Avaliação do perfil de metilação dos genes LDLR, PCSK9, LDLRAP1 em pacientes portadores de hipercolesterolemia familial / Evaluation of the methylation profile of LDLR, PCSK9, LDLRAP1 genes in patients with familial hypercholesterolemia

As variabilidades genotípicas que determinam algumas alterações fenotípicas e metabólicas podem ter seu diagnostico falho se baseado apenas nos dados genômicos. Na hipercolesterolemia familial (HF) pode-se observar que os dados de variantes nos genes da LDLR, PCSK9, APOB e LDLRAP1 sugeridos pelos consensos atuais para confirmar o diagnóstico, tem mostrado serem insuficientes, mostrando baixa porcentagem de confirmação, mesmo nos dos casos em que características fenotípicas apresentam dados sugestivos importantes. A complementação no auxílio diagnóstico com dados epigenéticos tem sido sugerida em muitas doenças, principalmente nas crônicos degenerativos. A metilação do DNA pode estar envolvida no mecanismo que regulam vários processos metabólicos, entre os quais os envolvidos na expressão de proteínas e neste estudo os que estão envolvidos no metabolismo do colesterol, que poderia explicar fenótipos hipercolesterolemicos sem demonstração clara de variantes nos genes de consenso. O objetivo do presente estudo foi comparar o perfil de metilação dos genes LDLR, PCSK9 e LDLRAP1 entre pacientes com diagnóstico de Hipercolesterolemia Familial confirmado através de variantes genéticas descritas na literatura e pacientes sem diagnóstico confirmado. Além da comparação com indíviduos normolipidêmicos. A seleção dos indivíduos foi realizada na Seção de Dislipidemia do Instituto Dante Pazzanese de Cardiologia (IDPC), do Departamento de Análises Clínicas e Toxicológicas da Universidade Federal do Rio Grande do Norte (UFRN), da Universidade Estadual de Campinas (UNICAMP) e da Faculdade de Medicina de São José do Rio Preto (FAMERP). Através dos critérios MEDPED foram selecionados 133 pacientes para a realização do sequenciamento de um painel de genes relacionados ao fenótipo de HF e a homeostasia do colesterol a fim de confirmar o diagnóstico. Todos os pacientes tiveram o DNA purificado, que foi submetido ao tratamento com bissulfito, amplificado, purificado, desnaturado e sequenciado no sistema PyroMark Q24. Avaliou-se o perfil de metilação, em sítio CpG dos genes da LDLR, PCSK9 e LDLR AP1. A análise estatística foi realizada utilizando o software SPSS v.19, GraphPad Prism, versão 1.03 e o e o software R. 4.1.0. Os pacientes foram classificados em Grupo I: Pacientes com diagnóstico molecular confirmado pelo estudo fenotípico e genotipico (n=40); Grupo II: Pacientes fenotipicamente determinados como hipercolesterolemico, mas sem diagnóstico molecular confirmado pelo estudo genomico (n=93); Grupo III: indivíduos fenotipicamente determinados normolipidêmicos de acordo com a V Diretriz Brasileira de Dislipidemia (n=23). A análise comparativa entre os grupos I x II e II x III, demonstrou diferença estatísta significativa em 13 sítios CpG do total de 28 sítios CpG analisados nos três genes. Além disso, foi possível concluir que alterações nos sítios CpG presentes no gene LDLR influenciaram na presença de xantomas e arco córneo. Houve correlação positiva entre a idade e perfil de metilação do gene PCSK9, assim como, alterações nos sítios CpG deste gene influenciaram na presença de arco córneo e IAM. Além disso, alterações no sítio CPG presente no gene LDLRAP1 influenciou no desenvolvimento de DAC, IAM e RM, além da presença de xantelasma

The genotypic variabilities that determine some phenotypic and metabolic alterations can be misdiagnosed if based only on genomic data. In familial hypercholesterolemia (FH) it can be observed that the data of variants in the genes of LDLR, PCSK9, APOB and LDLR AP1 suggested by the current consensus to confirm the diagnosis, has shown to be insufficient, showing a low percentage of confirmation, even in the cases in which phenotypic characteristics present important suggestive data. Complementing the diagnostic aid with epigenetic data has been suggested in many diseases, especially in chronic degenerative diseases. DNA methylation may be involved in the mechanisms that regulate several metabolic processes, including those involved in the expression of proteins that ,in this study, are involved in cholesterol metabolism, which could explain hypercholesterolemic phenotypes without a clear demonstration of variants in consensus genes. The aim of the present study was to compare the methylation profile of LDLR, PCSK9 and LDLRAP1 genes between patients with a diagnosis of Familial Hypercholesterolemia confirmed through genetic variants described in the literature and patients without a confirmed diagnosis. In addition to the comparison with normolipidemic individuals. The selection of individuals was carried out at the Dyslipidemia Section of the Instituto Dante Pazzanese de Cardiologia (IDPC), in the Department of Clinical and Toxicological Analyzes of the Federal University of Rio Grande do Norte (UFRN), in the State University of Campinas (UNICAMP) and in the Faculdade of Medicine of São José do Rio Preto (FAMERP). Through the MEDPED criteria, 133 patients were selected to perform the sequencing of a panel of genes related to the FH phenotype and cholesterol homeostasis in order to confirm the diagnosis. All patients had their DNA purified, which were subjected to bisulfite treatment, amplified, purified, denatured and sequenced on the PyroMark Q24 system. The methylation profile in the CpG site of the LDLR, PCSK9 and LDLRAP1 genes were evaluated. Statistical analysis were performed using SPSS v.19 software, GraphPad Prism, version 1.03 and R. 4.1.0 software. Patients were classified into Group I: Patients with a molecular diagnosis confirmed by phenotypic and genotypic studies (n=40); Group II: Patients phenotypically determined to be hypercholesterolemic, but without a molecular diagnosis confirmed by the genomic study (n=93); Group III: phenotypically determined normolipidemic individuals according to the V Brazilian Dyslipidemia Directive (n=23). The comparative analysis between groups I x II and II x III showed a statistically significant difference in 13 CpG sites of the total of 28 CpG sites analyzed in the three genes of the project. Furthermore, it was possible to conclude that alterations in the CpG sites present in the LDLR gene influenced the presence of xanthomas and arc corneum. There was a positive correlation between age and PCSK9 gene methylation profile, as well as changes in the CpG sites of this gene influenced the presence of arc corneum and AMI. In addition, alterations in the site present in the LDLRAP1 gene are influencing the development of CAD, AMI and MR, in addition to the presence of xanthelasma

Molecular mechanism of astragaloside Ⅳ against atherosclerosis by regulating miR-17-5p and PCSK9/VLDLR signal pathway / 中国中药杂志

