Generation of two familial hypercholesterolemia patient-specific induced pluripotent stem cell lines harboring heterozygous mutations in the LDLR gene.

Familial hypercholesterolemia (FH) is a genetic disorder affecting the metabolism of lipoprotein, characterized by elevated levels of plasma concentrations of low-density lipoprotein cholesterol (LDLC). The most common FH cause is mutations within the gene that encodes for the LDL receptor (LDLR) protein. Two induced pluripotent stem cell (iPSC) lines were generated from patients with FH, each carrying a single heterozygous mutation in the LDLR gene, one is a missense mutation, c.631C > T, and the other is a splice-site mutation, c.313 + 1G > A. Both iPSC lines exhibited strong expression of pluripotency markers, demonstrated the ability to differentiate into derivatives of the three germ layers, and maintained normal karyotypes. These derived iPSC lines represent powerful tools for in vitro modeling FH and offer a promising platform for therapeutic development.

Human In Vitro Oxidized Low-Density Lipoprotein (oxLDL) Increases Urinary Albumin Excretion in Rats.

Hypercholesterolemia-associated oxidative stress increases the formation of oxidized low-density lipoprotein (oxLDL), which can affect endothelial cell function and potentially contribute to renal dysfunction, as reflected by changes in urinary protein excretion. This study aimed to investigate the impact of exogenous oxLDL on urinary excretion of albumin and nephrin. LDL was isolated from a patient with familial hypercholesterolemia (FH) undergoing lipoprotein apheresis (LA) and was oxidized in vitro with Cu (II) ions. Biochemical markers of LDL oxidation, such as TBARS, conjugated dienes, and free ε-amino groups, were measured. Wistar rats were treated with a single intraperitoneal injection of PBS, LDL, or oxLDL (4 mg of protein/kg b.w.). Urine was collected one day before and two days after the injection. We measured blood lipid profiles, urinary protein excretion (specifically albumin and nephrin), and markers of systemic oxidative stress (8-OHdG and 8-iso-PGF2α). The results showed that injection of oxLDL increased urinary albumin excretion by approximately 28% (310 ± 27 µg/24 h vs. 396 ± 26 µg/24 h, p = 0.0003) but had no effect on nephrin excretion. Neither PBS nor LDL had any effect on urinary albumin or nephrin excretion. Additionally, oxLDL did not affect systemic oxidative stress. In conclusion, hypercholesterolemia may adversely affect renal function through oxidatively modified LDL, which interferes with the renal handling of albumin and leads to the development of albuminuria.

Lipoprotein(a) is associated with DNA damage in patients with heterozygous familial hypercholesterolemia.

Heterozygous familial hypercholesterolemia (HeFH) is a common autosomal-dominant inherited disorder associated with atherosclerotic cardiovascular disease (ASCVD). HeFH subjects have a higher lipoprotein(a), i.e. Lp(a), concentration than the general population. Patients with FH are exposed to elevated levels of LDL from birth and ox-LDL may induce other oxidation pathways. The aim of the study was to determine the levels of markers of oxidative stress and DNA damage in patients with HeFH and describe the effect of Lp(a) on the resulting damage. Higher DNA damage was identified in patients with HeFH compared to the normolipidemic ones, and ASCVD was associated with greater damage. Oxidative stress markers were elevated in HeFH patients; however, only ox-LDL was higher in the ASCVD group and its level correlated with DNA damage. A positive correlation was found between DNA damage and Lp(a) concentration in the HeFH patients. Higher levels of Lp(a) were associated with greater DNA damage, especially in patients with HeFH and ASCVD. In HeFH patients, the optimal Lp(a) cut-off point associated with ASCVD is > 23.45 nmol/L, i.e. much lower than for the general population; however this cut-off point needs validation in a larger group of HeFH patients.

An integration-free iPSC line ZZUNEUi029-A derived from peripheral blood mononuclear cells of a patient with familial hypercholesterolemia carrying a mutation in LDLR gene.

