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Aim: Methylation of LDLR, PCSK9 and LDLRAP1 CpG sites was assessed in patients with familial hypercholesterolemia (FH). Methods: DNA methylation of was analyzed by pyrosequencing in 131 FH patients and 23 normolipidemic (NL) subjects.Results:  LDLR, PCSK9 and LDLRP1 methylation was similar between FH patients positive (MD) and negative (non-MD) for pathogenic variants in FH-related genes. LDLR and PCSK9 methylation was higher in MD and non-MD groups than NL subjects (p < 0.05). LDLR, PCSK9 and LDLRAP1 methylation profiles were associated with clinical manifestations and cardiovascular events in FH patients (p < 0.05).Conclusion: Differential methylation of LDLR, PCSK9 and LDLRAP1 is associated with hypercholesterolemia and cardiovascular events. This methylation profile maybe useful as a biomarker and contribute to the management of FH.

[Box: see text].

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INTRODUCTION: In Mexico, familial hypercholesterolemia (FH) is underdiagnosed, but population screening in small communities where at least one homozygous patient has already been detected results in a useful and inexpensive approach to reduce this problem. Considering that we previously reported nine homozygous cases from the state of Oaxaca, we decided to perform a population screening to identify patients with FH and to describe both their biochemical and genetic characteristics. METHODS: LDL cholesterol (LDLc) was quantified in 2,093 individuals from 11 communities in Oaxaca; either adults with LDLc levels ≥170 mg/dL or children with LDLc ≥130 mg/dL were classified as suggestive of FH and therefore included in the genetic study. LDLR and APOB (547bp fragment of exon 26) genes were screened by sequencing and MLPA analysis. RESULTS: Two hundred and five individuals had suggestive FH, with a mean LDLc of 223 ± 54 mg/dL (range: 131-383 mg/dL). Two pathogenic variants in the LDLR gene were detected in 149 individuals: c.-139_-130del (n = 1) and c.2271del (n = 148). All patients had a heterozygous genotype. With the cascade screening of their relatives (n = 177), 15 heterozygous individuals for the c.2271del variant were identified, presenting a mean LDLc of 133 ± 35 mg/dL (range: 60-168 mg/dL). CONCLUSIONS: The FH frequency in this study was 7.8% (164/2093), the highest reported worldwide. A founder effect combined with inbreeding could be responsible for the high percentage of patients with the LDLR c.2271del variant (99.4%), which allowed us to detect both significant biochemical heterogeneity and incomplete penetrance; hence, we assumed the presence of phenotype-modifying variants.

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Aim: Methylation of LDLR, PCSK9 and LDLRAP1 CpG sites was assessed in patients with familialhypercholesterolemia (FH). Methods: DNA methylation of was analyzed by pyrosequencing in 131FH patients and 23 normolipidemic (NL) subjects. Results: LDLR, PCSK9 and LDLRP1 methylationwas similar between FH patients positive (MD) and negative (non-MD) for pathogenic variantsin FH-related genes. LDLR and PCSK9 methylation was higher in MD and non-MD groups thanNL subjects (p < 0.05). LDLR, PCSK9 and LDLRAP1 methylation profiles were associated withclinical manifestations and cardiovascular events in FH patients (p < 0.05). Conclusion: Differentialmethylation of LDLR, PCSK9 and LDLRAP1 is associated with hypercholesterolemia and cardiovascularevents. This methylation profile maybe useful as a biomarker and contribute to the management ofFH.

