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The clinical features and genetic variants of the patient with sitosterolemia who was referred to Shanghai Children′s Medical Center, Shanghai Jiaotong University School of Medicine from June 2019 to January 2020 were retrospectively analyzed.The patient was treated with Ezetimibe tablets combined with diet control, and the follow-up was performed regularly.Besides, a relevant literature review was conducted.A 7-year and 5-month-old boy was referred to the hospital for " repeated thrombocytopenia for 7 months" with normal serum cholesterol.The whole exome sequencing showed that compound heterozygous mutations (p.Arg446*, p.Gln251*) in ABCG5 gene were inherited from their parents respectively.Hence, he was diagnosed with sitosterolemia.After 29 days of treatment with Ezetimibe tablets combined with diet control, the patient′s platelets returned to normal values without obvious adverse reactions related to drugs.Children with sitosterolemia may present with rare thrombocytopenia, and the therapeutic effects of Ezetimibe tablets combined with diet control are favorable.
ABSTRACT
Phytosterolemia is a rare, severe autosomal recessive sterol storage disorder caused by homozygous or compound heterozygous mutations in one of the ABCG5 and/or ABCG8 adenosine triphosphate binding cassette (ABC) genes. The most prominent features of phytosterolemia are the significantly increased serum content of plant sterols. Present review focused on the laboratory diagnosis of phytosterolemia, briefly described the metabolism of phytosterols, and introduced the latest research progress on phytosterolemia diagnosis, its relationship with ASCVD and laboratory diagnostic methods (including the detection of serum concentrations of phytosterols, ABCG5/G8 gene mutation). We hope this article could improve readers′ awareness and attention on this disease.
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Objective To explore the relationship between SNPs in microRNA binding sites of ABCG5/8 and the glucolipid level during pregnancy.Methods 1 925 pregnant women were recruited at Peking Union Medical College hospital from 2006 to 2011.The clinical data were collected and the total genomic DNA was extracted from whole blood samples.ABCG5/8, which was reported to be related with the glucose and lipid metabolism closely, were selected as the candidate gene and the SNPs in its microRNA binding sites with minor allele frequency >5% in Han Chinese in Beijing were chosen.Then the genotyping was performed and analyzed.Results There was only one SNP matching the criteria, rs2278356, and it is significantly associated with LDL-C and TC level during pregnancy (LDL-C: b=0.104 mmol/L, 95% CI 0.023-0.185 mmol/L, P<0.05;TC: b=0.105 mmol/L, 95% CI 0.080-0.203 mmol/L, P<0.05).Conclusions The association of rs2278356 in 3′UTR of ABCG5/8 with LDL-C and TC level in pregnant Chinese Han women is found, which may provide an individualized treatment strategy for pregnant women with high cholesterol.
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Several proteins are involved in the absorption of cholesterol in small intestine.Niemann-Pick C1 like 1 (NPC1L1) mainly mediates the absorption of cholesterol, and acyl-coenzyme A ( CoA)∶cholesterol acyltransferase 2 (ACAT2) catalyzes the free cholesterol absorpted by intestine into cholesterol ester,while unesterified free cholesterol is secreted into intestinal lumen by ATP-binding cassette(ABC) transporters G5/G8(ABCG5/ABCG8).Transcription factor liver X receptor( LXR) plays an important role in the process of intestinal cholesterol absorption.The research progress in NPC1L1,ABCG5/ABCG8,ACAT2 and LXR is reviewed in this article.