Familial hypercholesterolemia is a hereditary disorder that causes severely elevated low-density lipoprotein levels, which can lead to an increased risk for premature cardiovascular disease. Mutations in the LDLR gene are the most common cause of familial hypercholesterolemia. In this study, we report the generation of ZZUNEUi029-A, a human induced pluripotent stem cell line (hiPSC) from a male patient with c. 622 G â†’ A in LDLR gene using non-integrative Sendai viral reprogramming technology. This cell line expressed pluripotency markers, had a normal male karyotype (46XY) and maintained the ability to differentiate into the three germ layers in vitro.

Improved extracellular vesicle-based mRNA delivery for familial hypercholesterolemia treatment.

Extracellular vesicle (EV)-based low-density lipoprotein receptor (Ldlr) mRNA delivery showed excellent therapeutic effects in treating familial hypercholesterolemia (FH). Nevertheless, the loading inefficiency of EV-based mRNA delivery presents a significant challenge. Recently, RNA-binding proteins (RBPs) have been fused to EV membrane proteins for selectively encapsulating targeted RNAs to promote loading efficiency. However, the strong interaction between therapeutic RNAs and RBPs prevents RNA release from endosomes to the cytosol in the recipient cells. In this study, an improved strategy was developed for efficient encapsulation of Ldlr mRNA into EVs in donor cells and controllable release in recipient cells. Methods: The MS2 bacteriophage coat protein (CD9-MCP) fusion protein, Ldlr mRNA, and a customized MS2 containing RNA aptamer base-pair matched with Ldlr mRNA were expressed in donor cells. Cells receiving the above therapeutic EVs were simultaneously treated with EVs containing "Ldlr releaser" with a sequence similar to the recognition sites in Ldlr mRNA. Therapeutic effects were analyzed in Ldlr-/- mice receiving EV treatments via the tail vein. Results: In vitro experiments demonstrated improved loading efficiency of Ldlr mRNA in EVs via MS2-MCP interaction. Treatment of "Ldlr releaser" competitively interacted with MS2 aptamer with higher affinity and released Ldlr mRNA from CD9-MCP for efficient translation. When the combinatory EVs were delivered into recipient hepatocytes, the robust LDLR expression afforded therapeutic benefits in Ldlr-/- mice. Conclusion: We proposed an EV-based mRNA delivery strategy for enhanced encapsulation of therapeutic mRNAs in EVs and RNA release into the cytosol for translation in recipient cells with great potential for gene therapy.

"All-in-One" Exosome Engineering Strategy for Effective Therapy of Familial Hypercholesterolemia.

Exosomes serve as a promising therapeutic nanoplatform. However, the exosomes produced by donor cells are a heterogeneous group, with only a small portion having high therapeutic efficacy. Specific isolation of the subpopulation with high efficacy is important for lowering the dose and minimizing toxicity. In this study, we loaded target mRNA and displayed specific Flag in engineered exosomes simultaneously. Briefly, the donor cells were transfected with plasmid expressing a fusion protein Flag-TCS-PTGFRN-CTSL-MCP, namely, exosome sorter. During biogenesis, the RNA-binding motif MCP can specifically bind with MS2-containing RNA and sort the target RNA into the lumen of exosomes. Anti-Flag magnetic beads can capture and thus purify the engineered exosomes via recognition of the Flag on the surface of exosomes. After purification, the Flag could be cleaved by thrombin treatment while MCP can be separated from the fusion protein by CTSL autocleavage upon exosome acidification, minimizing the side effects and augmenting the therapeutic effects. By the proof-of-concept experiment, the exosome sorter-based "all-in-one" strategy was confirmed effective in both the encapsulation of therapeutic mRNA (Ldlr-MS2) into exosomes and the subsequent purification. The purified Ldlr-MS2-containing exosomes had much higher efficacy in alleviating atherosclerosis, in comparison with the bulk exosomes, confirming the advantage of the proposed "all-in-one" strategy.

APOE Molecular Spectrum in a French Cohort with Primary Dyslipidemia.