This study explores the regulatory effect of astragaloside Ⅳ on miR-17-5 p and its downstream proprotein convertase subtillisin/kexin type 9(PCSK9)/very low density lipoprotein receptor(VLDLR) signal pathway, aiming at elucidating the mechanism of astragaloside Ⅳ against atherosclerosis(AS). In cell experiment, oxidized low-density lipoprotein(ox-LDL) was used for endothelial cell injury modeling with vascular smooth muscle cells(VSMCs). Then cells were classified into the model group, miR-17-5 p inhibitor group, blank serum group, and astragaloside Ⅳ-containing serum group based on the invention. Afterward, cell viability and the expression of miR-17-5 p, VLDLR, and PCSK9 mRNA and protein in cells in each group were detected. In animal experiment, 15 C57 BL/6 mice were used as the control group, and 45 ApoE~(-/-) mice were classified into the model group, miR-17-5 p inhibitor group, and astragaloside Ⅳ group, with 15 mice in each group. After 8 weeks of intervention, the peripheral serum levels of interleukin-6(IL-6), interleukin-10(IL-10), and tumor necrosis factor-α(TNF-α), and the expression of miR-17-5 p, VLDLR, and PCSK9 mRNA in the aorta of mice were detected. The pathological changes of mice in each group were observed. According to the cell experiment, VSMC viability in the miR-17-5 p inhibitor group and the astragaloside Ⅳ-containing serum group was higher than that in the model group(P<0.05). The mRNA and protein expression of miR-17-5 p and VLDLR in VSMCs in the miR-17-5 p inhibitor group and the astragaloside Ⅳ-containing serum group was lower than that in the model group(P<0.05), but the mRNA and protein expression of PCSK9 was higher than that in the model group(P<0.05). As for the animal experiment, the levels of IL-6 and TNF-α in the peripheral serum of the miR-17-5 p inhibitor group and the astragaloside Ⅳ group were lower(P<0.05) and the serum level of IL-10 was higher(P<0.05) than that of the model group. The mRNA expression of miR-17-5 p and VLDLR in the aorta in the miR-17-5 p inhibitor group and the astragaloside Ⅳ group was lower(P<0.05), and PCSK9 mRNA expression was higher(P<0.05) than that in the model group. Pathological observation showed mild AS in the miR-17-5 p inhibitor group and the astragaloside Ⅳ group. In summary, astragaloside Ⅳ can prevent the occurrence and development of AS. The mechanism is that it performs targeted regulation of miR-17-5 p, further affecting the PCSK9/VLDLR signal pathway, inhibiting vascular inflammation, and thus alleviating endothelial cell injury.

Identificación de variantes genéticas asociadas a hipercolesterolemia familiar en niños y adolescentes de la Región del Biobío, Chile / Identification of genetic variants associated with familial hypercholesterolemia in Chilean children and adolescents

Background: Familial hypercholesterolemia (FH) is commonly associated with mutations in-LDL receptor (LDLR), apolipoprotein B (APOB) and proprotein convertase subtilisin/kexin type 9 (PCSK9). Aim: To identify genetic variants associated with FH in a population of children and adolescents with hypercholesterolemia or a family history of-demonstrated early CVD. Material and Methods: Clinical and biochemical parameters were evaluated, and nine genes related to FH were sequenced namely LDLR, APOB, PCSK9, LDLRAP1, LIPA, APOE, ABCG5, ABCG8 and STAP1, in 55 children and adolescents aged 1 to 18 years old, from non-consanguineous families. Results: Mutations associated with FH were found in 17 children and adolescents, corresponding to p.Asp47Asn, duplication of exons 13-15 and p.Ser326Cys of the LDLR gene; p.Glu204* and Ile268Met of the APOE gene. Thirteen patients were heterozygous, two homozygous, two compound heterozygous, and one double heterozygous. Conclusions: Children and adolescents carrying mutations associated with FH were found by selective screening, which constitutes the first stage in the identification of genetic variants in our country.

Construction of point mutation rabbits using CRISPR/Cas9 / 浙江大学学报·医学版

To establish a rabbit model of proprotein convertase subtilisin/kexin type9 () point mutation with CRISPR/Cas9 gene editing technique. According to the PubMed gene protein data, the PCSK9 protein functional regions of human and rabbit were analyzed by Blast. The 386S (Ser) amino acid functional region of human gene was homologous to the 485S of rabbit gene. Three small guide RNAs and one single-stranded donor oligonucleotide were designed according to the 485S base substitution position and sequence analysis of rabbit gene. The synthetic small guide RNAs, Cas9 mRNA and single-stranded donor oligonucleotide were co-injected into the cytoplasm of rabbit fertilized eggs and the embryos were transferred into the pregnant rabbits. PCR, TA cloning and off-target analysis were performed on the F0 rabbits to identify whether the PCSK9 mutation was successful. Fifteen F0 rabbits were obtained. The sequencing results showed that one of them was PCSK9 point mutation homozygote and two of them were PCSK9 point mutation heterozygotes, and the mutation could be stably inherited. The rabbit model of PCSK9 point mutation was successfully constructed by CRISPR/Cas9 technique, which provides an animal model for exploring the molecular mechanism of impaired PCSK9 function and developing reliable and effective diagnosis and treatment measures.

The relationship between genotype of familial hypercholesterolemia and the efficacy of PCSK9 inhibitors / 中华心血管病杂志

Objective: This study intends to explore the difference in the efficacy of PCSK9 inhibitors in patients with different FH phenotypes by analyzing the level of blood lipids before and after treatment with PCSK9 inhibitors in patients with familial hypercholesterolemia (FH) with different allele grades. Methods: Patients with FH phenotype, who admitted to Beijing Anzhen Hospital from January 2019 to October 2020, were enrolled. Age, sex and other clinical information were collected from enrolled, and the pathogenic genes were detected by the second generation sequencing technique. The patients were divided into five groups according to the number of alleles involved and the degree of gene damage: single allele-null mutation group, single allele-defect mutation group, multi-allele-null mutation group, multi-allele-defect mutation group and no major pathogenic gene mutation group. The results of blood lipids were collected before medication, 4-6 weeks of intensive statin treatment and one month after combined treatment with PCSK9 inhibitor (PCSK9i). The LDL-C level were compared among groups. ASCVD risk stratification was performed in all patients, and the proportion of LDL-C level reaching the corresponding risk stratification target value of each genotype group after treatment was analyzed. Results: A total of 66 patients with FH phenotype were included, including 47 males (71.2%) and 19 females (28.8%),the mean age was(43.1±13.4 years). There were 7 cases in single allele-null mutation group (10.6%), 25 cases in single allele-defect mutation group (37.9%), 8 cases in multi-allele-null mutation group (12.1%), 18 cases in multi-allele-defect mutation group (27.3%) and 8 cases in no major pathogenic mutation group (12.1%). The degree of LDL-C reduction post combined PCSK9 inhibitor therapy was as follows: single allele mutation group>no major pathogenic mutation group>multi-allele mutation group, general distribution was in the range of 0-90.0%. Two groups of single allele mutation and no major pathogenic mutation group>50.0%>multi-allele mutation group. Under the combined treatment of PCSK9 inhibitors, the further decrease of LDL-C was in the order of single allele mutation group>non-major pathogenic mutant group>multi-allele mutation group. The efficacy of combined therapy on reducing LDL-C at 1 month after treatment decreased with the increase of baseline LDL-C level (r = 0.46, P<0.001) in patients with FH phenotype. In addition, the further decrease of LDL-C level post high-intensity statin therapy combined with PCSK9 inhibitors decreased with the increase of baseline LDL-C levels (r = 0.40, P<0.001). The degree of LDL-C decrease was high and stable by statin combined with PCSK9 inhibitor therapy in single allele mutation group. In the single allele-defect mutant group, the decrease of LDL-C increased with the increase of baseline LDL-C level post intensive statin treatment and combined PCSK9 inhibitor treatment ((r=0.54, P=0.009); r=0.45,P=0.030), and the further decrease of LDL-C level decreased with the increase of baseline LDL-C level in single allele-defect mutant group post combined therapy with PCSK9 inhibitor (r=0.43, P=0.040). The decrease of LDL-C in patients with the multi-allele mutation group varied with different pathogenic gene loci and combinations post combined therapy with PCSK9 inhibitor. There was no significant difference in the level of blood lipids between the group without major pathogenic gene mutation and the group with single allele mutation before and after treatment. The percentage of patients achieving LDL-C goals with different genotypes of phenotypic FH were as follows: single allele mutation group (86.7%), non-major pathogenic mutant group (75.0%) and multi-allele mutation grou (<5.0%). Conclusions: All patients with different FH phenotypes could benefit from the intensive lipid-lowering therapy with statins and PCSK9 inhibitors, however, there are significant differences in the efficacy of lowering LDL-C in Chinese patients with FH phenotype with different molecular etiologies. Therefore, the pathogenic gene analysis may suggest the lipid-lowering effect of PCSK9 inhibitors in patients with FH.