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BACKGROUND: Familial hypercholesterolemia (FH) is caused by pathogenic variants in low-density lipoprotein (LDL) receptor (LDLR) or its associated genes, including apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and LDLR adaptor protein 1 (LDLRAP1). However, approximately 40% of the FH patients clinically diagnosed (based on FH phenotypes) may not carry a causal variant in a FH-related gene. Variants located at 3' untranslated region (UTR) of FH-related genes could elucidate mechanisms involved in FH pathogenesis. This study used a computational approach to assess the effects of 3'UTR variants in FH-related genes on miRNAs molecular interactions and to explore the association of these variants with molecular diagnosis of FH. METHODS AND RESULTS: Exons and regulatory regions of FH-related genes were sequenced in 83 FH patients using an exon-target gene sequencing strategy. In silico prediction tools were used to study the effects of 3´UTR variants on interactions between miRNAs and target mRNAs. Pathogenic variants in FH-related genes (molecular diagnosis) were detected in 44.6% FH patients. Among 59 3'UTR variants identified, LDLR rs5742911 and PCSK9 rs17111557 were associated with molecular diagnosis of FH, whereas LDLR rs7258146 and rs7254521 and LDLRAP1 rs397860393 had an opposite effect (p < 0.05). 3´UTR variants in LDLR (rs5742911, rs7258146, rs7254521) and PCSK9 (rs17111557) disrupt interactions with several miRNAs, and more stable bindings were found with LDLR (miR-4435, miR-509-3 and miR-502) and PCSK9 (miR-4796). CONCLUSION: LDLR and PCSK9 3´UTR variants disturb miRNA:mRNA interactions that could affect gene expression and are potentially associated with molecular diagnosis of FH.

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Familial hypercholesterolemia (FH) is caused by mutations in the gene that encodes the low-density lipoprotein (LDL) receptor, which leads to an excessive increase in plasma LDL cholesterol levels. Previous studies have shown that FH is associated with gliosis, blood-brain barrier dysfunction, and memory impairment, but the mechanisms associated with these events are still not fully understood. Therefore, we aimed to investigate the role of microgliosis in the neurochemical and behavioral changes associated with FH using LDL receptor knockout (LDLr-/- ) mice. We noticed that microgliosis was more severe in the hippocampus of middle-aged LDLr-/- mice, which was accompanied by microglial morphological changes and alterations in the immunocontent of synaptic protein markers. At three months of age, the LDLr-/- mice already showed increased microgliosis and decreased immunocontent of claudin-5 in the prefrontal cortex (PFC). Subsequently, 6-month-old male C57BL/6 wild-type and LDLr-/- mice were treated once daily for 30 days with minocycline (a pharmacological inhibitor of microglial cell reactivity) or vehicle (saline). Adult LDLr-/- mice displayed significant hippocampal memory impairment, which was ameliorated by minocycline treatment. Non-treated LDLr-/- mice showed increased microglial density in all hippocampal regions analyzed, a process that was not altered by minocycline treatment. Region-specific microglial morphological analysis revealed different effects of genotype or minocycline treatment on microglial morphology, depending on the hippocampal subregion analyzed. Moreover, 6-month-old LDLr-/- mice exhibited a slight but not significant increase in IBA-1 immunoreactivity in the PFC, which was reduced by minocycline treatment without altering microglial morphology. Minocycline treatment also reduced the presence of microglia within the perivascular area in both the PFC and hippocampus of LDLr-/- mice. However, no significant effects of either genotype or minocycline treatment were observed regarding the phagocytic activity of microglia in the PFC and hippocampus. Our results demonstrate that hippocampal microgliosis, microglial morphological changes, and the presence of these glial cells in the perivascular area, but not increased microglial phagocytic activity, are associated with cognitive deficits in a mouse model of FH.

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Familial hypercholesterolemia (FH) is caused by deleterious mutations in the LDLR that increase markedly low-density lipoprotein (LDL) cholesterol and cause premature atherosclerotic cardiovascular disease. Functional effects of pathogenic LDLR variants identified in Brazilian FH patients were assessed using in vitro and in silico studies. Variants in LDLR and other FH-related genes were detected by exon-target gene sequencing. T-lymphocytes were isolated from 26 FH patients, and 3 healthy controls and LDLR expression and activity were assessed by flow cytometry and confocal microscopy. The impact of LDLR missense variants on protein structure was assessed by molecular modeling analysis. Ten pathogenic or likely pathogenic LDLR variants (six missense, two stop-gain, one frameshift, and one in splicing region) and six non-pathogenic variants were identified. Carriers of pathogenic and non-pathogenic variants had lower LDL binding and uptake in activated T-lymphocytes compared to controls (p < 0.05), but these variants did not influence LDLR expression on cell surface. Reduced LDL binding and uptake was also observed in carriers of LDLR null and defective variants. Modeling analysis showed that p.(Ala431Thr), p.(Gly549Asp) and p.(Gly592Glu) disturb intramolecular interactions of LDLR, and p.(Gly373Asp) and p.(Ile488Thr) reduce the stability of the LDLR protein. Docking and molecular interactions analyses showed that p.(Cys184Tyr) and p.(Gly373Asp) alter interaction of LDLR with Apolipoprotein B (ApoB). In conclusion, LDLR null and defective variants reduce LDL binding capacity and uptake in activated T-lymphocytes of FH patients and LDLR missense variants affect LDLR conformational stability and dissociation of the LDLR-ApoB complex, having a potential role in FH pathogenesis.