Primary hypercholesterolemia is characterized by elevated LDL-cholesterol (LDL-C) levels isolated in autosomal dominant hypercholesterolemia (ADH) or associated with elevated triglyceride levels in familial combined hyperlipidemia (FCHL). Rare APOE variants are known in ADH and FCHL. We explored the APOE molecular spectrum in a French ADH/FCHL cohort of 5743 unrelated probands. The sequencing of LDLR, PCSK9, APOB, and APOE revealed 76 carriers of a rare APOE variant, with no mutation in LDLR, PCSK9, or APOB. Among the 31 APOE variants identified here, 15 are described in ADH, 10 in FCHL, and 6 in both probands. Five were previously reported with dyslipidemia and 26 are novel, including 12 missense, 5 synonymous, 2 intronic, and 7 variants in regulatory regions. Sixteen variants were predicted as pathogenic or likely pathogenic, and their carriers had significantly lower polygenic risk scores (wPRS) than carriers of predicted benign variants. We observed no correlation between LDL-C levels and wPRS, suggesting a major effect of APOE variants. Carriers of p.Leu167del were associated with a severe phenotype. The analysis of 11 probands suggests that carriers of an APOE variant respond better to statins than carriers of a LDLR mutation. Altogether, we show that the APOE variants account for a significant contribution to ADH and FCHL.

Latest clinical evidence about the effect of PCSK9 monoclonal antibodies in patients with familial hypercholesterolaemia: an updated meta-analysis.

INTRODUCTION: Familial hypercholesterolaemia (FH) is the most common autosomal genetic disease of cholesterol metabolism disorder. Proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibody (mAb) is a new target lipid-regulating drug related to cholesterol metabolism that has been developed in recent years. The reported rate of reduction varies widely, and comprehensive assessments of efficacy and safety are lacking. Therefore, we conducted this study to investigate the clinical effect of PCSK9 mAbs in patients with familial hypercholesterolaemia to provide a theoretical reference for clinical practice. MATERIAL AND METHODS: We analysed the clinical data of patients, including the percentage change in LDL-C and the incidence rates of treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs), from selected articles. Weighted mean differences (WMDs), risk ratios (RRs), and 95% confidence intervals (95% CIs) were calculated to compare the endpoints. RESULTS: The results showed that, compared with placebo, the PCSK9 mAb reduced the percentage change in LDL-C in FH patients (WMD = -45.52, 95% CI: -49.70 to -41.34, I2 = 99.6%). In addition, there was no significant difference between the experimental and placebo groups in the incidence of TEAEs (RR = 1.03, 95% CI: 0.97 to 1.10, I2 = 19.1%) and SAEs (RR = 1.02, 95% CI: 0.72 to 1.44, I2 = 0.0%). CONCLUSIONS: Overall, PSCK9 mAbs are an effective and safe method of LDL-C reduction in patients with FH.

The microsomal triglyceride transfer protein inhibitor lomitapide improves vascular function in mice with obesity.

OBJECTIVE: In this study, the effect of lomitapide, a microsomal triglyceride transfer protein inhibitor, on the cardiovascular function in obesity was investigated. METHODS: Eight-week-old C57BL/6 mice were fed with high-fat diet for 12 weeks in the presence and absence of lomitapide. Lomitapide was administered by gavage (1 mg/kg/d) during the last 2 weeks of high-fat feeding. Body weight, blood glucose, body composition, and lipid profile were determined. Vascular function and endothelial function markers were studied in the aorta and mesenteric resistance arteries. RESULTS: Lomitapide treatment reduced body weight in mice with obesity. Blood glucose, percentage of fat mass, total cholesterol, and low-density lipoprotein levels were significantly reduced, and the percentage of lean mass was significantly increased after lomitapide treatment. The vascular response to sodium nitroprusside in the aorta and mesenteric arteries was similar among groups. However, the vascular response to acetylcholine was improved in the treated group. This was associated with decreased levels of vascular endoplasmic reticulum stress, inflammation, and oxidative stress. CONCLUSIONS: Treatment with lomitapide attenuated the increase in body weight in mice with obesity and restored the lipid profile and vascular function. These effects were accompanied by a decrease in inflammation and oxidative stress.

