Old challenges and new opportunities in the clinical management of heterozygous familial hypercholesterolemia (HeFH): The promises of PCSK9 inhibitors

Identifying patients with familial hypercholesterolemia using data mining methods in the Northern Great Plain region of Hungary

BACKGROUND AND AIMS

Familial hypercholesterolemia (FH) is one of the most frequent diseases with monogenic inheritance. Previous data indicated that the heterozygous form occurred in 1:250 people. Based on these reports, around 36,000-40,000 people are estimated to have FH in Hungary, however, there are no exact data about the frequency of the disease in our country. Therefore, we initiated a cooperation with a clinical site partner company that provides modern data mining methods, on the basis of medical and statistical records, and we applied them to two major hospitals in the Northern Great Plain region of Hungary to find patients with a possible diagnosis of FH.

METHODS

Medical records of 1,342,124 patients were included in our study. From the mined data, we calculated Dutch Lipid Clinic Network (DLCN) scores for each patient and grouped them according to the criteria to assess the likelihood of the diagnosis of FH. We also calculated the mean lipid levels before the diagnosis and treatment.

RESULTS

We identified 225 patients with a DLCN score of 6-8 (mean total cholesterol: 9.38 ± 3.0 mmol/L, mean LDL-C: 7.61 ± 2.4 mmol/L), and 11,706 patients with a DLCN score of 3-5 (mean total cholesterol: 7.34 ± 1.2 mmol/L, mean LDL-C: 5.26 ± 0.8 mmol/L).

CONCLUSIONS

The analysis of more regional and country-wide data and more frequent measurements of total cholesterol and LDL-C levels would increase the number of FH cases discovered. Data mining seems to be ideal for filtering and screening of FH in Hungary.

Impact of Age on the Efficacy and Safety of Alirocumab in Patients with Heterozygous Familial Hypercholesterolemia

PURPOSE

This post-hoc analysis examined whether age modified the efficacy and safety of alirocumab, a PCSK9 inhibitor, in patients with heterozygous familial hypercholesterolemia (HeFH), using pooled data from four 78-week placebo-controlled phase 3 trials (ODYSSEY FH I, FH II, LONG TERM, and HIGH FH).

METHODS

Data from 1257 patients with HeFH on maximally tolerated statin ± other lipid-lowering therapies were analyzed by an alirocumab dose regimen and by age subgroups (18 to < 45, 45 to < 55, 55 to < 65, and ≥ 65 years). In the FH I and II trials, patients received 75 mg subcutaneously every 2 weeks (Q2W), with dose increase to 150 mg Q2W at week 12 if week 8 low-density lipoprotein cholesterol (LDL-C) was ≥ 70 mg/dl. In HIGH FH and LONG TERM, patients received 150 mg alirocumab Q2W.

RESULTS

Baseline characteristics were similar between treatment groups across all age groups; the proportion of males decreased whereas the proportion of patients with coronary heart disease, diabetes, hypertension, and declining renal function increased with increasing age. Mean LDL-C reductions at week 24 were consistent across age groups (50.6-61.0% and 51.1-65.8% vs. placebo for the 75/150 and 150 mg alirocumab dose regimens, respectively; both non-significant interaction P-values). Treatment-emergent adverse events occurred in similar frequency in alirocumab- and placebo-treated patients regardless of age, except for injection-site reactions, which were more common in alirocumab than placebo but declined in frequency with age.

CONCLUSIONS

Alirocumab treatment resulted in significant LDL-C reductions at weeks 12 and 24 and was generally well tolerated in patients with HeFH across all age groups studied.

Prevalence and pharmacologic management of familial hypercholesterolemia in an unselected contemporary cohort of patients with stable coronary artery disease

INTRODUCTION

Familial hypercholesterolemia (FH) is an inherited disorder characterized by elevated plasma levels of low-density lipoprotein cholesterol (LDL-C) associated with premature cardiovascular disease.

METHODS

Using the data from the START (STable Coronary Artery Diseases RegisTry) study, a nationwide, prospective survey on patients with stable coronary artery disease (CAD), we described prevalence and lipid lowering strategies commonly employed in these patients. The study population was divided into "definite/probable FH," defined as a Dutch Lipid Clinic Network (DLCN) score ≥6, "possible FH" with DLCN 3-5, and "unlikely FH" in presence of a DLCN <3.

RESULTS

Among the 4030 patients with the DLCN score available, 132 (3.3%) were classified as FH (2.3% with definite/probable and 1.0% with possible FH) and 3898 (96.7%) had unlikely FH. Patients with both definite/probable and possible FH were younger compared to patients not presenting FH. Mean on-treatment LDL-C levels were 107.8 ± 41.5, 84.4 ± 40.9, and 85.8 ± 32.3 (P < 0.0001) and a target of ≤70 mg/dL was reached in 10.9%, 30.0%, and 22.0% (P < 0.0001) of patents with definite/probable, possible FH, and unlikely FH, respectively. Statin therapy was prescribed in 85 (92.4%) patients with definite/probable FH, in 38 (95.0%) with possible FH, and in 3621 (92.9%) with unlikely FH (P = 0.86). The association of statin and ezetimibe, in absence of other lipid-lowering therapy, was more frequently used in patients with definite/probable FH compared to patients without FH (31.5% vs 17.5% vs 9.5%; P < 0.0001).