Phenotype of definite familial hypercholesterolemia with negative genetic study in Argentina / Fenotipo de hipercolesterolemia familiar definitivo con estudio genético negativo en Argentina

Abstract Objective: Familial hypercholesterolemia (FH) is a monogenic disease, associated with variants in the LDLR, APOB and PCSK9 genes. The initial diagnosis is based on clinical criteria like the DLCN criteria. A score > 8 points qualifies the patient as "definite" for FH diagnosis. The detection of the presence of a variant in these genes allows carrying out familial cascade screening and better characterizes the patient in terms of prognosis and treatment. Methods: In the context of the FH detection program in Argentina (Da Vinci Study) 246 hypercholesterolemic patients were evaluated, 21 with DLCN score > 8 (definite diagnosis).These patients were studied with next generation sequencing to detect genetic variants, with an extended panel of 23 genes; also they were adding the large rearrangements analysis and a polygenic score of 10 SNP (single nucleotide polymorphism) related to the increase in LDL-c. Results: Of the 21 patients, 10 had variants in LDLR, 1 in APOB with APOE, 1 in LIPC plus elevated polygenic score, and 2 patients showed one deletion and one duplication in LDLR, the later with a variation in LIPA. It is highlighted that 6 of the 21 patients with a score > 8 did not show any genetic alteration. Conclusions: We can conclude that 28% of the patients with definite clinical diagnosis of FH did not show genetic alteration. The possible explanations for this result would be the presence of mutations in new genes, confusing effects of the environment over the genes, the gene-gene interactions, and finally the impossibility of detecting variants with the current available methods.

Resumen Objetivo: La hipercolesterolemia familiar (HF) es una enfermedad monogénica asociada a variantes en los genes RLDL, APOB y PCSK9. El diagnóstico inicial se basa en criterios clínicos, como el de la red de clínica de lípidos holandesa (DLCN). Un puntaje > 8 puntos califica al paciente como "definitivo" para diagnóstico de HF. La identificación de una variante en estos genes permite realizar el cribado en cascada familiar y caracterizar mejor al paciente en cuanto al pronóstico y el tratamiento. Métodos: En el marco del Programa de Detección de HF en Argentina (Estudio Da Vinci) se evaluó a 246 pacientes hipercolesterolémicos, 21 con puntaje DLCN > 8 (diagnóstico definitivo). Se estudió a estos pacientes con secuenciación de próxima generación para reconocer variantes genéticas, con un panel ampliado de 23 genes, sumado al análisis de grandes rearreglos y por último se aplicó un score poligénico de 10 SNP (polimorfismo de nucleótido único) relacionados con aumento del c-LDL. Resultados: De los 21 pacientes, 10 presentaron variantes en RLDL, uno en APOB junto a APOE, uno en LIPC más puntaje poligénico elevado, dos pacientes con una deleción y una duplicación en RLDL y este último caso con una variante en LIPA. Es destacable que 6 de los 21 pacientes con puntaje DLCN > 8 no mostraron ninguna alteración genética. Conclusiones: El 28% de los pacientes con diagnóstico clínico definitivo de HF no evidenció alteración genética. Las posibles explicaciones de este resultado serían la presencia de mutaciones en nuevos genes, los efectos confundidores del ambiente sobre los genes o la interacción gen-gen y por último la imposibilidad de detectar variantes con la metodología actual disponible.

Efficacy and safety of alirocumab versus ezetimibe in high cardiovascular risk Chinese patients with hyperlipidemia: ODYSSEY EAST Study-Chinese sub-population analysis / 中华心血管病杂志

Objective: To compare the efficacy and safety profile of alirocumab (PCSK9 inhibitor) versus ezetimibe on top of maximally tolerated statin dose in high cardiovascular risk Chinese patients with hyperlipidemia. Methods: The ODYSSEY EAST study was a randomized, double-blinded, double dummy, active-control, parallel group, multi-centers clinical trial, the Chinese sub-population included 456 patients with hyperlipidemia and high cardiovascular risk on maximally tolerated statin dose. Patients were randomized (2∶1) to receive the subcutaneous injection of alirocumab (75 mg Q2W; with dose up titration to 150 mg Q2W at week 12 if low-density lipoprotein cholesterol (LDL-C) was ≥1.81 mmol/L at week 8) or the oral administration of ezetimibe (10 mg daily) for 24 weeks. The primary endpoint was percentage change in calculated LDL-C from baseline to week 24. Key secondary efficacy endpoints included percentage change from baseline to week 12 or 24 in LDL-C (week 12) and other lipid parameters, including apolipoprotein (Apo) B, non-high-density lipoprotein cholesterol (non-HDL-C), TC, lipoprotein(a) (Lp(a)), HDL-C, fasting triglycerides (TG), and Apo A1, and the proportion of patients reaching LDL-C<1.81 mmol/L at week 24. Safety profile of therapeutic drugs was also assessed during the treatment period. Results: The mean age of 456 Chinese patients was (59.5±10.9) years, 341(74.8%) patients were male, 303 patients (66.4%) in alirocumab group and 153 patients (33.5%) in ezetimibe group. Demographic characteristics, disease characteristics, and lipid parameters at baseline were similar between the two groups. LDL-C was reduced more from baseline to week 12 and 24 in alirocumab group versus ezetimibe group, the difference of their least-squares mean (standard error) percent change were(-35.2±2.2)% and (-36.9±2.5)% (both P<0.001). At 12 weeks, alirocumab had significant reduction on Lp(a), Apo B, total cholesterol and non HDL-C, the difference of their least-squares mean (standard error) percent change were (-40.3±2.8)%, (-27.7±1.8)%, (-19.6±1.5)% and (-27.7±1.9)%, respectively (all P<0.001). At 24 weeks, the percent of patients who reached LDL-C<1.81 mmol/L and LDL-C<1.42 mmol/L was significantly higher in alirocumab group (85.3% and 70.5%) than in ezetimibe group (42.2% and 17.0%, both P<0.001), and alirocumab use was also associated with significant reduction on Lp(a), Apo B, total cholesterol and non HDL-C, the difference of their least-squares mean (standard error) percent change were (-37.2±2.8)%, (-29.1±2.0)%, (-21.6±1.6)% and (-29.6±2.2)%, respectively (all P<0.001). The incidence of treatment related adverse events was similar between the two treatment groups (223/302 patients (73.8%) in alirocumab group and 109/153 patients (71.2%) in ezetimibe group). Respiratory infection, urinary infection, dizziness and local injection-site reactions were the most frequently reported adverse events. Conclusions: In high cardiovascular risk patients with hyperlipidemia from China on maximally tolerated statin dose, the reduction of LDL-C induced by alirocumab is more significant than that induced by ezetimibe. Both treatments were generally safe during the observation period of study.