Induced pluripotent stem cell line ICGi038-A, obtained by reprogramming peripheral blood mononuclear cells from a patient with familial hypercholesterolemia due to compound heterozygous c.1246C > T/c.940 + 3_940 + 6del mutations in LDLR.

The development of cellular models for familial hypercholesterolemia (FH) is an important direction for creating new approaches to atherosclerosis treatment. Pathogenic mutations in the LDLR gene are the main FH source. We generated an iPSC line from peripheral blood mononuclear cells of the patient with compound heterozygous c.1246C > T/c.940 + 3_940 + 6del LDLR mutation. The resulting iPSC line with confirmed patient-specific mutations maintains a normal karyotype and a typical undifferentiated state, including morphology, pluripotent gene expression, and in vitro differentiation potential. This iPSC line can be further differentiated toward relevant cells to better understand FH pathogenesis.

A novel low-density lipoprotein receptor variant in a Ukrainian patient: a case report and overview of the disease-causing low-density lipoprotein receptor variants associated to familial hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH) is characterized by high low-density lipoprotein-cholesterol levels and it is primarily caused by pathogenic/likely pathogenic variants (P/LPVs) in LDLR, APOB or PCSK9 genes. Next generation sequencing (NGS) technology allows the evaluation of more genes simultaneously, rising the diagnostic throughput of genomics laboratories. MATERIALS AND METHODS: We report a Ukrainian 37-year-old woman hypercholesterolemic since 2010. Despite a suggestive family history, FH was suspected only when the patient referred to the Endocrine and Metabolic Diseases Center of the Fondazione Policlinico Universitario A. Gemelli IRCCS in Rome. After specialist advice, genetic testing was offered to the patient at our Molecular and Genomic Diagnostics Unit. RESULTS: A targeted NGS-based pipeline highlighted a novel out-of-frame deletion in the LDLR gene. This variant has a clear deleterious effect on the LDLR protein and it can be classified as PV. CONCLUSIONS: The ideal model of care for FH is an evidence-based system aimed to provide the highest-quality health services to all FH patients. In fact, this study reports that the integrated care pathway adopted in our hospital for FH patients led successfully to the discovery of a novel LDLR PV in an Ukrainian patient. The finding of this LDLR variant allowed the clinical FH diagnosis in this patient and in her family, expanding the knowledge of FH-related genetic variants in the Ukrainian population.

A Systematic Approach to Assess the Activity and Classification of PCSK9 Variants.

BACKGROUND: Gain of function (GOF) mutations of PCSK9 cause autosomal dominant familial hypercholesterolemia as they reduce the abundance of LDL receptor (LDLR) more efficiently than wild-type PCSK9. In contrast, PCSK9 loss of function (LOF) variants are associated with a hypocholesterolemic phenotype. Dozens of PCSK9 variants have been reported, but most remain of unknown significance since their characterization has not been conducted. OBJECTIVE: Our aim was to make the most comprehensive assessment of PCSK9 variants and to determine the simplest approach for the classification of these variants. METHODS: The expression, maturation, secretion, and activity of nine well-established PCSK9 variants were assessed in transiently transfected HEK293 cells by Western blot and flow cytometry. Their extracellular activities were determined in HepG2 cells incubated with the purified recombinant PCSK9 variants. Their binding affinities toward the LDLR were determined by solid-phase immunoassay. RESULTS: LDLR expression increased when cells were transfected with LOF variants and reduced when cells were transfected with GOF variants compared with wild-type PCSK9. Extracellular activities measurements yielded exactly similar results. GOF and LOF variants had increased, respectively reduced, affinities for the LDLR compared with wild-type PCSK9 with the exception of one GOF variant (R218S) that showed complete resistance to inactivation by furin. All variants were expressed at similar levels and underwent normal maturation and secretion patterns except for two LOF and two GOF mutants. CONCLUSIONS: We propose that transient transfections of HEK293 cells with a plasmid encoding a PCSK9 variant followed by LDLR expression assessment by flow cytometry is sufficient to reliably determine its GOF or LOF status. More refined experiments should only be used to determine the underlying mechanism(s) at hand.

