Novel Approaches for the Treatment of Familial Hypercholesterolemia: Current Status and Future Challenges

Design of lipid nanoparticle (LNP) containing genetic material CRISPR/Cas9 for familial hypercholesterolemia

Familial hypercholesterolemia is a genetic disorder caused by mutations in the low- density lipoprotein receptor gene (LDLR) and the current treatment still focuses on symptom management. The aim of this study was to develop a lipid nanoparticle (LNP)- based delivery system for the CRISPR/Cas9 component in correcting LDLR gene mutations. LNPs were prepared using an ultrasonic-solvent emulsification technique by varying the surfactant: oil ratio (SOR), homogenization speed and time, and sonication time. Next, the LNP surface was modified by adding DSPE-PEG2000-NH2 and polyethyleneimine. The next stage is to design the single guide RNA (sgRNA) and Donor DNA wildtype (Donor DNA wt). This genetic material was complexed with LNP and then transfected into Hepa1-6 LDLR mt cells, an in vitro representation of cells suffering from familial hypercholesterolemia. This optimization process produced LNPs with a particle size of 118.6 ± 0.8  nm and a polydispersity index of 0.34 ± 0.03. The LNP surface modification resulted in a zeta potential of +7.5  mV. A transmission electron microscope (TEM) analysis showed spherical morphology with size distribution following a regular pattern. LNP cell viability tests showed good biocompatibility at concentrations <15  mM with a half-maximal inhibitory concentration (IC50) value of 27.7  mM. The dominant cellular uptake mechanism of LNP was through the clathrin-mediated endocytosis (CME) pathway. The Hepa1-6 LDLR mt cell model was successfully produced with the transfecting agent Lipofectamine 3000 by homology-directed repair (HDR) mechanism. The LNP-genetic material complex with a ratio of sgRNA:Cas9:Donor DNA wt (1:1:0.04) showed an increase in LDLR gene expression of 3.3 ± 0.2 times and LDLR protein levels reached 12.95 ± 0.25  ng/mL on day 4 after transfection. The results of this study indicate that the developed LNP-based delivery system has the potential for gene therapy applications in familial hypercholesterolemia.

Familial Hypercholesterolemia: A Comprehensive Review of Advances in Treatment Strategies and the Role of Patient Beliefs

Familial hypercholesterolemia (FH) constitutes the most common inherited lipid disorder caused by mutations in any of the genes involved in the metabolism of low-density lipoprotein (LDL), including the LDL receptor (LDLR), Apolipoprotein B (APOB), or Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9). FH causes increased LDL-cholesterol levels, leading to an increased risk for premature atherosclerotic cardiovascular disease. This comprehensive review aims to discuss the progress of FH management, from classic statin therapy to relatively new therapies such as PCSK9 inhibitors and emerging gene-editing technologies like CRISPR. Furthermore, the article focuses on psychosocial aspects of adherence, such as patient beliefs, cultural influences, and healthcare access, and their impact on treatment outcomes. By examining these emerging treatment approaches, this review aims to create a broader understanding of FH management, focusing on better patient care and reducing the global burden of this condition.

Ferritin-based disruptor nanoparticles: A novel strategy to enhance LDL cholesterol clearance via multivalent inhibition of PCSK9-LDL receptor interaction

Hypercholesterolemia, characterized by elevated low-density lipoprotein (LDL) cholesterol levels, is a significant risk factor for cardiovascular disease. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a crucial role in cholesterol metabolism by regulating LDL receptor degradation, making it a therapeutic target for mitigating hypercholesterolemia-associated risks. In this context, we aimed to engineer human H ferritin as a scaffold to present 24 copies of a PCSK9-targeting domain. The rationale behind this protein nanoparticle design was to disrupt the PCSK9-LDL receptor interaction, thereby attenuating the PCSK9-mediated impairment of LDL cholesterol clearance. The N-terminal sequence of human H ferritin was engineered to incorporate a 13-amino acid linear peptide (Pep2-8), which was previously identified as the smallest PCSK9 inhibitor. Exploiting the quaternary structure of ferritin, engineered nanoparticles were designed to display 24 copies of the targeting peptide on their surface, enabling a multivalent binding effect. Extensive biochemical characterization confirmed precise control over nanoparticle size and morphology, alongside robust PCSK9-binding affinity (KD in the high picomolar range). Subsequent efficacy assessments employing the HepG2 liver cell line demonstrated the ability of engineered ferritin's ability to disrupt PCSK9-LDL receptor interaction, thereby promoting LDL receptor recycling on cell surfaces and consequently enhancing LDL uptake. Our findings highlight the potential of ferritin-based platforms as versatile tools for targeting PCSK9 in the management of hypercholesterolemia. This study not only contributes to the advancement of ferritin-based therapeutics but also offers valuable insights into novel strategies for treating cardiovascular diseases.

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.