The triglyceride-lowering effects of PCSK9 inhibitor differ in patients with different baseline triglyceride levels / 南方医科大学学报

OBJECTIVE@#To investigate the triglyceride (TG)-lowering effects of PCSK9 inhibitor in patients with in different baseline triglyceride levels.@*METHODS@#Between February, 2019 and March, 2020, a total of 59 patients were treated with PCSK9 inhibitor (Evolocumab) in 5 hospitals, including Nanfang Hospital, Guangdong Provincial People's Hospital, First Affiliated Hospital of Sun Yat-sen University, Foshan Nanhai District People's Hospital and Yulin First People's Hospital. According to baseline triglyceride levels, the patients were divided into normal TG group (< 1.70 mmol/L, =24), mild hypertriglyceridemia group (1.70-2.29 mmol/L, =11), moderate hypertriglyceridemia group (2.30-5.63 mmol/L, =13), and severe hypertriglyceridemia group (≥5.64 mmol/L, =11), and the changes in TG level after the treatment were compared among the 4 groups.@*RESULTS@#In the groups with normal and mildly elevated baseline TG level, the patients did not show significant changes in TG levels after the treatment. In patients with moderately and severely elevated baseline TG levels, treatment with PCSK9 inhibitor significantly reduced their TG levels ( < 0.005).@*CONCLUSIONS@#PCSK9 inhibitor has a significant TG-lowering effect in patients with moderate to severe hypertriglyceridemia but not in patients with only mildly elevated baseline TG level.

Elegibilidad para la indicación de inhibidores de PCSK9 según las recomendaciones de diferentes sociedades científicas / Eligibility for the indication of PCSK9 inhibitors according to the recommendations of different scientific societies

La reducción del colesterol-LDL (C-LDL) es un objetivo primordial en prevención cardiovascular. Estudios recientes demostraron beneficio clínico al administrar inhibidores de la proprotein convertase subtilisin/kexin-9 (iPCSK9) a pacientes que no habían logrado la meta de C-LDL con estatinas de alta intensidad y ezetimibe, sin embargo el uso de estos fármacos está limitado por su costo. El American College of Cardiology, la Sociedad Argentina de Cardiología y la European Society of Cardiology recomiendan una meta de C-LDL menor a 70 mg/dl en prevención secundaria, determinando umbrales de C-LDL de 70, 100 o 140 mg/dl respectivamente, para iniciar el tratamiento con iPCSK9. Con el objetivo de evaluar el esquema hipolipemiante prescripto en internados por síndrome coronario agudo o revascularización coronaria y analizar la proporción de elegibles para ser tratados con iPCSK9 en un escenario real y simulado, realizamos un estudio que incluyó 351 pacientes con enfermedad coronaria, tomados de una base de datos electrónica de un hospital universitario. El 48.4% recibió estatinas de elevada intensidad, 11.4% ezetimibe y 54.7% no logró la meta de C-LDL menor a 70 mg/dl. Utilizando un modelo de simulación en el que todos serían medicados con estatinas de elevada intensidad y ezetimibe, la elegibilidad para prescribir iPCSK9 fue de 31.1%, 12.8% y 9.1% según los umbrales de C-LDL determinados por las tres sociedades científicas. Nuestro estudio demostró una brecha entre las recomendaciones de los consensos para reducir el colesterol y la práctica habitual que debería ser minimizada para optimizar la relación costo/efectividad en prevención secundaria.

LDL-cholesterol (LDL-C) lowering is a primary objective in cardiovascular prevention. Recent studies demonstrated clinical benefit when proprotein convertase subtilisin/kexin-9 inhibitors (PCSK9i) were added to the treatment in patients who had not achieved the LDL-C goal despite being treated with high intensity statins and ezetimibe, however the use of these drugs is limited by their cost. The American College of Cardiology, the Argentine Society of Cardiology and the European Society of Cardiology recommend an LDL-C goal less than 70 mg/dl in secondary prevention, determining thresholds of LDL-C to start treatment with PCSK9i of 70, 100 or 140 mg/dl respectively. In order to evaluate the lipid-lowering regimen prescribed in patients hospitalized for acute coronary syndrome or coronary revascularization and analyze the proportion of eligible to be treated with PCSK9i in a real and simulated scenario, we conducted a study that included 351 patients with coronary disease collected from an electronic database of a university hospital. The 48.4% received high intensity statins, 11.4% ezetimibe and 54.7% did not achieve the LDL-C goal of less than 70 mg/dL. Using a simulation model in which all would be treated with high intensity statins and ezetimibe, the eligibility to prescribe PCSK9i was 31.1%, 12.8% and 9.1% according to the C- LDL thresholds determined by the three scientific societies. Our study demonstrated a gap between the consensus recommendations for LDL-C lowering and the current practice that should be minimized to optimize the cost/effectiveness ratio in secondary prevention.

PCSK9 Inhibitors: Clinical Relevance, Molecular Mechanisms, and Safety in Clinical Practice / Inibidores de PCSK9: Importância Clínica, Mecanismos Moleculares, e Segurança na Prática Clínica

Abstract Coronary artery disease (CAD) is one of the leading causes of mortality. High circulating levels of low-density lipoprotein (LDL) in the blood are associated with cardiovascular mortality, whether through an etiological role or through its association with the progression of CAD per se. Randomized clinical trials have shown that, when LDL levels are reduced, cardiovascular risk is also reduced, which reinforces this association. The first major trial involving a hypolipidemic agent of the statin family, the Scandinavian Simvastatin Survival Study (4S), was published in 1994 and found a significant reduction in mortality in patients at high cardiovascular risk. However, even in subsequent studies with different statins, a residual risk persisted, and this seems not to have changed over time; it is speculated that this risk may be due to statin intolerance. In this scenario, the potential exists for novel hypolipidemic agents to drive a true revolution in the therapy of dyslipidemia. The recent discovery of PCSK9 inhibitors (PCSK9i), a class of hypolipidemic monoclonal antibodies, is extremely promising. PCSK9 inhibition is capable of promoting a mean LDL reduction of up to 60%, with potential for very significant clinical repercussions, as every 38 mg/dL reduction in LDL appears to be associated with a 22% reduction in cardiovascular risk. This review addresses a brief history of PCSK9i, major trials of these drugs, cardiovascular outcomes, and aspects related to their efficacy and safety. Finally, the molecular mechanisms and possible pleiotropic effects of PCSK9i are also discussed.