Refinement of pathogenicity classification of variants associated with familial hypercholesterolemia: Implications for clinical diagnosis.

BACKGROUND: The lack of functional evidence for most variants detected during the molecular screening of patients with clinical familial hypercholesterolemia (FH) makes the definitive diagnosis difficult. METHODS: A total of 552 variants in LDLR, APOB, PCSK9 and LDLRAP1 genes found in 449 mutation-positive FH (FH/M+) patients were considered. Pathogenicity update was performed following the American College of Medical Genetics and Genomics (ACMG) guidelines with additional specifications on copy number variants, functional studies, in silico prediction and co-segregation criteria for LDLR, APOB and PCSK9 genes. Pathogenicity of LDLRAP1 variants was updated by using ACMG criteria with no change to original scoring. RESULTS: After reclassification, the proportion of FH/M+ carriers of pathogenic (P) or likely pathogenic (LP) variants, and FH/M+ carriers of likely benign (LB) or benign (B) variants, was higher than that defined by standard criteria (81.5% vs. 79.7% and 7.1% vs. 2.7%). The refinement of pathogenicity classification also reduced the percentage of FH with variants of uncertain significance (VUS) (17.7% vs. 11.4%). After adjustment, the FH diagnosis by refined criteria best predicted LDL-C levels (Padj <0.001). Notably, FH with VUS variants had higher LDL-C than those with LB (all Padj ≤ 0.033), but similar to those with LP variants. CONCLUSION: Accurate variant interpretation best predicts the increase of LDL-C levels and shows its clinical utility in the molecular diagnosis of FH.

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

OBJECTIVES: The aim of this study was to provide the first study to systematically analyze the efficacy and safety of PCSK9-mAbs in the treatment of familial hypercholesterolemia (FH). METHODS: A computer was used to search the electronic Cochrane Library, PubMed/MEDLINE, and Embase databases for clinical trials using the following search terms: "AMG 145", "evolocumab", "SAR236553/REGN727", "alirocumab", "RG7652", "LY3015014", "RN316/bococizumab", "PCSK9", and "familial hypercholesterolemia" up to November 2020. Study quality was assessed with the Cochrane Collaboration's tool, and publication bias was evaluated by a contour-enhanced funnel plot and the Harbord modification of the Egger test. After obtaining the data, a meta-analysis was performed using R software, version 4.0.3. RESULTS: A meta-analysis was performed on 7 clinical trials (926 total patients). The results showed that PCSK9-mAbs reduced the LDL-C level by the greatest margin, WMD -49.14%, 95% CI: -55.81 to -42.47%, on FH versus control groups. PCSK9-mAbs also significantly reduced lipoprotein (a) (Lp (a)), total cholesterol (TC), triglycerides (TG), apolipoprotein-B (Apo-B), and non-high-density lipoprotein cholesterol (non-HDL-C) levels and increased HDL-C and apolipoprotein-A1 (Apo-A1) levels of beneficial lipoproteins. Moreover, no significant difference was found between PCSK9-mAbs treatment and placebo in common adverse events, serious events, and laboratory adverse events. CONCLUSION: PCSK9-mAbs significantly decreased LDL-C and other lipid levels with satisfactory safety and tolerability in FH treatment.

COVID-19 and lipids. The role of lipid disorders and statin use in the prognosis of patients with SARS-CoV-2 infection.

The global coronavirus disease 2019 (COVID-19) pandemic caused by the SARS-CoV-2 coronavirus started in March 2020. The conclusions from numerous studies indicate that people with comorbidities, such as arterial hypertension, diabetes, obesity, underlying cardiovascular disease, are particularly vulnerable to the severe course of COVID-19. The available data also suggest that patients with dyslipidemia, the most common risk factor of cardiovascular diseases, are also at greater risk of severe course of COVID-19. On the other hand, it has been shown that COVID-19 infection has an influence on lipid profile leading to dyslipidemia, which might require appropriate treatment. Owing to antiviral, anti-inflammatory, immunomodulatory, and cardioprotective activity, statin therapy has been considered as valuable tool to improve COVID-19 outcomes. Numerous observational studies have shown potential beneficial effects of lipid-lowering treatment on the course of COVID-19 with significant improved prognosis and reduced mortality.