Old age as a risk factor for liver diseases: Modern therapeutic approaches

Recent scientific interest has been directed towards age-related diseases, driven by the significant increase in global life expectancy and the growing population of individuals aged 65 and above. The ageing process encompasses various biological, physiological, environmental, psychological, behavioural, and social changes, leading to an augmented susceptibility to chronic illnesses. Cardiovascular, neurological, musculoskeletal, liver and oncological diseases are prevalent in the elderly. Moreover, ageing individuals demonstrate reduced regenerative capacity and decreased tolerance towards therapeutic interventions, including organ transplantation. Liver diseases, such as non-alcoholic fatty liver disease, alcoholic liver disease, hepatitis, fibrosis, and cirrhosis, have emerged as significant public health concerns. Paradoxically, these conditions remain underestimated despite their substantial global impact. Age-related factors are closely associated with the severity and unfavorable prognosis of various liver diseases, warranting further investigation to enhance clinical management and develop novel therapeutic strategies. This comprehensive review focuses specifically on age-related liver diseases, their treatment strategies, and contemporary practices. It provides a detailed account of the global burden, types, molecular mechanisms, and epigenetic alterations underlying these liver pathologies.

Recent Advances in Gene Therapy for Familial Hypercholesterolemia: An Update Review

(1) Background: Existing lipid-lowering therapies have difficulty in achieving lipid target levels in patients with familial hypercholesterolemia (FH), especially in the treatment of patients with homozygous familial hypercholesterolemia. (2) Method: All of the literature data containing "Familial hypercholesterolemia" and "Gene Therapy" in PubMed and Clinical Trials from 2018 to 2022 were selected. (3) Results: The rapid development of gene therapy technology in recent years is expected to change the treatment status of FH patients. As emerging gene therapy vectors, the optimized adeno-associated viruses, exosomes, and lipid nanoparticles have demonstrated an improved safety and higher transfection efficiency. Various RNA-targeted therapies are in phase 1-3 clinical trials, such as small interfering RNA-based drugs inclisiran, ARO-ANG3, ARO-APOC3, olpasiran, SLN360, and antisense oligonucleotide-based drugs AZD8233, vupanorsen, volanesorsen, IONIS-APO(a)Rx, etc., all of which have demonstrated excellent lipid-lowering effects. With gene editing technologies, such as CRISPR-Cas 9 and meganuclease, completing animal experiments in mice or cynomolgus monkeys and demonstrating lasting lipid-lowering effects, patients with FH are expected to reach a permanent cure in the future. (4) Conclusion: Gene therapy is being widely used for the lipid-lowering treatment of FH patients and has shown excellent therapeutic promise, but the current delivery efficiency, economic burden, immunogenicity and the precision of gene therapy can be further optimized.

New Trends and Therapies for Familial Hypercholesterolemia

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

Regulatory Non-Coding RNAs in Familial Hypercholesterolemia, Theranostic Applications

Familial hypercholesterolemia (FH) is a common monogenic disease which is associated with high serum levels of low-density lipoprotein cholesterol (LDL-C) and leads to atherosclerosis and cardiovascular disease (CVD). Early diagnosis and effective treatment strategy can significantly improve prognosis. Recently, non-coding RNAs (ncRNAs) have emerged as novel biomarkers for the diagnosis and innovative targets for therapeutics. Non-coding RNAs have essential roles in the regulation of LDL-C homeostasis, suggesting that manipulation and regulating ncRNAs could be a promising theranostic approach to ameliorate clinical complications of FH, particularly cardiovascular disease. In this review, we briefly discussed the mechanisms and pathophysiology of FH and novel therapeutic strategies for the treatment of FH. Moreover, the theranostic effects of different non-coding RNAs for the treatment and diagnosis of FH were highlighted. Finally, the advantages and disadvantages of ncRNA-based therapies vs. conventional therapies were discussed.

Evaluation of miRNA-27a/b expression in patients with familial hypercholesterolemia

Introduction

We aimed to evaluate the serum level of miRNA-27 expression in patients with familial hypercholesterolemia (FH).

Material and methods

miRNA-27a/b levels in serum were compared between 39 patients with heterozygous FH (HeFH = 20) and homozygous FH (HoFH = 19), and 20 healthy subjects (control group). The expression level of miRNA-27a/b was measured using real-time PCR.

Results

miRNA-27a/b expression in heFH patients (fold change: 2.21 ±0.69, p = 0.001) and in the subgroup of hoFH (fold change: 3 ±1.19, p = 0.001) was significantly higher compared to healthy people. In the comparison between HoFH and HeFH, the HoFH group had a significantly higher level of miRNA-27a/b expression (FC: 1.84 ±1.19, p = 0.009).

Conclusions

We observed higher miRNA-27a/b expression in patients with FH than in healthy individuals. In comparison with HoFH and HeFH groups, the former had a higher expression level of miRNA-27a/b, which indicates the potential of miRNA-27a/b as a candidate marker for the severity of disease in individuals with FH.

