Homozygous Familial Hypercholesterolemia Nohara, Atsushi; Tada, Hayato; Ogura, Masatsune ...
Journal of Atherosclerosis and Thrombosis,
07/2021, Volume:
28, Issue:
7
Journal Article
Open access
Familial hypercholesterolemia (FH) is an inherited disorder with retarded clearance of plasma LDL caused by mutations of the genes involved in the LDL receptor-mediated pathway and most of them ...exhibit autosomal dominant inheritance. Homozygotes of FH (HoFH) may have plasma LDL-C levels, which are at least twice as high as those of heterozygous FH (HeFH) and therefore four times higher than normal levels. Prevalence of HoFH had been estimated as 1 in 1,000,000 before but more recent genetic analysis surveys predict 1 in 170,000 to 300,000. Since LDL receptor activity is severely impaired, HoFH patients do not or very poorly respond to medications to enhance activity, such as statins, and have a poorer prognosis compared to HeFH. HoFH should therefore be clinically distinguished from HeFH. Thorough family studies and genetic analysis are recommended for their accurate diagnosis.Fatal cardiovascular complications could develop even in the first decade of life for HoFH, so aggressive lipid-lowering therapy should be initiated as early as possible. Direct removal of plasma LDL by lipoprotein apheresis has been the principal measure for these patients. However, this treatment alone may not achieve stable LDL-C target levels and combination with drugs should be considered. The lipid-lowering effects of statins and PCSK9 inhibitors substantially vary depending on the remaining LDL receptor activity of individual patients. On the other hand, the action an MTP inhibitor is independent of LDL receptor activity, and it is effective in most HoFH cases.This review summarizes the key clinical issues of HoFH as well as insurance coverage available under the Japanese public healthcare system.
Abstract Atherosclerosis is a chronic inflammatory disease of the arterial wall. It is characterized by subendothelial accumulation of low-density lipoprotein cholesterol, and its subsequent ...modification at athero-prone areas leads to further activation of the vascular wall and maintains vascular inflammation. An entirely new level of post-transcriptional gene regulation through microRNA (miR) expression has emerged recently as an important mechanism in the development and progression of numerous diseases, including atherosclerosis. Recently, miR-33a/b have been shown to act as post-transcriptional regulators of lipid metabolism, and their pharmacological inhibition diminished atherosclerosis by raising plasma high-density lipoprotein levels. This review summarizes the current understanding of the functions of miR-33a/b and the progress in miRNA therapeutics for treatment of various diseases, including atherosclerosis.
MicroRNAs (miRNAs) are a class of small noncoding RNAs that have gained status as important regulators of gene expression. Recent studies have demonstrated that miRNAs are aberrantly expressed in the ...cardiovascular system under some pathological conditions. Gain- and loss-of-function studies using in vitro and in vivo models have revealed distinct roles for specific miRNAs in cardiovascular development and physiological function. The implications of miRNAs in cardiovascular disease have recently been recognized, representing the most rapidly evolving research field. In the present minireview, the current relevant findings on the role of miRNAs in cardiac diseases are updated and the target genes of these miRNAs are summarized.
Tangier disease is a genetic disorder characterized by an absence or extremely low level of high-density lipoprotein (HDL)-cholesterol (HDL-C). It is caused by a dysfunctional mutation of the ...ATP-binding cassette transporter A1 (ABCA1) gene, the mandatory gene for generation of HDL particles from cellular cholesterol and phospholipids, and it appears in an autosomal recessive hereditary profile. To date, 35 cases have been reported in Japan and 109 cases outside Japan. With dysfunctional mutations in both alleles (homozygotes or compound heterozygotes), the HDL-C level is mostly less than 5 mg/dL and there is 10 mg/dL or less of apolipoprotein A-I (apoA-I), the major protein component of HDL. In patients with Tangier disease, major physical findings are orange-colored pharyngeal tonsils, hepatosplenomegaly, corneal opacity, lymphadenopathy, and peripheral neuropathy. Although patients tend to have decreased low-density lipoprotein (LDL)-cholesterol (LDL-C) levels, premature coronary artery disease is frequently observed. No specific curative treatment is currently available, so early identification of patients and preventing atherosclerosis development are crucial. Management of risk factors other than low HDL-C is also important, such as LDL-C levels, hypertension and smoking. Additionally, treatment for glucose intolerance might be required because impaired insulin secretion from pancreatic beta cells has occasionally been reported.