Transcatheter aortic valve replacement in a patient with premature coronary artery disease and calcific aortic stenosis complicated by heterozygous familial hypercholesterolemia.

We describe a case of a 59-year-old man with severe heterozygous familial hypercholesterolemia (FH) and elevated lipoprotein(a) presenting with severe aortic stenosis, treated with transcatheter aortic valve replacement (TAVR). His history also includes premature coronary artery disease requiring coronary artery bypass surgery at age 48 and a stroke at age 55. His pre-treatment lipid values include an LDL-Cholesterol (LDL-C) of 458 mg/dL, total cholesterol of 588 mg/dL, and lipoprotein (a) level of 351 nmol/L. Since his FH diagnosis, he has received several lipid-lowering agents including statins, bile acid sequestrants, nicotinic acid derivatives, and PCSK9 inhibitors. This case reflects the association of FH and elevated lipoprotein(a) with aortic stenosis and TAVR as a viable and effective treatment.

Familial Hypercholesterolemia: JACC Focus Seminar 4/4.

Detecting familial hypercholesterolemia (FH) early and "normalizing" low-density lipoprotein (LDL) cholesterol values are the 2 pillars for effective cardiovascular disease prevention in FH. Combining lipid-lowering therapies targeting synergistic/complementary metabolic pathways makes this feasible, even among severe phenotypes. For LDL receptor-dependent treatments, PCSK9 remains the main target for adjunctive therapy to statins and ezetimibe through a variety of approaches. These include protein inhibition (adnectins), inhibition of translation at mRNA level (antisense oligonucleotides or small interfering RNA), and creation of loss-of-function mutations through base-pair editing. For patients with little LDL receptor function, LDL receptor-independent treatment targeting ANGPTL3 through monoclonal therapies are now available, or in the future, antisense/small interfering RNA-based approaches offer alternative approaches. Finally, first-in-human studies are ongoing, testing adenovirus-mediated gene therapy transducing healthy LDLR DNA in patients with HoFH. Further development of the CRISPR cas technology, which has shown promising results in vivo on introducing PCSK9 loss-of-function mutations, will move a single-dose, curative treatment for FH closer.

Familial Hypercholesterolemia in the Arabian Gulf Region: Clinical results of the Gulf FH Registry.

BACKGROUND AND AIMS: Familial hypercholesterolemia (FH) is a common autosomal dominant disorder that can result in premature atherosclerotic cardiovascular disease (ASCVD). Limited data are available worldwide about the prevalence and management of FH. Here, we aimed to estimate the prevalence and management of patients with FH in five Arabian Gulf countries (Saudi Arabia, Oman, United Arab Emirates, Kuwait, and Bahrain). METHODS: The multicentre, multinational Gulf FH registry included adults (≥18 years old) recruited from outpatient clinics in 14 tertiary-care centres across five Arabian Gulf countries over the last five years. The Gulf FH registry had four phases: 1- screening, 2- classification based on the Dutch Lipid Clinic Network, 3- genetic testing, and 4- follow-up. RESULTS: Among 34,366 screened patient records, 3713 patients had suspected FH (mean age: 49±15 years; 52% women) and 306 patients had definite or probable FH. Thus, the estimated FH prevalence was 0.9% (1:112). Treatments included high-intensity statin therapy (34%), ezetimibe (10%), and proprotein convertase subtilisin/kexin type 9 inhibitors (0.4%). Targets for low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol were achieved by 12% and 30%, respectively, of patients at high ASCVD risk, and by 3% and 6%, respectively, of patients at very high ASCVD risk (p <0.001; for both comparisons). CONCLUSIONS: This snap-shot study was the first to show the high estimated prevalence of FH in the Arabian Gulf region (about 3-fold the estimated prevalence worldwide), and is a "call-to-action" for further confirmation in future population studies. The small proportions of patients that achieved target LDL-C values implied that health care policies need to implement nation-wide screening, raise FH awareness, and improve management strategies for FH.