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Objective: To explore the association between variant rs4299376 of ABCG5/ABCG8 gene with the risk of coronary heart disease (CHD) in Han Chinese and the association of related lipid levels with CHD. Methods: We collected blood samples from 290 CHD cases, 198 non-CHD controls and 331 healthy controls. The genomic DNA was acquired by the nucleic acid extraction automatic analyzer and the rs4299376 genotypes were analyzed by the Mass-ARRAY İPLEXR platform. Results: There were no significant differences in distribution of variant rs4299376 of ABCG5/ABCG8 gene among Han Chinese with CHD, non-CHD controls and healthy controls. There was no association between lipid levels and CHD in either total or male groups. While in female group, the triglyceride (TG) and total cholesterol (TC) were higher in CHD patients than in non-CHD controls (TG: 2. 23 ± 1. 05vs 1. 84 ± 1. 03, P = 0. 01; TC: 4. 7 9 ± 1. 17 vs 4. 36 ±1. 03, P = 0. 01). It was also found that, for those 60 years old and above, the CHD cases had a significantly lower high density lipoprotein (HDL) levll compared with non-CHD group (1. 09±0. 23 vs 1. 16±0. 25, P = 0. 03). Conclusion: There is no noticeable association between ABCG5/ ABCG8 rs4299376 polymorphism and the risk of CHD in Han Chinese. Female CHD patients have higher levels of TG and TC and when over 60 year old, CHD patients have a lower HDL level than non-CHD controls.
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Some compounds in the garlic inhibit cholesterol synthesis, resulting in lowering of serum cholesterol and triglycerides and increase in HDL level. However, the mechanism of this specific effect is not fully understood. In the small intestine, ATP-binding cassette transporters G5, G8 and A1 (ABCG5, ABCG8 and ABCA1), as well as Niemann-Pick C1 like 1 (NPC1L1) protein have important roles in cholesterol metabolism. In this study, we evaluated the beneficial effect of aqueous extract of garlic on lipid profile and also expression of npc1l1, abca1, abcg5 and abcg8 genes in the intestine of N-Marry mice fed a high cholesterol diet as a possible mechanism of garlic effect. Twenty-four mice were randomly divided into three groups: Group 1: hypercholesterolmic (received chow + 2% cholesterol + 0.5% cholic acid); Group 2: garlic (received chow + 4% (w/w) garlic extract + 2% cholesterol + 0.5% cholic acid); and Group 3: received chow only. After one month, mice were anesthetized and blood was collected from their heart. The jejunum was removed, washed with PBS and entrocytes were scraped and used for the experiments. Serum lipids were measured enzymatically and expression of mRNA levels for the above-mentioned proteins was determined by semi-quantitative RT-PCR. Garlic extract significantly reduced serum lipids (p<0.05), compared with the hypercholesterolemic group. Expression of the intestinal npc1l1 was significantly decreased (p<0.01) in the garlic group, compared with the chow group, while abcg5 (p<0.01), abcg8 (p<0.01) and abca1 (p<0.05) expressions were significantly increased. In conclusion, this study reveals a possible mechanism for the beneficial effects of the garlic in lowering serum lipids by decreasing the intestinal lipid absorption and increasing excretion of cholesterol back into the intestinal lumen.
Subject(s)
ATP Binding Cassette Transporter 1/genetics , ATP-Binding Cassette Transporters/genetics , Animals , Garlic/chemistry , Gene Expression Regulation/drug effects , Hypercholesterolemia/genetics , Intestines/drug effects , Intestines/metabolism , Lipids/blood , Lipoproteins/genetics , Membrane Transport Proteins/genetics , Mice , Plant Extracts/pharmacology , Water/chemistryABSTRACT
Las proteínas NPC1L1, ABCG5 y ABCG8 participan en la absorción intestinal de colesterol. Ezetimiba inhibe este proceso bloqueando a NPC1L1, sin embargo, su efecto sobre ABCG5 y ABCG8 aún no está claro. Así, el objetivo del presente trabajo fue evaluar en ratones C57BL/6 con hipercolesterolemia inducida por dieta y tratados con ezetimiba, la expresión de NPC1L1, ABCG5 y ABCG8 mediante PCR en tiempo real y Western blot, en 3 grupos de animales: 1, dieta hipercolesterolémica D12336; 2, dieta D12336 más 5 mg/kg/día de ezetimiba; 3, dieta control. El nivel sérico de colesterol total fue significativamente diferente entre los grupos estudiados (control: 1,85 +/- 0,49 mmol/L; dieta D12336: 3,11 +/- 0,73 mmol/L; ezetimiba: 2,11 +/- 0,50 mmol/L, P = 0,001). La expresión génica de NPC1L1 aumentó 5,4 veces en el grupo que recibió la dieta D12336 (P = 0,003). Por otro lado, la expresión génica de ABCG5 y ABCG8 no fue diferente en el grupo con hipercolesterolemia (P = 0,239 y P = 0,201, respectivamente). Después del tratamiento con ezetimiba, la expresión génica de ABCG5 se incrementó 15,6 veces (P = 0.038). No hubo diferencias significativas en la expresión génica de NPC1L1 (P = 0,134) y ABCG8 (P = 0,067). En relación a la expresión proteica, la dieta D12336 incrementó los niveles de expresión de NPC1L1 (P = 0,022) y ABCG5 (P = 0,008); el tratamiento con ezetimiba incrementó los niveles de NPC1L1 (P = 0,048) y redujo los niveles de ABCG5 (P = 0,036) y ABCG8 (P = 0,016). En conclusión, nuestros resultados sugieren que tanto la dieta hipercolesterolémica como el tratamiento con ezetimiba, en un modelo experimental, afectan los niveles de expresión de NPC1L1, ABCG5 y ABCG8, sugiriendo que ABCG5 y ABCG8 están involucrados en la respuesta hipolipemiante a este fármaco. No obstante, el mecanismo mediante el cual se explica esta interacción requiere de un futuro estudio.