Resumo A doença arterial coronariana (DAC) é uma das principais causas de mortalidade. Níveis circulantes elevados de lipoproteína de baixa densidade (LDL) no sangue estão associados com mortalidade cardiovascular, seja por um papel etiológico ou por sua associação com a progressão da DAC em si. Estudos clínicos randomizados mostram que, quando os níveis de LDL são reduzidos, o risco cardiovascular também é reduzido, o que reforça tal associação. O primeiro ensaio importante envolvendo um agente hipolipemiante da família da estatina, o estudo Scandinavian Simvastatin Survival Study (4S), foi publicado em 1994 e encontrou uma redução significativa na mortalidade de pacientes com risco cardiovascular elevado. Contudo, mesmo em estudos subsequentes com diferentes estatinas, observou-se um risco residual persistente, o qual aparentemente não mudou ao longo dos anos. Especula-se que esse risco se deve à intolerância às estatinas. Nesse cenário, existe um potencial para novos agentes hipolipemiantes que levem a uma verdadeira revolução no tratamento das dislipidemias. A descoberta recente dos inibidores de PCSK9 (PCSK9i), uma classe de anticorpos monoclonais, é extremamente promissora. A inibição da PCSK9 é capaz de promover uma redução média nos níveis de LDL de até 60%, com potencial para repercussões clínicas muito significativas, já que para cada redução de 38 mg/dL, parece haver uma redução de 22% no risco cardiovascular. Esta revisão aborda uma breve história dos PCSK9i, os principais ensaios envolvendo esses medicamentos, desfechos cardiovasculares, e aspectos relacionados a sua eficácia e segurança. Finalmente, os mecanismos moleculares e possíveis efeitos pleiotrópicos dos PCSK9i são também discutidos.

Caracterização funcional in vitro de variantes no gene PCSK9 identificadas em pacientes com Hipercolesterolemia Familial / In vitro functional characterization of PCSK9 variants identified in patients with Familial Hypercholesterolemia

A Hipercolesterolemia Familial (HF) é uma doença genética do metabolismo das lipoproteínas, caracterizada pelo aumento do colesterol plasmático, transportado principalmente pela lipoproteína de baixa densidade (LDL). A HF é causada principalmente por mutações nos genes LDLR, APOB e PCSK9. As mutações conhecidas na PCSK9 podem levar ao aumento ou diminuição da função proteolítica da proteína, as quais são associadas ao aumento ou diminuição da LDL-c plasmática, respectivamente. Com o projeto genoma humano surgiram novos métodos de sequenciamento, o que resultou em um grande número de novas variantes genéticas relacionadas à HF. Entretanto, os mecanismos pelos quais essas variantes influenciam na concentração do colesterol e sua interferência na resposta terapêutica não estão totalmente elucidados. O objetivo do presente trabalho foi avaliar in vitro o efeito de variantes na região codificadora e reguladora do gene PCSK9 identificadas em pacientes HF utilizando sequenciamento de nova geração. Para a caracterização funcional das variantes na região codificadora da PCSK9, primeiramente foi avaliado o impacto dessas variantes na interação PCSK9-LDLR via Docking molecular. Células HEK293FT foram transfectadas com as diferentes construções da PCSK9, e posteriormente, foram utilizadas em ensaios para avaliar a atividade do LDLR e a internalização de LDL por citometria de fluxo. Para as variantes na região reguladora da PCSK9, foi realizado uma predição in silico do possível efeito de variantes na região 3UTR na ligação de miRNAs. A avalição da interação entre os miRNAs preditos, e a região 3UTR da PCSK9, e o possível impacto nessa interação na presença de variantes na região 3UTR, foi realizada em células HEK293FT transfectadas com um plasmídeo contendo a 3UTR da PCSK9 e um gene repórter da Gaussia luciferase, juntamente com um plasmídeo de expressão contendo os miRNAs de interesse. Foi também estudado o efeito dos miRNAs preditos sobre a expressão, RNAm e proteína, da PCSK9 via RT-qPCR e Western blot, em células HepG2. Foram identificadas 9 variantes na região codificadora da PCSK9, e duas, E32K e R469W, foram selecionadas para os ensaios posteriores. Para a R469W foi observada uma possível alteração conformacional a qual poderia aumentar a afinidade da PCSK9 pelo LDLR. Para a E32K, uma possível associação com HF foi observada em uma família brasileira com ascendência japonesa. As variantes E32K e R469W apresentaram uma redução na atividade do LDLR de 5 e 11%, respectivamente em comparação a PCSK9-WT. Entretanto, não foram observadas reduções estaticamente significativas na atividade do LDLR e na internalização da LDL em células transfectadas com ambas as variantes. Dez variantes foram encontradas na região 3UTR da PCSK9, entre elas três foram selecionadas por impactar a ligação de quatro miRNAs. Nossos dados demonstraram uma redução significativa na expressão da PCSK9 em células HepG2 transfectadas com os miR-4721 e miR-564 (p=0,036 e p=0,010, respectivamente). Porém, não foi observada diferenças na expressão da luciferase em células transfectadas com esses miRNAs, não sendo possível validar a interação miRNA-RNAm. As variantes no gene PCSK9 identificadas no nosso estudo podem não explicar individualmente o fenótipo HF, mas podem contribuir para a severidade da doença juntamente com outras variantes em outros genes

Familial Hypercholesterolemia (FH) is a genetic disorder of lipoprotein metabolism, characterized by elevated plasma cholesterol levels, mostly carried by low-density lipoprotein (LDL). FH is mainly caused by mutations in three genes, LDLR, APOB, and PCSK9. Gain-of-function mutations in PCSK9 reduce LDL receptor levels, resulting in high levels of LDL cholesterol in the plasma. Loss-of-function mutations lead to higher levels of the LDL receptor, resulting in lower LDL cholesterol levels. The Human Genome Project led to a faster technological development related to sequencing methods, which allowed identifying many novel variants associated with FH. However, the mechanisms by which these variants influence cholesterol levels and their interference in therapeutic response are not fully understood. The aim of the present study was to perform an in vitro characterization of the effect of PCSK9 variants identified in FH patients using Next-Generation Sequencing. For the functional characterization of variants in the coding region of PCSK9, the impact of these variants on PCSK9-LDLR interaction was evaluated by molecular docking. HEK293FT cells were transiently transfected with different PCSK9 constructs, and the amount of cell surface LDLR and LDL internalization were determined by flow cytometry. For the variants in PCSK9 3UTR region, an in silico prediction of PCSK9 3UTR variants in miRNA seed regions and target sites was performed. To determine whether the predicted miRNAs directly interact with PCSK9 3UTR region, HEK293FT cells were co-transfected with a vector containing a PCSK9 3'UTR region and a Gaussia luciferase reporter gene, together with an expression plasmid containing the miRNAs of interest. The effect of the predicted miRNAs on the expression of PCSK9 was evaluated using RT-qPCR and Western blot in HepG2 cells transiently transfected with miRNA mimics. Nine missense variants were identified in PCSK9 gene. E32K e R469W were chosen for further analysis. For R469W, a possible conformational change was observed that could increase the affinity of PCSK9 for LDLR, when compared to the wild-type. For E32K, a possible association with FH in a Brazilian family with Japanese ancestry was observed. E32K and R469W had a 5% and 11% decreased level of cell surface LDLR, respectively, as compared with WT-PCSK9. However, no significant reduction in the number of cell surface LDLR and LDL internalization was observed in transfected cells for both variants. Ten variants were found in PCSK9 3'UTR region, of which three were selected for affecting the binding of four miRNAs. Our data demonstrated a significant downregulation of PCSK9 in cells transfected with miR-4721 and miR-564 miRNA mimics, compared to cells transfected with a scramble control (p=0,036 and p=0,010, respectively). However, no differences in luciferase expression were observed in cells transfected with these miRNAs, therefore, it was not possible to experimentally validate miRNA-mRNA interaction. PCSK9 variants found in our study may not fully explain FH phenotype but may contribute to the severity of the disease together with other variants in other genes

