase subtilisin/kexin type 9 genes, causing increased low-density lipoprotein cholesterol levels in the serum of untreated individuals. The accumulation will eventually lead to atherosclerotic cardiovascular disease. Although clinical criteria comprising several prognosis scores, such as the Simon Broome, Dutch Lipid Clinic Network, Make Early Diagnosis to Prevent Early Death, and the recently proposed Montreal-FH-SCORE, are the conventional basis of diagnosing FH, the genetic diagnosis made by single nucleotide polymorphism genotyping, multiplex ligation-dependent probe amplification analysis, and sequencing (both Sanger and Next-Generation sequencing) offers unequivocal diagnosis. Given the heterogeneity of known mutations, the genetic diagnosis of FH is often difficult to establish, despite the growing evidence of the causative mutations, as well as the polygenic aspect of this pathology and the importance of cascade screening of the FH patient’s healthy family members. This review article details different genetic techniques that can be used in FH identification when there is a clinical FH suspicion based on criteria comprised in prognosis scores, knowing that none of these are exhaustive in the diagnosis, yet they efficaciously overlap and complement each other for confirming the disease at the molecular level.

Homozygous familial hypercholesterolemia with an update on cholesterol management

Familial hypercholesterolemia (FH) is an autosomal dominant condition that increases the risk of premature cardiovascular disease. Despite advances in treatment, it remains under detected and under treated. As an inherited condition, it poses a risk to the patient and family members. Most cases are due to defective low-density lipoprotein receptor (LDLR) activity. Heterozygous mutations are common (1:250-1:300). Homozygous FH is very rare (2-3 in a million), with higher circulating cholesterol levels and a poorer cardiovascular prognosis. We present the management of a case of homozygous hypercholesterolemia due to homozygous LDLR mutation. The patient subsequently developed severe coronary artery and aortic valve disease despite aggressive lipid-lowering therapy. We review advanced lipid management options that include lipoprotein apheresis, Proprotein Convertase Subtilisin/Kexin type 9 inhibition, and the microsomal triglyceride transfer protein inhibitor lomitapide.

[CME: Primary and Secondary Hypercholesterolemia]

CME: Primary and Secondary Hypercholesterolemia Abstract. In patients with hypercholesterolemia and an LDL-cholesterol level >5 mmol/l, familial hypercholesterolemia (primary hypercholesterolemia) should be considered. This genetically determined illness should lead to medical therapy and screening for hypercholesterinemia in close relatives. Beside the superelevated LDL-cholesterol levels, additional clinically diagnostic findings and family anamnesis can support the diagnosis of familial hypercholesterolemia. The likelihood of familial hypercholesterolemia can be estimated using the Lipid Clinic Network Score. Additionally, a variety of exogenous factors may have an impact on lipoprotein metabolism and may lead to secondary hypercholesterolemia. Hypothyroidism, cholestasis, nephrotic syndrome or specific medications, among others, should be considered as potential factors leading to high cholesterol levels before familial hypercholesterolemia is suspected or lipid-lowering treatment is started.

Familial hypercholesterolemia: is it time to separate monogenic from polygenic familial hypercholesterolemia?

PURPOSE OF REVIEW

This review explores the concepts of monogenic and the so-called polygenic familial hypercholesterolemia and how the identification of familial hypercholesterolemia as a monogenic condition and its separation from polygenic primary hypercholesterolemia may have implications for clinical practice.

RECENT FINDINGS

Through genetic testing, a mutation in any of the three known autosomal dominant familial hypercholesterolemia-causing genes is found in 60-80% of cases with a clinical diagnosis of definite familial hypercholesterolemia. As individuals with a polygenic basis for their hypercholesterolemia do not follow the same inheritance pattern observed in monogenic familial hypercholesterolemia, the use of family-based cascade screening in individuals with a polygenic origin is not recommend, as only 30% of relatives have an elevated LDL-C compared to the 50% in monogenic families. The presence of a causative monogenic mutation associates the highest cardiovascular risk vs. not having a mutation or having a polygenic background, providing prognostic information independent of LDL-C. It may also help assess intensity of interventions. Treatment adherence also seems to be higher after monogenic confirmation of hypercholesterolemia.

SUMMARY

Knowledge about the genetic status of an individual with clinical familial hypercholesterolemia (monogenic vs. polygenic) can provide a more informed understanding to evaluating risk, managing disease and opportunities for screening strategies.

Serum lipids and risk of atherosclerosis in xanthelasma palpebrarum: A systematic review and meta-analysis

BACKGROUND

The association between dyslipidemia and xanthelasma palpebrarum (XP) remains controversial, and no definite evidence has indicated atherosclerosis risk in patients with XP.

OBJECTIVE

The present study was a systematic review and meta-analysis to elucidate the association of serum lipid profiles and risk of atherosclerotic diseases with XP.

METHODS

We systematically searched for the eligible comparative studies published before April 15, 2019, in the databases of PubMed, Web of Science, Embase, and Cochrane Library. A random-effects model was used to calculate the standard mean difference with 95% confidence interval for each pooled estimate.

RESULTS

The qualitative analyses included 15 case-control studies with 854 patients with XP. Compared with the controls, the patients with XP had significantly higher serum levels of total cholesterol and low-density lipoproteins, significantly higher apolipoprotein B levels, and relatively lower apolipoprotein A1 levels, and the carotid intima-media thickness was significantly higher.

CONCLUSION

Patients with XP had significantly higher serum levels of atherogenic low-density lipoproteins and bore significantly higher risk of atherosclerosis than the controls. Careful monitoring and targeted intervention for prevention of cardiovascular diseases is essential for these patients.

An interspecies study of lipid profiles and atherosclerosis in familial hypercholesterolemia animal models with low-density lipoprotein receptor deficiency

Small rodents, especially mice and rats, have been widely used in atherosclerosis studies even though humans exhibit completely different lipoprotein metabolism and atherosclerotic characteristics. Until recently, various rodent models of human familial hypercholesterolemia (FH) have been created, including mice, rats, and golden Syrian hamsters. Although hamsters reportedly possess metabolic features similar to humans, there is no systematic characterization of the properties of circulating lipids and atherosclerotic lesions in these rodent models. We used three FH animal species (mice, rats, and hamsters) with low-density lipoprotein receptor (Ldlr) deficiency to fully assess lipoprotein metabolism and atherosclerotic characteristics. Compared to chow diet-fed mice and rats, Ldlr knockout (KO) hamsters showed increased cholesterols in LDL fractions similar to human FH patients. Upon 12-week high-cholesterol/high-fat diet feeding, both heterozygous and homozygous Ldlr KO hamsters displayed hyperlipidemic phenotypes, whereas only homozygous Ldlr KO mice and rats showed only moderate increases in plasma lipid levels. Moreover, rats were resistant to diet-induced atherosclerosis compared to mice, and hamsters showed more atherosclerotic lesions in the aortas and coronary arteries. Further morphological study revealed that only hamsters developed atherosclerosis in the abdominal segments, which is highly similar to FH patients. This unique animal model will provide insight into the translational study of human atherosclerosis and could be useful for developing novel treatments for FH patients.