Proteins NPC1L1, ABCG5 and ABCG8 are involved in the intestinal absorption of cholesterol. Ezetimibe inhibits this process by blocking NPC1L1, however, its effect on ABCG5 and ABCG8 is not yet clear. Thus, the objective of this study was to evaluate in C57BL / 6 mice with diet-induced hypercholesterolemia treated with ezetimibe, the expression of NPC1L1, ABCG5 and ABCG8 by real time PCR and Western blot, in 3 groups of animals: 1, diet hypercholesterolemic D12336, 2, D12336 diet plus 5 mg/kg/ day of ezetimibe, 3, diet control. The serum level of total cholesterol was significantly different between groups (control: 1.85 +/- 0.49 mmol / L; diet D12336: 3.11 +/- 0.73 mmol / L; ezetimibe: 2.11 +/- 0.50 mmol / L, P = 0.001). NPC1L1 gene expression increased 5.4-fold in the group receiving the diet D12336 (P = 0.003). Furthermore, the gene expression of ABCG5 and ABCG8 was not different in the group with hypercholesterolemia (P = 0.239 and P = 0.201, respectively). After treatment with ezetimibe, ABCG5 gene expression was increased 15.6 times (P = 0.038). No significant differences in gene expression of NPC1L1 (P = 0.134) and ABCG8 (P = 0.067). Regarding protein expression, the D12336 diet increased the levels of expression of NPC1L1 (P = 0.022) and ABCG5 (P = 0.008), treatment with ezetimibe increased the levels of NPC1L1 (P = 0.048) and reduced levels of ABCG5 (P = 0.036) and ABCG8 (P = 0.016). In conclusion, our results suggest that both hypercholesterolemic diet as treatment with ezetimibe, in an experimental model, affect the expression levels of NPC1L1, ABCG5 and ABCG8, suggesting that ABCG5 and ABCG8 are involved in lipid-lowering response to this drug. However, the mechanism by which this interaction is explained requires further study.
Subject(s)
Animals , Rats , Anticholesteremic Agents/administration & dosage , Azetidines/administration & dosage , Hypercholesterolemia/drug therapy , Lipoproteins/physiology , Membrane Transport Proteins/physiology , ATP-Binding Cassette Transporters/physiology , Blotting, Western , Cholesterol, Dietary , Disease Models, Animal , Gene Expression , Lipoproteins/genetics , Membrane Transport Proteins/genetics , Real-Time Polymerase Chain Reaction , ATP-Binding Cassette Transporters/geneticsABSTRACT
In this study we evaluated the possible association between five single nucleotide polymorphisms in ABCG5 (rs6720173) and ABCG8 (rs11887534, rs4148211, rs4148217 and rs6544718) genes and ezetimibe response in Chilean hypercholesterolemic subjects. A total of 60 non-related hypercholesterolemic subjects, aged 18 to 65 years old were included in this study. These subjects were treated with ezetimibe (10mg/day) during one month. The ABCG5 and ABCG8 genotypes were assessed by PCR-RFLP. The genotype distribution of the ABCG5/ABCG8 polymorphisms was in Hardy-Weinberg equilibrium. Our results showed that the investigated polymorphisms were not associated with the response to ezetimibe. Nevertheless, the T allele of rs6544718 polymorphism was related to higher baseline levels of LDL-cholesterol (p<0.001). In addition, the G allele for the rs4148211 polymorphism was associated with greater baseline concentrations of triglycerides (P=0.019). This allele was also associated with lower concentrations of HDL-cholesterol (P=0.027), after ezetimibe treatment. Our results suggest that the studied polymorphisms do not affect the therapeutic response to ezetimibe in the evaluated subjects.