Ultrassequenciamento exômico dos principais genes relacionados com a hipercolesterolemia familial / Ultrasequensing exomic of the main genes related to familial hypercholesterolemia

A frequência de Hipercolesterolemia Familial (HF) ainda é desconhecida no Brasil, principalmente pela ausência de estudos com caracterização genotípica associada à fenotípica. Os dados epidemiológicos existentes se baseiam apenas no fenótipos e carecem do diagnóstico molecular confirmatório. O objetivo do presente estudo foi identificar as principais causas genéticas da HF em pacientes diagnosticados fenotipicamente através de um painel exômico com 61 genes a fim de contribuir para um sistema de confirmação do diagnostico molecular em uma amostra da população brasileira. Para isso foram incluídos 141 pacientes, não aparentados, portadores de HF atendidos pelo setor de dislipidemias do Instituto Dante Pazzanese de Cardiologia, Laboratório de Analises Clinicas da Faculdade de Ciências Farmacêuticas da Universidade Federal do Rio Grande do Norte e do Programa Hipercol Brasil do Instituto do Coração. As amostras de sangue periférico foram obtidas para determinações fenotípicas laboratoriais e extração de DNA genômico. A biblioteca de DNA foi construída utilizando o kit Nextera® Rapid Capture Enrichment Custom enriquecendo os éxons de 61 genes que direta ou indiretamente estão relacionados com metabolismo do colesterol. O ultrassequenciamento foi realizado utilizando kit MiSeq Reagent (300 a 500 ciclos) na plataforma MiSeq (Illumina). Os resultados de sequenciamento foram inicialmente alinhados a uma sequência referência e analisados para eliminação de falsos positivos, segundo os parâmetros de qualidade, tais como: cobertura mínima de 30x, frequência do alelo alterado maior que 20% e diferença da distribuição das leituras entre as sequências nucleotídicas menor que 15%. Foram identificadas 472 diferentes variantes em 56 dos genes presentes no painel, sendo 45 consideradas como não descritas. Nos genes APOA1, APOA2, LIPC, RBP4 e TIMP1 não foram observadas variantes dentro dos critérios estabelecidos. Das variantes observadas 25 identificadas em 30 (21,2%) pacientes já tinha sido publicadas em relação à HF nos três principais genes (LDLR, APOB e PCSK9), confirmando o diagnóstico. Foi caracterizado genotipicamente outras dislipidemias primárias em 7 pacientes, sem diagnóstico molecular de HF, através de variantes identificadas no ultrassequenciamento em outros genes. Dos 104 pacientes que não possuíam nenhuma variante já previamente caracterizada, 69 possuíam variantes relacionados com o metabolismo do colesterol. As variantes sem patogenicidade conhecida foram avaliadas através de ferramentas de predição in silico e 22 delas possuíam características sugestivas de patogenicidade em pelo menos 4 das ferramentas utilizadas, duas delas também mostraram alterar a estrutura da proteína segundo análises de docking molecular. Foram identificadas também 223 variantes em região não transcritas (UTR). Quando realizada as análises estatística de todas as variantes identificadas, observamos associação de 13 variantes com concentrações mais elevadas de colesterol da LDL, 5 com concentrações mais elevadas de apolipoproteina B-100, 5 com concentrações mais elevadas de colesterol total, 6 com presença de arco córneo, 2 com manifestação de xantelasmas, 2 com ausência de xantomas e 3 com a presença de doença arterial coronariana. Dessas 6 variantes já haviam sido previamente descritas com HF ou algum outro fenótipo associado e 2 não tinham citação na literatura pesquisada, mas possuíam característica patogênica para a proteína segundo as ferramentas de predição in silico. Este estudo permitiu a identificação das causas genéticas da HF em pacientes brasileiros diagnosticados fenotipicamente, mostrando que a técnica escolhida permitiu caracterizar 21,2% dos pacientes. Além disso, foi possível identificar outras dislipidemias primárias e caracterizar algumas variantes que, apesar de necessitarem serem validadas, indicam uma possível associação com a HF, aumentando o esclarecimento do fenótipo com o genótipo para 74,5%. Este estudo também possibilitou a identificação de novas variantes que devem ser avaliadas para confirmar associação com a doença e utilizar para o diagnóstico propondo um novo painel poligênico

The frequency of Familial Hypercholesterolemia (FH) is still unknown in Brazil, mainly due to the absence of studies with genotypic characterization associated with phenotype. Existing epidemiological data are based only on the phenotypes and lack the confirmatory molecular diagnosis. The aim of the present study was to identify main genetic causes of FH in patients diagnosed phenotypically through an exomic panel with 61 genes in order to contribute to a system of confirmation molecular diagnosis in a sample of the Brazilian population. To this end, 141 non-related patients with FH treated by the dyslipidemia sector of the Institute Dante Pazzanese of Cardiology, Clinical Analysis Laboratory of the Faculty of Pharmaceutical Sciences of the University Federal of Rio Grande do Norte and the Hipercol Brazil Program of the Heart Institute. Peripheral blood samples were obtained for laboratory phenotypic determinations and extraction of genomic DNA. The DNA library was constructed using the Nextera® Rapid Capture Enrichment Custom kit, enriching with éxons of 61 genes that are directly or indirectly related to cholesterol metabolism. Ultrasequencing was performed using MiSeq Reagent kit (300 to 500 cycles) on the MiSeq platform (Illumina). The sequencing results were initially aligned to a reference sequence and analyzed for false positive elimination according to quality parameters such as: minimum coverage of 30x, altered allele frequency greater than 20%, and difference in the distribution of reads between sequences nucleotides less than 15%. 472 different variants were identified in 56 of the genes present in the panel, of which 45 were considered not described. In the APOA1, APOA2, LIPC, RBP4 and TIMP1 genes no variants were observed within the established criteria. In 25 of the variants observed presents in 30 (21.2%) patients had already been published in relation to FH in the three main genes (LDLR, APOB and PCSK9), confirming the diagnosis. Other primary dyslipidemias were caracterized genotypically in 7 patients, without molecular diagnosis of HF, through variants identified in ultrasequencing in other genes. Of the 104 patients who did not have any previously characterized variant, 69 had variants related to cholesterol metabolism. The variants without known pathogenicity were evaluated using in silico prediction tools and 22 of them had characteristics suggestive of pathogenicity at least 4 of the tools used, two of them also showed to alter the structure of the protein according to molecular docking analyzes. Were also identified 223 non-transcribed region (UTR) variants. Statistical analysis of all the variants identified showed association of 13 variants with higher concentrations of LDL cholesterol, 5 with higher concentrations of apolipoprotein B-100, 5 with higher concentrations of total cholesterol, 6 with presence of an arc corneal, 2 with manifestation of xanthelasms, 2 with absence of xanthomas and 3 with the presence of coronary artery disease. Of these 6 variants had previously been described with HF or some other associated phenotype and 2 had no citation in the researched literature, but had a pathogenic characteristic for the protein according to in silico prediction tools. This study allowed the identification of the genetic causes of FH in Brazilian patients diagnosed phenotypically, showing that the technique chosen allowed to characterize 21.2% of the patients. In addition, it was possible to identify other primary dyslipidemias and to characterize some variants that, although they need to be validated, indicate a possible association with HF, increasing the clarification of the phenotype with the genotype to 74.5%. This study also allowed the identification of new variants that should be evaluated to confirm association with the disease and to use for the diagnosis proposing a new polygenic panel