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Abstract Consuming a high-fat diet causes a harmful accumulation of fat in the liver, which may not reverse even after switching to a healthier diet. Different reports dealt with the role of purslane as an extract against high-fat diet; meanwhile, it was necessary to study the potential role of fresh purslane as a hypolipidemic agent. This study is supposed to investigate further the potential mechanism in the hypolipidemic effect of fresh purslane, by measuring cholesterol 7a-hydroxylase (CYP7A1) and low-density lipoprotein receptor (Ldlr). Rats were divided into two main groups: the first one is the normal control group (n=7 rats) and the second group (n=28 rats) received a high fat diet for 28 weeks to induce obesity. Then the high fat diet group was divided into equal four subgroups. As, the positive control group still fed on a high fat diet only. Meanwhile, the other three groups were received high-fat diet supplemented with a different percent of fresh purslane (25, 50 and 75%) respectively. At the end of the experiment, rats were sacrificed and samples were collected for molecular, biochemical, and histological studies. Current study reported that, supplementation of fresh purslane especially at a concentration of 75% play an important role against harmful effects of high-fat diet at both cellular and organ level, by increasing CYP7A1 as well as Ldlr mRNA expression. Also, there were an improvement on the tested liver functions, thyroid hormones, and lipid profile. Fresh purslane plays the potential role as a hypolipidemic agent via modulation of both Ldlr and Cyp7A, which will point to use fresh purslane against harmful effects of obesity.

Resumo O consumo de uma dieta rica em gordura causa um acúmulo prejudicial de gordura no fígado, que pode não reverter mesmo após a mudança para uma dieta mais saudável. Diferentes relatórios trataram do papel da beldroega como um extrato contra uma dieta rica em gordura; entretanto, foi necessário estudar o papel potencial da beldroega fresca como agente hipolipemiante. Este estudo pretende investigar mais profundamente o mecanismo potencial no efeito hipolipidêmico da beldroega fresca, medindo o colesterol 7a-hidroxilase (CYP7A1) e o receptor de lipoproteína de baixa densidade (Ldlr). Os ratos foram divididos em dois grupos principais: o primeiro é o grupo controle normal (n = 7 ratos) e o segundo grupo (n = 28 ratos) recebeu dieta rica em gorduras por 28 semanas para induzir a obesidade. Em seguida, o grupo de dieta rica em gordura foi dividido em quatro subgrupos iguais. Como, o grupo de controle positivo ainda se alimentava apenas com dieta rica em gordura. Enquanto isso, os outros três grupos receberam dieta rica em gordura suplementada com diferentes porcentagens de beldroegas frescas (25%, 50% e 75%), respectivamente. Ao final do experimento, os ratos foram sacrificados e amostras coletadas para estudos moleculares, bioquímica e histológicos. O estudo atual relatou que a suplementação de beldroegas frescas, especialmente a uma concentração de 75%, desempenha papel importante contra os efeitos prejudiciais da dieta rica em gordura em nível celular e orgânico, aumentando a expressão de CYP7A1 e Ldlr mRNA. Além disso, houve melhora nas funções hepáticas testadas, nos hormônios tireoidianos e no perfil lipídico. Beldroegas frescas desempenham papel potencial como agente hipolipemiante por meio da modulação de Ldlr e Cyp7A, o que apontará para o uso de beldroegas frescas contra os efeitos nocivos da obesidade.