En este estudio se evaluó la posible asociación entre cinco polimorfismos de nucleótido único en los genes ABCG5 (rs6720173) y ABCG8 (rs11887534, rs4148211, rs4148217 y rs6544718) y la respuesta a ezetimiba en pacientes hipercolesterolémicos chilenos. Un total de 60 individuos hipercolesterolemicos, no relacionados, con edades entre 18 y 65 años fueron incluidos. Estos sujetos fueron tratados con ezetimiba (10mg/día) durante un mes. Los genotipos de ABCG5 y ABCG8 fueron evaluados por PCR-RFLP. La distribución de genotipos de los polimorfismos de ABCG5/ABCG8 se encontraba en equilibrio de Hardy-Weinberg. Nuestros resultados mostraron que los polimorfismos estudiados no se asociaron con la respuesta a la ezetimiba. Sin embargo, el alelo T del polimorfismo rs6544718 fue relacionado con niveles basales elevados de LDL-colesterol (p <0,001). Además, el alelo G para el polimorfismo rs4148211 se asoció con una mayor concentración basal de triglicéridos (p = 0,019). Este alelo también se asoció con concentraciones más bajas de HDL-colesterol (p = 0,027), después del tratamiento con ezetimiba. Nuestros resultados sugieren que los polimorfismos estudiados no afectan a la respuesta terapéutica a la ezetimiba en los sujetos evaluados.
Subject(s)
Female , Middle Aged , Azetidines/pharmacology , Hypercholesterolemia/genetics , Polymorphism, Genetic , ATP-Binding Cassette Transporters/genetics , Anticholesteremic Agents/pharmacology , Genetic Variation , Cholesterol, HDL , Cholesterol, HDL/blood , Hypercholesterolemia/drug therapy , Cholesterol, LDL , Cholesterol, LDL/blood , Polymorphism, Restriction Fragment Length , Polymerase Chain Reaction/methods , Triglycerides/bloodABSTRACT
BACKGROUND AND OBJECTIVES: Excretion of bile acid and free cholesterol of bile was important to maintain cholesterol homeostasis. ATP-binding cassette transporter G5 (ABCG5) and G8 (ABCG8) promoted biliary cholesterol excretion. In previous study, hepatic secretion of cholesterol and ABCG5/G8 expression are strongly stimulated in hypophysectomized rats during treatment with thyroid hormone. In this study, we aimed to evaluate the effect of thyroid hormone to expression of ABCG5 and G8 in mouse liver. MATERIALS AND METHODS: We administered thyroid hormone (T3) to C57BL/6 mice and then RNA and protein was isolated from liver. We isolated primary hepatocyte and administered T3 to evaluate in vitro effect. HepG2 cells were cotransfected with either a control plasmid or expression plasmids for human thyroid hormone receptor (hTR)beta/human retinoid X receptor (hRXR)alpha or human liver X receptor (hLXR)alpha in combination with reporter plasmids TK-LXRE3-LUC with or without T3. RESULTS: Serum total cholesterol was decreased after 5 days of T3 treatment. Expression of ABCG5/8 mRNA and ABCG5 protein was increased after T3 treatment. In primary hepatocytes, T3 also increased ABCG5/8 mRNA expression. LXRalpha mRNA was not increased by T3. However, when we cotransfected liver X receptor response element (LXRE) construct and TRbeta/RXRalpha with T3, the activity of LXRE containing construct was markedly increased. CONCLUSION: We confirmed that thyroid hormone increased expression of ABCG5/8. This result suggested that thyroid hormone played an important role in decreasing serum cholesterol through bile excretion.