PCSK9 inhibitors in the current management of atherosclerosis / Los inhibidores de la PCSK9 en el manejo clínico actualizado de la aterosclerosis

Abstract: The history of proprotein convertase subtilisin/kexin type 9 (PCSK9) in medical science is fascinating and the evolution of knowledge of its function has resulted in new medications of major importance for the cardiovascular (CV) patient. PCSK9 functions as a negative control or feedback for the cell surface receptors for low-density lipoprotein including its component of cholesterol (LDL-C). The initial and key findings were that different abnormalities of PCSK9 can result in an increase or a decrease of LDL-C because of more or less suppression of cell surface receptors. These observations gave hints and awoke interest that it might be possible to prepare monoclonal antibodies to PCSK9 and decrease its activity, after which there should be more active LDL-C cell receptors. The rest is a fascinating story that currently has resulted in two PCSK9 inhibitors, alirocumab and evolocumab, which, on average, decrease LDL-C approximately 50%. Nevertheless, if there are no contraindications, statins remain the standard of prevention for the high-risk CV patient and this includes both secondary and primary prevention. The new inhibitors are for the patient that does not attain the desired target for LDL-C reduction while taking a maximum statin dose or who does not tolerate any statin dose whatsoever. Atherosclerosis can be considered a metabolic disease and the clinician needs to realize this and think more and more of CV prevention. These inhibitors can contribute to both the stabilization and regression of atherosclerotic plaques and thereby avoid or delay major adverse cardiac events. (United States)

Resumen: La historia de la proproteína convertasa subtilisin/kexin tipo 9 (PCSK9) es fascinante y la evolución del conocimiento de su función ha resultado en nuevos fármacos de gran importancia para el paciente cardiovascular. La PCSK9 funciona como un control negativo de receptores en la superficie de células para la lipoproteína de baja densidad con su componente de colesterol (LDL-C). El hallazgo inicial y clave fue que anormalidades diferentes de la PCSK9 resultan en un aumento o una disminución de la LDL-C, relacionados en una mayor o menor supresión de los receptores. Fueron estas observaciones las que proporcionaron evidencias indirectas a la idea de preparar anticuerpos monoclonales de la PCSK9 que pudieran disminuir su actividad y que esto se reflejara en receptores más activos para disminuir la LDL-C. El resto es una historia fascinante que ahora ofrece 2 inhibidores de la PCSK9, alirocumab y evolocumab, los cuales disminuyen la LDL-C en un 50%. Sin embargo, si no hay una contraindicación, las estatinas son el estándar de prevención para el paciente cardiovascular de alto riesgo e incluyen la prevención secundaria y primaria. Estos nuevos inhibidores están indicados en aquel paciente en el que no se obtiene el objetivo de tratamiento con la dosis máxima de una estatina o que no tolera ninguna de ellas. Debemos pensar en la aterosclerosis como una enfermedad metabólica y el clínico necesita darse cuenta de esta realidad y considerar las posibilidades disponibles para la prevención cardiovascular. Estos inhibidores pueden contribuir a la estabilización y regresión de placas ateroscleróticas y evitar episodios cardiovasculares mayores. (Estados Unidos)

Influence of PCSK9 gene E670G polymorphism on the risk of atherosclerotic coronary heart disease and plasma lipid level / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the influence of PCSK9 gene E670G polymorphism on the risk of coronary heart disease (CHD) among Chinese patients from Tianjin, and to compare the effect of atorvastatin treatment on CHD patients with various PCSK9 E670G genotypes.</p><p><b>METHODS</b>Seven hundred and seventy-eight patients undergoing coronary angiography (CAG) were classified into CHD group (n = 502) and control group (n = 276). Total cholesterol (TC) and triglyceride (TG) were determined for all patients. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to determine the E670G genotype for each patient. For 231 CHD patients who had taken atorvastatin calcium for 12 weeks and completed the follow-up, the lipid profile was determined again.</p><p><b>RESULTS</b>The distribution of PCSK9 E670G genotype between the CHD and control groups differed significantly (P< 0.01). The frequencies of G allele were 15.99% and 9.34% in the CHD and control group, respectively, which showed a statistical significance (P< 0.01). Carriers of G allele had a higher risk of CHD than those with A allele (OR=1.847, 95%CI: 1.301-2.622, P< 0.01). Among CHD patients, those carrying G allele had higher TC and TG levels than those with AA genotype, while patients with a GG genotype had higher level of low density lipoprotein cholesterol (LDL-C) than those with a AA genotype (P< 0.05). Logistic regression analysis indicated that high density lipoprotein cholesterol (HDL-C) is a protective factor of CHD (OR=0.203, 95%CI: 0.100-0.414, P< 0.05). After treatment with atorvastatin, LDL-C level decreased more significantly in those with an AA genotype compared with AG and GG genotypes (P< 0.05).</p><p><b>CONCLUSION</b>The E670G polymorphism of the PCSK9 gene is associated with the lipid levels and risk for CHD.</p>

Effects of Hedan Tablet () on lipid profile, proprotein convertase subtilisin/kexin type 9 and high-density lipoprotein subfractions in patients with hyperlipidemia: A primary study / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of Hedan Tablet () on serum lipid profile, proprotein convertase subtilisin/kexin type 9 (PSCK9) and high-density lipoprotein (HDL) subfractions in patients with hyperlipidemia.</p><p><b>METHODS</b>Thirty-seven patients with hyperlipidemia were randomized to treatment with Hedan Tablet 4.38 g/day as Hedan group (18 cases) or placebo (19 cases) as control group for 8 weeks. The lipid profile, PCSK9 and HDL subfractions were determined at day 0 and week 8 in both groups respectively.</p><p><b>RESULTS</b>Hedan treatment for 8 weeks mildly decreased serum low-density lipoprotein cholesterol (LDL-C) levels, while no changes were found in total cholesterol (TC), triglycerides (TG) and PCSK9 concentrations. Furthermore, Hedan treatment increased the concentration of large high-density lipoprotein cholesterol (HDL-C) and the percentage of large HDL subfraction, while decreased the concentration of small HDL-C and the percentage of small HDL subfraction without changing serum HDL-C levels in patients with hyperlipidemia.</p><p><b>CONCLUSION</b>Hedan treatment of 4.38 g per day for 8 weeks could confer a favorable effects on serum LDL-C concentration as well as HDL subfractions.</p>