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Consuming a high-fat diet causes a harmful accumulation of fat in the liver, which may not reverse even after switching to a healthier diet. Different reports dealt with the role of purslane as an extract against high-fat diet; meanwhile, it was necessary to study the potential role of fresh purslane as a hypolipidemic agent. This study is supposed to investigate further the potential mechanism in the hypolipidemic effect of fresh purslane, by measuring cholesterol 7a-hydroxylase (CYP7A1) and low-density lipoprotein receptor (Ldlr). Rats were divided into two main groups: the first one is the normal control group (n=7 rats) and the second group (n=28 rats) received a high fat diet for 28 weeks to induce obesity. Then the high fat diet group was divided into equal four subgroups. As, the positive control group still fed on a high fat diet only. Meanwhile, the other three groups were received high-fat diet supplemented with a different percent of fresh purslane (25, 50 and 75%) respectively. At the end of the experiment, rats were sacrificed and samples were collected for molecular, biochemical, and histological studies. Current study reported that, supplementation of fresh purslane especially at a concentration of 75% play an important role against harmful effects of high-fat diet at both cellular and organ level, by increasing CYP7A1 as well as Ldlr mRNA expression. Also, there were an improvement on the tested liver functions, thyroid hormones, and lipid profile. Fresh purslane plays the potential role as a hypolipidemic agent via modulation of both Ldlr and Cyp7A, which will point to use fresh purslane against harmful effects of obesity.

O consumo de uma dieta rica em gordura causa um acúmulo prejudicial de gordura no fígado, que pode não reverter mesmo após a mudança para uma dieta mais saudável. Diferentes relatórios trataram do papel da beldroega como um extrato contra uma dieta rica em gordura; entretanto, foi necessário estudar o papel potencial da beldroega fresca como agente hipolipemiante. Este estudo pretende investigar mais profundamente o mecanismo potencial no efeito hipolipidêmico da beldroega fresca, medindo o colesterol 7a-hidroxilase (CYP7A1) e o receptor de lipoproteína de baixa densidade (Ldlr). Os ratos foram divididos em dois grupos principais: o primeiro é o grupo controle normal (n = 7 ratos) e o segundo grupo (n = 28 ratos) recebeu dieta rica em gorduras por 28 semanas para induzir a obesidade. Em seguida, o grupo de dieta rica em gordura foi dividido em quatro subgrupos iguais. Como, o grupo de controle positivo ainda se alimentava apenas com dieta rica em gordura. Enquanto isso, os outros três grupos receberam dieta rica em gordura suplementada com diferentes porcentagens de beldroegas frescas (25%, 50% e 75%), respectivamente. Ao final do experimento, os ratos foram sacrificados e amostras coletadas para estudos moleculares, bioquímica e histológicos. O estudo atual relatou que a suplementação de beldroegas frescas, especialmente a uma concentração de 75%, desempenha papel importante contra os efeitos prejudiciais da dieta rica em gordura em nível celular e orgânico, aumentando a expressão de CYP7A1 e Ldlr mRNA. Além disso, houve melhora nas funções hepáticas testadas, nos hormônios tireoidianos e no perfil lipídico. Beldroegas frescas desempenham papel potencial como agente hipolipemiante por meio da modulação de Ldlr e Cyp7A, o que apontará para o uso de beldroegas frescas contra os efeitos nocivos da obesidade.

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Abstract Consuming a high-fat diet causes a harmful accumulation of fat in the liver, which may not reverse even after switching to a healthier diet. Different reports dealt with the role of purslane as an extract against high-fat diet; meanwhile, it was necessary to study the potential role of fresh purslane as a hypolipidemic agent. This study is supposed to investigate further the potential mechanism in the hypolipidemic effect of fresh purslane, by measuring cholesterol 7a-hydroxylase (CYP7A1) and low-density lipoprotein receptor (Ldlr). Rats were divided into two main groups: the first one is the normal control group (n=7 rats) and the second group (n=28 rats) received a high fat diet for 28 weeks to induce obesity. Then the high fat diet group was divided into equal four subgroups. As, the positive control group still fed on a high fat diet only. Meanwhile, the other three groups were received high-fat diet supplemented with a different percent of fresh purslane (25, 50 and 75%) respectively. At the end of the experiment, rats were sacrificed and samples were collected for molecular, biochemical, and histological studies. Current study reported that, supplementation of fresh purslane especially at a concentration of 75% play an important role against harmful effects of high-fat diet at both cellular and organ level, by increasing CYP7A1 as well as Ldlr mRNA expression. Also, there were an improvement on the tested liver functions, thyroid hormones, and lipid profile. Fresh purslane plays the potential role as a hypolipidemic agent via modulation of both Ldlr and Cyp7A, which will point to use fresh purslane against harmful effects of obesity.