Alternative C3 Complement System: Lipids and Atherosclerosis.

Familial hypercholesterolemia (FH) is increasingly associated with inflammation, a phenotype that persists despite treatment with lipid lowering therapies. The alternative C3 complement system (C3), as a key inflammatory mediator, seems to be involved in the atherosclerotic process; however, the relationship between C3 and lipids during plaque progression remains unknown. The aim of the study was to investigate by a systems biology approach the role of C3 in relation to lipoprotein levels during atherosclerosis (AT) progression and to gain a better understanding on the effects of C3 products on the phenotype and function of human lipid-loaded vascular smooth muscle cells (VSMCs). By mass spectrometry and differential proteomics, we found the extracellular matrix (ECM) of human aortas to be enriched in active components of the C3 complement system, with a significantly different proteomic signature in AT segments. Thus, C3 products were more abundant in AT-ECM than in macroscopically normal segments. Furthermore, circulating C3 levels were significantly elevated in FH patients with subclinical coronary AT, evidenced by computed tomographic angiography. However, no correlation was identified between circulating C3 levels and the increase in plaque burden, indicating a local regulation of the C3 in AT arteries. In cell culture studies of human VSMCs, we evidenced the expression of C3, C3aR (anaphylatoxin receptor) and the integrin αMß2 receptor for C3b/iC3b (RT-PCR and Western blot). C3mRNA was up-regulated in lipid-loaded human VSMCs, and C3 protein significantly increased in cell culture supernatants, indicating that the C3 products in the AT-ECM have a local vessel-wall niche. Interestingly, C3a and iC3b (C3 active fragments) have functional effects on VSMCs, significantly reversing the inhibition of VSMC migration induced by aggregated LDL and stimulating cell spreading, organization of F-actin stress fibers and attachment during the adhesion of lipid-loaded human VSMCs. This study, by using a systems biology approach, identified molecular processes involving the C3 complement system in vascular remodeling and in the progression of advanced human atherosclerotic lesions.

Real-World Efficacy of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors (PCSK9i) in Heterozygous Familial Hypercholesterolemia Patients Referred for Lipoprotein Apheresis.

BACKGROUND A small proportion of familial hypercholesterolemia (FH) patients can adequately control this condition, although achieving the recommended targets for low-density lipoprotein cholesterol (LDL-c) levels remains a challenge. Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) are new and potent lipid-lowering drugs. However, there is scarce literature on real-world data about their use in patients with FH. MATERIAL AND METHODS We examined the reduction in LDL-c levels from the baseline, after PCSK9i initiation in heterozygous familial hypercholesterolemia patients referred for lipoprotein apheresis in our regional lipid clinic. The study was conducted from March 2018 to September 2019, the period immediately after PCSK9i reimbursement was available in France. PCSK9i was added on top of the patients' maximal tolerated lipid-lowering regimens. RESULTS The study had 123 patients with heterozygous FH. The mean age of the patients was 59±11 years. The mean baseline LDL-c for all the participants was 277±78 mg/dl. It was 283±81 mg/dl in the PCSK9i monotherapy group (n=83), 247±68 mg/dl in the PCSK9i plus ezetimibe group (n=12), and 264±78 mg/dl in the PCSK9i plus statin and ezetimibe group (n=28). The mean decrease observed in the LDL-c level from baseline was 136±70 mg/dl (n=123), 125±60 mg/dl (n=83), 103±77 mg/dl (n=12), and 175±70 mg/dl (n=28), respectively. CONCLUSIONS An overall reduction of 49.1% from the baseline LDL-c was observed in the heterozygous FH population after PCSK9i initiation in a real-world experience. The group treated with PCSK9i ezetimibe plus statin showed further reduction of their LDL-c levels with a better responder rate, achieving the target 50% reduction in LDL-c from the baseline.