CONCLUSIONS

In this large cohort of consecutive patients with stable CAD, FH was highly prevalent and generally undertreated with lipid lowering therapies.

Pinostrobin Inhibits Proprotein Convertase Subtilisin/Kexin-type 9 (PCSK9) Gene Expression through the Modulation of FoxO3a Protein in HepG2 Cells

Pinostrobin, a flavonoid phytochemical found in variety of plants, has been demonstrated to possess numerous bioactivities such as antioxidant, anti-inflammatory, anticancer, and neuroprotective properties. The aim of this study was to investigate the hypocholesterolemic effect of pinostrobin on the regulation of the gene expression of PCSK9 and its underlying mechanisms in hepatic cells. We found that pinostrobin (20 and 40 μM) significantly inhibited the PCSK9 promoter activity from 1.00 ± 0.16 (fold) to 0.85 ± 0.06 and 0.54 ± 0.05, respectively, as well as the suppression of PCSK9 mRNA expression from 1.00 ± 0.11 (fold) to 0.81 ± 0.07 and 0.58 ± 0.07, respectively, in HepG2 cells. Pinostrobin significantly reduced the mature form of the PCSK9 protein, inhibited the catalytic activity of PCSK9, and increased the protein level of LDLR and the LDL uptake activity in HepG2 cells. We further demonstrated that pinostrobin markedly increased the level of nuclear forkhead box O3a (FoxO3a) protein, enhanced FoxO3a/PCSK9 promoter complexes formation, and attenuated the promoter binding capacity of nuclear HNF-1α. The knockdown of FoxO3a in HepG2 cells by small interference RNA (siRNA) abolished the pinostrobin-mediated PCSK9 reduction. Finally, we demonstrated that pinostrobin attenuated simvastatin-induced PCSK9 overexpression in HepG2 cells. Our current findings reveal that pinostrobin is a PCSK9 inhibitor and down-regulates the PCSK9 gene expression through the up-regulation of the FoxO3a level in hepatic cells. Pinostrobin with potential PCSK9 inhibitory activity may serve as a novel agent for cholesterol regulation and lipid management.

Population specific genetic heterogeneity of familial hypercholesterolemia in South Africa

PURPOSE OF REVIEW

To describe the prevalence and population-specific genetic heterogeneity of familial hypercholesterolemia in South Africa.

RECENT FINDINGS

This review highlights the paucity of data on familial hypercholesterolemia in South Africa, and the urgent need to uncover the mutation profiles in lipid-associated genes, causing an increase in LDL-cholesterol in the different ethnic groups. Case reports and small studies have shown that familial hypercholesterolemia, although apparently uncommon, is present in black Africans.

SUMMARY

Local founder effects have led to an increased prevalence of familial hypercholesterolemia in several South African populations: Afrikaner founder mutations (c.681 C>G, c.1285 G>A, c.523 G>A), Ashkenazi founder mutation (c.654_656del) and possible Indian founder mutation (c.2054 C>T). Preliminary data in black Africans with elevated LDL-cholesterol identified a possible common mutation, c.137_142del. The South African multiethnic society and well described founder effects emphasize the need for differential approaches to diagnosis and management of familial hypercholesterolemia. Studies involving larger cohorts and inclusive of different ethnicities are paramount to establishing an accurate prevalence of familial hypercholesterolemia in black Africans, not only in South Africa but in the Sub-Saharan African region. It is clear that the estimated world prevalence of one in 250 cannot be generally applied across African populations.

Molecular diagnosis of familial hypercholesterolaemia

PURPOSE OF REVIEW

Familial hypercholesterolaemia is a hereditary disorder of lipoprotein metabolism which causes a lifelong increase in LDL-C levels resulting in premature coronary heart disease. The present review looks at some of the recent literature on how molecular methods can be used to assist in the definitive diagnosis of familial hypercholesterolaemia in a range of patient groups.

RECENT FINDINGS

Several recent studies have shown that the prevalence of clinical familial hypercholesterolaemia is higher than previously thought at 1/200 to 1/300, and that 2-5% of patients presenting with early myocardial infarction can be found to have a familial hypercholesterolaemia mutation. The present review then examines different approaches to molecular testing for familial hypercholesterolaemia including point mutation panels versus next-generation sequencing gene panels, and the range of genes tested by some of those panels. Finally, we review the recent evidence for polygenic hypercholesterolaemia within clinically defined familial hypercholesterolaemia patient populations.

SUMMARY

To identify patients with familial hypercholesterolaemia within clinically selected patient groups efficiently, a clinical scoring system should be combined with a molecular testing approach for mutations and for polygenic LDL-C single-nucleotide polymorphisms. Alternatively, a population screening methodology may be appropriate, using mutation testing at an early age before significant atherosclerosis has begun. The precise molecular testing method chosen may depend on the clinical presentation of the patient, and/or the population from which they arise.