Resumo O consumo de uma dieta rica em gordura causa um acúmulo prejudicial de gordura no fígado, que pode não reverter mesmo após a mudança para uma dieta mais saudável. Diferentes relatórios trataram do papel da beldroega como um extrato contra uma dieta rica em gordura; entretanto, foi necessário estudar o papel potencial da beldroega fresca como agente hipolipemiante. Este estudo pretende investigar mais profundamente o mecanismo potencial no efeito hipolipidêmico da beldroega fresca, medindo o colesterol 7a-hidroxilase (CYP7A1) e o receptor de lipoproteína de baixa densidade (Ldlr). Os ratos foram divididos em dois grupos principais: o primeiro é o grupo controle normal (n = 7 ratos) e o segundo grupo (n = 28 ratos) recebeu dieta rica em gorduras por 28 semanas para induzir a obesidade. Em seguida, o grupo de dieta rica em gordura foi dividido em quatro subgrupos iguais. Como, o grupo de controle positivo ainda se alimentava apenas com dieta rica em gordura. Enquanto isso, os outros três grupos receberam dieta rica em gordura suplementada com diferentes porcentagens de beldroegas frescas (25%, 50% e 75%), respectivamente. Ao final do experimento, os ratos foram sacrificados e amostras coletadas para estudos moleculares, bioquímica e histológicos. O estudo atual relatou que a suplementação de beldroegas frescas, especialmente a uma concentração de 75%, desempenha papel importante contra os efeitos prejudiciais da dieta rica em gordura em nível celular e orgânico, aumentando a expressão de CYP7A1 e Ldlr mRNA. Além disso, houve melhora nas funções hepáticas testadas, nos hormônios tireoidianos e no perfil lipídico. Beldroegas frescas desempenham papel potencial como agente hipolipemiante por meio da modulação de Ldlr e Cyp7A, o que apontará para o uso de beldroegas frescas contra os efeitos nocivos da obesidade.

RESUMO

Consuming a high-fat diet causes a harmful accumulation of fat in the liver, which may not reverse even after switching to a healthier diet. Different reports dealt with the role of purslane as an extract against high-fat diet; meanwhile, it was necessary to study the potential role of fresh purslane as a hypolipidemic agent. This study is supposed to investigate further the potential mechanism in the hypolipidemic effect of fresh purslane, by measuring cholesterol 7a-hydroxylase (CYP7A1) and low-density lipoprotein receptor (Ldlr). Rats were divided into two main groups: the first one is the normal control group (n=7 rats) and the second group (n=28 rats) received a high fat diet for 28 weeks to induce obesity. Then the high fat diet group was divided into equal four subgroups. As, the positive control group still fed on a high fat diet only. Meanwhile, the other three groups were received high-fat diet supplemented with a different percent of fresh purslane (25, 50 and 75%) respectively. At the end of the experiment, rats were sacrificed and samples were collected for molecular, biochemical, and histological studies. Current study reported that, supplementation of fresh purslane especially at a concentration of 75% play an important role against harmful effects of high-fat diet at both cellular and organ level, by increasing CYP7A1 as well as Ldlr mRNA expression. Also, there were an improvement on the tested liver functions, thyroid hormones, and lipid profile. Fresh purslane plays the potential role as a hypolipidemic agent via modulation of both Ldlr and Cyp7A, which will point to use fresh purslane against harmful effects of obesity.(AU)