Cellular and Molecular Aspects of Managing Familial Hypercholesterolemia: Recent and Emerging Therapeutic Approaches

Familial hypercholesterolemia (FH) as a high-frequency genetic disorder is diagnosed based on family and/or patient's history of coronary heart disease (CHD) or some other atherosclerotic disease, LDL-C levels and/or clinical signs such as tendonous xantomata, arcus cornealis before age 45 years as well as functional mutation in the LDLR, apoB or PCSK9 gene. Its clinical features are detectable since early childhood. Early diagnosis and timely treatment increase life expectancy in most patients with FH. Current FH therapies decrease the level of low-density lipoprotein up to ≥50% from baseline with diet, pharmacotherapeutic treatment, lipid apheresis, and liver transplantation. The cornerstone of medical therapy is the use of more potent statins in higher doses, to which often ezetimibe has to be added, but some FH patients do not achieve the target LDL-C with this therapy Therefore, besides these and the most recent but already established therapeutic approaches including PCSK9 inhibitors, inclisiran, and bempedoic acid, new therapies are on the horizon such as gene therapy, CRISPR/Cas9 strategy etc. This paper focuses on cellular and molecular potential strategies for the treatment of FH.

Integrated analysis of microRNA and mRNA expression profiles in homozygous familial hypercholesterolemia patients and validation of atherosclerosis associated critical regulatory network

Homozygous familial hypercholesterolemia (HoFH) is a rare, life-threatening genetic disorder characterized by an extremely elevated serum level of low-density lipoprotein cholesterol (LDL-C) and accelerated premature atherosclerotic cardiovascular diseases (ASCVD). However, the detailed mechanism of how the pathogenic mutations of HoFH trigger the acceleration of ASCVD is not well understood. Therefore, we performed high-throughput RNA and small RNA sequencing on the peripheral blood RNA samples of six HoFH patients and three healthy controls. The gene and miRNA expression differences were analyzed, and seven miRNAs and six corresponding genes were screened out through regulatory network analysis. Validation through quantitative PCR of genes and miRNAs from 52 HoFH patients and 20 healthy controls revealed that the expression levels of hsa-miR-486-3p, hsa-miR-941, and BIRC5 were significantly upregulated in HoFH, while ID1, PLA2G4C, and CACNA2D2 were downregulated. Spearman correlation analysis found that the levels of ID1, hsa-miR-941, and hsa-miR-486-3p were significantly correlated with additional ASCVD risk factors in HoFH patients. This study represents the first integrated analysis of transcriptome and miRNA expression profiles in patients with HoFH, a rare disease, and as a result, six differentially expressed miRNAs/genes that may be related to atherosclerosis in HoFH are reported. The miRNA-mRNA regulatory network may be the critical regulation mechanism by which ASCVD is accelerated in HoFH.

Atorvastatin Increases the Expression of Long Non-Coding RNAs ARSR and CHROME in Hypercholesterolemic Patients: A Pilot Study

Atorvastatin is extensively used to treat hypercholesterolemia. However, the wide interindividual variability observed in response to this drug still needs further elucidation. Nowadays, the biology of long non-coding RNAs (lncRNAs) is better understood, and some of these molecules have been related to cholesterol metabolism. Therefore, they could provide additional information on variability in response to statins. The objective of this research was to evaluate the effect of atorvastatin on three lncRNAs (lncRNA ARSR: Activated in renal cell carcinoma (RCC) with sunitinib resistance, ENST00000424980; lncRNA LASER: lipid associated single nucleotide polymorphism locus, ENSG00000237937; and lncRNA CHROME: cholesterol homeostasis regulator of miRNA expression, ENSG00000223960) associated with genes involved in cholesterol metabolism as predictors of lipid-lowering therapy performance. Twenty hypercholesterolemic patients were treated for four weeks with atorvastatin (20 mg/day). The lipid profile was determined before and after drug administration using conventional assays. The expression of lncRNAs was assessed in peripheral blood samples by RT-qPCR. As expected, atorvastatin improved the lipid profile, decreasing total cholesterol, LDL-C, and the TC/HDL-C ratio (p < 0.0001) while increasing the expression of lncRNAs ARSR and CHROME (p < 0.0001) upon completion of treatment. LASER did not show significant differences among the groups (p = 0.50). Our results indicate that atorvastatin modulates the expression of cholesterol-related lncRNAs differentially, suggesting that these molecules play a role in the variability of response to this drug; however, additional studies are needed to disclose the implication of this differential regulation on statin response.

Case Report: Cardiac Surgery and Combined Lipid-Lowering Drug Therapy for Homozygous Familial Hypercholesterolemia

Homozygous familial hypercholesterolemia (HoFH) is a rare, autosomal dominant, hereditary, metabolic disease. HoFH patients exhibit severe coronary stenosis and valvular disease, which may result in sudden death, even during adolescence. The challenges faced during surgery and the poor curative effect of conventional lipid-lowering therapy create a treatment bottleneck. We report a rare case of HoFH in a 12-years-old boy with acute myocardial infarction, severe mitral insufficiency, and moderate aortic insufficiency. Coronary artery bypass grafting and valvuloplasty resulted in improved heart function. Postoperative combined lipid-lowering drug therapy was able to reduce low-density lipoprotein cholesterol level from 15.37 mm/L to 6.41 mmol/L. Thus, the combination of medical and surgical treatment was considered effective and can be used to inform treatment guidelines for HoFH with severe complications.