Protein-coding genes account for less than 2% of the whole genome. However, the advances in RNA sequencing and genome-wide analysis have demonstrated that most of the genome is capable of being ...transcribed. Moreover, recent studies have suggested that long non-coding RNAs (lncRNAs) are critical regulators of gene expression and epigenesis in both physiological and disease states. Several lncRNAs are functionally involved in cardiovascular diseases and may be potential therapeutic targets. Here, we review the current strategies for the discovery of functional lncRNAs and recently discovered lncRNAs in the cardiovascular field, focusing on cardiac development, hypertrophy, heart failure, and atherosclerosis. We also discuss the therapeutic potentials of synthetic RNAs to modulate these lncRNAs and future directions in this research field.
The high controlling nutritional status (CONUT) score that represents poor nutritional status has been acknowledged to have prognostic implications in chronic heart failure. We aimed to investigate ...its role in acute decompensated heart failure (ADHF). Using the data from an multicenter registry that enrolled 4056 consecutive patients hospitalized for ADHF in Japan between 2014 and 2016, we analyzed 2466 patients in whom data on the components of the CONUT score at hospital presentation were available. The decrease of lymphocyte count and total cholesterol was assigned with 0, 1, 2, and 3 points and the decrease of albumin was assigned with 0, 2, 4, and 6 points according to the severity. We defined low CONUT score as 0-4 (N = 1568) and high CONUT score as 5-9 (N = 898). The patients in the high CONUT score group were older and more likely to have a smaller body mass index than those in the low CONUT score group. The high CONUT score group was associated with higher rate of death and infection during the index hospitalization compared to the low CONUT score group (9.0% versus 4.4%, and 21.9% versus 12.7%, respectively). After adjusting for confounders, the excess risk of high relative to low CONUT score for mortality and infection was significant (OR: 1.61, 95%CI: 1.05-2.44, and OR: 1.66, 95%CI: 1.30-2.12, respectively). The effect was incremental according to the score. High CONUT score was associated with higher risk for in-hospital mortality and infection in an incremental manner in patients hospitalized for ADHF.
The Cre-LoxP system has been commonly used for cell-specific genetic manipulation. However, many Cre strains exhibit excision activity in unexpected cell types or tissues. Therefore, it is important ...to identify the cell types in which recombination takes place. Fibroblasts are a cell type that is inadequately defined due to a lack of specific markers to detect the entire cell lineage. Here, we investigated the Cre recombination induced by Col1α2-iCre, one of the most common fibroblast-mesenchymal Cre driver lines, by using a double-fluorescent Cre reporter line in which GFP is expressed when recombination occurs. Our results indicated that Col1α2-iCre activity was more extensive across cell types than previously reported: Col1α2-iCre-mediated recombination was found in not only cells of mesenchymal origin but also those of other lineages, including haematopoietic cells, myocardial cells, lung and intestinal epithelial cells, and neural cells. In addition, study of embryos revealed that recombination by Col1α2-iCre was observed in the early developmental stage before gastrulation in epiblasts, which would account for the recombination across various cell types in adult mice. These results offer more insights into the activity of Col1α2-iCre and suggest that experimental results obtained using Col1α2-iCre should be carefully interpreted.
In some patients with type 2 diabetes mellitus (DM) without hypertension, cardiac hypertrophy and attenuated cardiac function are observed, and this insult is termed diabetic cardiomyopathy. To date, ...microRNA (miRNAs or miR) functions in diabetic cardiomyopathy remain to be elucidated.
To clarify the functions of miRNAs involved in diabetic cardiomyopathy caused by type 2 DM.
C57BL/6 mice were fed a high-fat diet (HFD) for 20 weeks, which induced obesity and type 2 DM. miRNA microarray analyses and real-time polymerase chain reaction revealed that miR-451 levels were significantly increased in the type 2 DM mouse hearts. Because excess supply of saturated fatty acids is a cause of diabetic cardiomyopathy, we stimulated neonatal rat cardiac myocytes with palmitic acid and confirmed that miR-451 expression was increased in a dose- and time-dependent manner. Loss of miR-451 function ameliorated palmitate-induced lipotoxicity in neonatal rat cardiac myocytes. Calcium-binding protein 39 (Cab39) is a scaffold protein of liver kinase B1 (LKB1), an upstream kinase of AMP-activated protein kinase (AMPK). Cab39 was a direct target of miR-451 in neonatal rat cardiac myocytes and Cab39 overexpression rescued the lipotoxicity. To clarify miR-451 functions in vivo, we generated cardiomyocyte-specific miR-451 knockout mice. HFD-induced cardiac hypertrophy and contractile reserves were ameliorated in cardiomyocyte-specific miR-451 knockout mice compared with control mice. Protein levels of Cab39 and phosphorylated AMPK were increased and phosphorylated mammalian target of rapamycin (mTOR) was reduced in cardiomyocyte-specific miR-451 knockout mouse hearts compared with control mouse hearts.
Our results demonstrate that miR-451 is involved in diabetic cardiomyopathy through suppression of the LKB1/AMPK pathway.
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