O consumo de uma dieta rica em gordura causa um acúmulo prejudicial de gordura no fígado, que pode não reverter mesmo após a mudança para uma dieta mais saudável. Diferentes relatórios trataram do papel da beldroega como um extrato contra uma dieta rica em gordura; entretanto, foi necessário estudar o papel potencial da beldroega fresca como agente hipolipemiante. Este estudo pretende investigar mais profundamente o mecanismo potencial no efeito hipolipidêmico da beldroega fresca, medindo o colesterol 7a-hidroxilase (CYP7A1) e o receptor de lipoproteína de baixa densidade (Ldlr). Os ratos foram divididos em dois grupos principais: o primeiro é o grupo controle normal (n = 7 ratos) e o segundo grupo (n = 28 ratos) recebeu dieta rica em gorduras por 28 semanas para induzir a obesidade. Em seguida, o grupo de dieta rica em gordura foi dividido em quatro subgrupos iguais. Como, o grupo de controle positivo ainda se alimentava apenas com dieta rica em gordura. Enquanto isso, os outros três grupos receberam dieta rica em gordura suplementada com diferentes porcentagens de beldroegas frescas (25%, 50% e 75%), respectivamente. Ao final do experimento, os ratos foram sacrificados e amostras coletadas para estudos moleculares, bioquímica e histológicos. O estudo atual relatou que a suplementação de beldroegas frescas, especialmente a uma concentração de 75%, desempenha papel importante contra os efeitos prejudiciais da dieta rica em gordura em nível celular e orgânico, aumentando a expressão de CYP7A1 e Ldlr mRNA. Além disso, houve melhora nas funções hepáticas testadas, nos hormônios tireoidianos e no perfil lipídico. Beldroegas frescas desempenham papel potencial como agente hipolipemiante por meio da modulação de Ldlr e Cyp7A, o que apontará para o uso de beldroegas frescas contra os efeitos nocivos da obesidade.(AU)

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Maternal metabolic status influences pregnancy and, consequently, the perinatal outcome. Resistin is a pro-inflammatory adipokine predominantly expressed and secreted by mononuclear cells, adipose tissue, and placental trophoblastic cells during pregnancy. Recently, we reported an inverse association between maternal resistin levels and fetal low-density lipoprotein cholesterol (LDL-C). Then, in this work, we used a human placental explant model and the trophoblast cell line JEG-3 to evaluate whether resistin affects placental LDL-C uptake. Resistin exposure induced the transcription factor SREBP-2, LDLR, and PCSK9 mRNA expression, and changes at the protein level were confirmed by immunohistochemistry and Western blot. However, for LDLR, the changes were not consistent between mRNA and protein levels. Using a labeled LDL-cholesterol (BODIPY FL LDL), uptake assay demonstrated that the LDL-C was significantly decreased in placental explants exposed to a high dose of resistin and a lesser extent in JEG-3 cells. In summary, resistin induces PCSK9 expression in placental explants and JEG-3 cells, which could be related to negative regulation of the LDLR by lysosomal degradation. These findings suggest that resistin may significantly regulate the LDL-C uptake and transport from the maternal circulation to the fetus, affecting its growth and lipid profile.

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Knowledge of epidemiology, genetic etiopathogenesis, diagnostic criteria, and management of familial hypercholesterolemia have increased in the last two decades. Several population studies have shown that familial hypercholesterolemia is more frequent than previously thought, making this entity the most common metabolic disease with monogenic inheritance in the world. Identification of causal heterozygous pathogenic variants in LDLR, APOB, and PCSK9 genes has increased diagnostic accuracy of classical criteria (extreme hypercholesterolemia, personal / family history of premature coronary artery disease or other cardiovascular diseases). Genetic screening has been recently introduced in many European countries to detect patients with familial hypercholesterolemia, mainly affected pediatric subjects, asymptomatic or those at the beggining of their disease, to increase surveillance and avoid complications such as cardiovascular diseases. Cholesterol- lowering drugs should be started as soon as the diagnosis is made. Various combinations between drugs can be used when the goal is not achieved. New therapies, including small interference ribonucleic acids (siRNA) are being tested in different clinical trials.

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Although the benefits of moderate intake of red wine in decreasing incidence of cardiovascular diseases associated to hypercholesterolemia are well recognized, there are still widespread misconceptions about its effects on the hypercholesterolemia-related cognitive impairments. Herein we investigated the putative benefits of regular red wine consumption on cognitive performance of low-density lipoprotein receptor knockout (LDLr-/-) mice, an animal model of familial hypercholesterolemia, which display cognitive impairments since early ages. The red wine was diluted into the drinking water to a final concentration of 6% ethanol and was available for 60 days for LDLr-/- mice fed a normal or high-cholesterol diet. The results indicated that moderate red wine consumption did not alter locomotor parameters and liver toxicity. Across multiple cognitive tasks evaluating spatial learning/reference memory and recognition/identification memory, hypercholesterolemic mice drinking red wine performed significantly better than water group, regardless of diet. Additionally, immunofluorescence assays indicated a reduction of astrocyte activation and lectin stain in the hippocampus of LDLr-/- mice under consumption of red wine. These findings demonstrate that the moderate consumption of red wine attenuates short- and long-term memory decline associated with hypercholesterolemia in mice and suggest that it could be through a neurovascular action.