Short- and long-term effects of xuezhikang, an extract of cholestin, on serum proprotein convertase subtilisin/kexin type 9 levels / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the short- and long-term effects of Xuezhikang (XZK), an extract of cholestin, on proprotein convertase subtilisin/kexin type 9 (PCSK9) level.</p><p><b>METHODS</b>Thirty rats were randomly divided into three groups and were given saline, XZK 1,200 mg/kg or lovastatin 10 mg/kg respectively by daily gavage for 3 days (n=10 for each). Sixteen patients without previous lipid-lowering drug treatment for dyslipidemia received XZK 1,200 mg daily for 8 weeks. Fasting blood samples and liver tissue were collected at day 3 for rats, while the blood samples were obtained at baseline and week 8 from patients. The serum PCSK9 and lipid profile were measured. The expression of hepatic low density lipoprotein (LDL) receptor and sterol regulatory element binding protein 2 (SREBP-2) were measured by real time-PCR.</p><p><b>RESULTS</b>PCSK9 levels in rats were significantly increased in the XZK and lovastatin groups (P=0.002, P=0.003 vs. control) at day 3, while no significant differences were found in the levels of lipid parameters. PCSK9 levels in patients increased by 34% (P=0.006 vs. baseline) accompanied by total cholesterol and LDL-cholesterol decreased by 22% and 28% P=0.001, P=0.002 vs. baseline). The hepatic mRNA levels of LDL-receptor and SREBP-2 were significantly increased in the XZK and lovastatin groups.</p><p><b>CONCLUSION</b>XZK has significant impact on PCSK9 in a short- and long-term manner in both rats and humans. Moreover, the data indicated that as lovastatin, XZK increased PCSK9 levels through SREBP-2 pathway.</p>

Inhibition of proprotein convertase subtilisin/kexin type 9: a novel mechanism of berberine and 8-hydroxy dihydroberberine against hyperlipidemia / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the effect and molecular mechanisms of different doses of 8-hydroxy dihydroberberine (Hdber) for the treatment of hyperlipidemia in rats.</p><p><b>METHODS</b>A rat model of hyperlipidemia was established by feeding rats a high-fat diet for 4 weeks in 70 rats of 80 animals, and 10 rats were randomly selected as control group. The hyperlipidemic rats were then randomly divided into the following groups: a model group (MOD); a berberine group [BBR, 156 mg/(kg day)]; Hdber groups, which were treated with different doses of Hdber [78, 39 and 19.5 mg/(kg day)]; and a simvastatin group [SIM, 4 mg/(kg day)]. The corresponding therapy was administered to the rats of each treatment via gastric tubes. Normal animals were used as a control group. The blood levels of various lipids, including total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, free fatty acid (FFA), apolipoprotein AI(Apo-AI) and apolipoprotein B (Apo-B) were examined. The protein expressions of low-density lipoprotein receptor (LDL-R), sterol regulatory element-binding protein 2 (SREBP-2), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) and proprotein convertase subtilisin/kexin type 9 (PCSK-9) in liver tissues were determined by Western blot analysis.</p><p><b>RESULTS</b>Compared with the control group of rats, the model group demonstrated a deteriorated blood lipid profile and exhibited increased expression levels of PCSK-9 protein in their liver tissues (P<0.01). In addition, the high-fat diet decreased the expression levels of LDL-R, SREBP-2 and HMGCR proteins in murine liver tissues. However, the addition of berberine or Hdber reversed the blood lipid profile changes (P<0.05 or P<0.01), decreased the expression levels of PCSK-9 proteins (P<0.01), and increased the expression levels of LDL-R proteins in the hyperlipidemic rats (P<0.01). These compounds did not significantly influence the expression levels of SREBP-2 and HMGCR proteins in the hyperlipidemic rats.</p><p><b>CONCLUSIONS</b>Hdber is effective in the treatment of hyperlipidemia in rats. The therapeutic mechanisms of Hdber may be associated with increasing the expression of LDL-R protein and decreasing the expression of PCSK-9 protein in liver tissues.</p>

A novel mutation in proprotein convertase subtilisin/kexin type 9 gene leads to familial hypercholesterolemia in a Chinese family / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Familial hypercholesterolemia (FH) is an autosomal disorder associated with elevated plasma low density lipoprotein (LDL) levels leading to premature coronary heart disease (CHD). As a result of long-term hyperlipemia, FH patients will present endarterium thickening and artherosclerosis. In the present study we scanned the related gene of a clinically diagnosed autosomal genetic hypercholesterolemia family for the possible mutations and established eukaryotic expression vector of mutation of proprotein convertase subtilisin/kexin type 9 (PCSK9) gene with gene recombination technique to investigate the contributions of the variation on low density lipoprotein receptor (LDL-R) metabolism and function alternation.</p><p><b>METHODS</b>Mutation detection was conducted for LDL-R, apolipoprotein B(100) (apoB(100)) and PCSK9 gene with nucleotide sequencing in a Chinese FH family. The full-length cDNA of wild type PCSK9 gene (WT-PCSK9) was obtained from Bel-7402. Site mutagenesis was used to establish the recombinant eukaryotic expression vector carrying pathogenic type of PCSK9 gene and the inserted fragment was sequenced. With the blank vector as control, liposome transfection method was used to transfect the Bel-7402 cells with recombinant plasmid. The expression of LDL-R mRNA was examined by RT-PCR. PCSK9 and the expression of LDL-R protein were determined by Western blotting.</p><p><b>RESULTS</b>The G-->T mutation at the 918 nucleotide of PCSK9 gene resulted in the substitution of the arginine by a serine at the codon 306 of exon 6. After sequencing, it was confirmed that the inserted fragment of established expression vector had correct size and sequence and the mutant was highly expressed in Bel-7402 cells. There was no significant variation in the levels of LDL-R mRNA. LDL-R mature protein was decreased by 57% after the cells were transfected by WT-PCSK9 plasmid. Mature LDL-R was significantly decreased by 12% after the cells were transfected by R306S mutant as evidenced by gray scale scanning, suggesting that the new mutant R306S can significantly decrease the expression of mature LDL-R protein.</p><p><b>CONCLUSIONS</b>A novel missense mutation of PCSK9 gene, R306S, was found and the eukaryotic expression vectors of mutant and wild-type of PCSK9 gene were established. There was no significant variation in the levels of LDL-R mRNA. The R306S mutation could significantly lead to the decrease of LDL-R mature protein expression, which might be the pathogenic gene of the FH family.</p>