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BACKGROUND: Evidence has revealed an association between familial hypercholesterolemia and cognitive impairment. In this regard, a connection between cognitive deficits and hippocampal blood-brain barrier (BBB) breakdown was found in low-density lipoprotein receptor knockout mice (LDLr-/-), a mouse model of familial hypercholesterolemia. OBJECTIVE: Herein we investigated the impact of a hypercholesterolemic diet on cognition and BBB function in C57BL/6 wild-type and LDLr-/-mice. METHODS: Animals were fed with normal or high cholesterol diets for 30 days. Thus, wild-type and LDLr-/-mice were submitted to memory paradigms. Additionally, BBB integrity was evaluated in the mice's prefrontal cortices and hippocampi. RESULTS: A tenfold elevation in plasma cholesterol levels of LDLr-/-mice was observed after a hypercholesterolemic diet, while in wild-type mice, the hypercholesterolemic diet exposure increased plasma cholesterol levels only moderately and did not induce cognitive impairment. LDLr-/-mice presented memory impairment regardless of the diet. We observed BBB disruption as an increased permeability to sodium fluorescein in the prefrontal cortices and hippocampi and a decrease on hippocampal claudin-5 and occludin mRNA levels in both wild-type and LDLr-/-mice treated with a hypercholesterolemic diet. The LDLr-/-mice fed with a regular diet already presented BBB dysfunction. The BBB-increased leakage in the hippocampi of LDLr-/-mice was related to high microvessel content and intense astrogliosis, which did not occur in the control mice. CONCLUSION: Therefore, LDLr-/-mice seem to be more susceptible to cognitive impairments and BBB damage induced by exposure to a high cholesterol diet. Finally, BBB disruption appears to be a relevant event in hypercholesterolemia-induced brain alterations.

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Monogenic familial hypercholesterolemia is characterized by impaired cellular uptake of apolipoprotein B containing lipoproteins. However, its consequences on whole-body cholesterol metabolism are unclear. We investigated cholesterol metabolism in wild-type mice (control) and in knockout (KO) mice for the low-density lipoprotein receptor (LDLR-KO) and for apolipoprotein E (apoE-KO) containing the genetic basis of the C57BL/6J mice, under a cholesterol-free diet. Cholesterol and "non-cholesterol" sterols (cholestanol, desmosterol, and lathosterol) were measured in plasma, tissues, as well as in feces as cholesterol and its bacterial modified products (neutral sterols) using gas chromatography/mass spectrometry, and bile acids were measured by an enzymatic method. Compared to controls, LDLR-KO mice have elevated plasma and whole-body cholesterol concentrations, but total fecal sterols are not modified, characterizing unaltered body cholesterol synthesis together with impaired body cholesterol excretion. ApoE-KO mice presented the highest concentrations of plasma cholesterol, whole-body cholesterol, cholestanol, total fecal sterols, and cholestanol, compatible with high cholesterol synthesis rate; the latter seems attributed to elevated body desmosterol (Bloch cholesterol synthesis pathway). Nonetheless, whole-body lathosterol (Kandutsch-Russel cholesterol synthesis pathway) decreased in both KO models, likely explaining the diminished fecal bile acids. We have demonstrated for the first time quantitative changes of cholesterol metabolism in experimental mouse models that explain differences between LDLR-KO and apoE-KO mice. These findings contribute to elucidate the metabolism of cholesterol in human hypercholesterolemia of genetic origin.

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BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant disease characterized by an increased LDL-cholesterol (LDLc) serum concentration and premature cardiovascular disease. Screening of small populations where at least one homozygous (HoFH) patient has been identified may be a proper approach for detecting FH patients. Previously, we reported an HoFH patient carrying the mutation p.Asp360His LDLR, who was born in the Mexican community El Triunfo (Quimixtlan, Puebla). AIM OF THE STUDY: To identify patients with familial hypercholesterolemia in the community El Triunfo and to describe their clinical and biochemical characteristics. METHODS: We studied 308 individuals by quantifying lipid levels and by DNA sequencing. RESULTS: Sixteen of 308 individuals presented an LDLc level >170 mg/dL and all of them turned out to be heterozygous for the LDLR p.Asp360His variant. Subsequently, 34 of their first-degree relatives (mainly siblings and parents) were genotyped rendering six additional HeFH patients, which resulted in 22 carriers of the mutated allele. The study of six LDLR polymorphisms in four unrelated individuals from the community (one HoFH and three HeFH) showed the same haplotype combination, suggesting a unique ancestral origin of the mutation. CONCLUSIONS: The community El Triunfo, has the highest worldwide frequency ever reported of HeFH, with 7.14% (22/308, equivalent to 1/14 inhabitants). Since the HeFH patients showed variable biochemical expression, we suggest looking for factors with the potential to modify the phenotype. Finally, we stress the importance of establishing accurate LDLc cut-off points applicable to Mexican population for the diagnosis of FH.

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Familial hypercholesterolemia (FH) is a genetic disorder caused by dysfunction of low density lipoprotein receptors (LDLr), resulting in elevated plasma cholesterol levels. FH patients frequently exhibit cognitive impairment, a finding recapitulated in LDLr deficient mice (LDLr-/-), an animal model of FH. In addition, LDLr-/- mice are more vulnerable to the deleterious memory impact of amyloid-ß (Aß), a peptide linked to Alzheimer's disease. Here, we investigated whether the expression of proteins involved in Aß metabolism are altered in the brains of adult or middle-aged LDLr-/- mice. After spatial memory assessment, Aß levels and gene expression of LDLr related-protein 1, proteins involved in Aß synthesis, and apoptosis-related proteins were evaluated in prefrontal cortex and hippocampus. Moreover, the location and cell-specificity of apoptosis signals were evaluated. LDLr-/- mice presented memory impairment, which was more severe in middle-aged animals. Memory deficit in LDLr-/- mice was not associated with altered expression of proteins involved in Aß processing or changes in Aß levels in either hippocampus or prefrontal cortex. We further found that the expression of Bcl-2 was reduced while the expression of Bax was increased in both prefrontal cortex and hippocampus in 3- and 14-month-old LDLr-/-mice Finally, LDLr-/- mice presented increased immunoreactivity for activated caspase-3 in the prefrontal cortex and hippocampus. The activation of caspase 3 was predominantly associated with neurons in LDLr-/- mice. Cognitive impairment in LDLr-/- mice is thus accompanied by an exacerbation of neuronal apoptosis in brain regions related to memory formation, but not by changes in Aß processing or levels.

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The aim of the study was to evaluate the effect of an anabolic steroid, stanozolol, in a model of atherosclerosis and to investigate the involvement of the modulation of the inflammatory cytokines and oxidative stress in vascular lipid deposition. Low-density lipid receptor-deficient (LDLr-/-) mice were fed a standard chow diet and were each week injected subcutaneously either saline (control C group) or 20 mg/kg stanozolol (S group). After 8 weeks, the levels of cholesterol, oxidized LDL (OxLDL) and cytokines were measured in plasma, lipid deposition in aorta was evaluated by en face analysis, and thiobarbituric acid-reactive substances and oxidation protein were determined in liver. The S group demonstrated increases in vascular lipid deposition, triglycerides and non-HDL cholesterol levels. Stanozolol increased tumour necrosis factor alpha (TNF-α) and decreased interleukin-10 as well as increased the TNF-α/IL-10 ratio. Furthermore, oxidative stress was observed in the S group, as indicated by an increase in the plasma OxLDL, as well as by lipid peroxidation and oxidation of proteins in the liver. Chronic treatment with stanozolol promoted lipid deposition in the LDLr-/- mice that could be attributed to a modification of the circulating cytokine levels and systemic oxidative stress. Our results suggest that the anabolic steroid stanozolol in the absence of functional LDL receptors by increasing systemic inflammation and oxidative stress may increase the risk of development and progression of atherosclerosis.

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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

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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

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