The acyltransferase LCAT mediates FA esterification of plasma cholesterol. In vitro studies have shown that LCAT also FA-esterifies several oxysterols, but in vivo evidence is lacking. Here, we measured both free and FA-esterified forms of sterols in 206 healthy volunteers and 8 individuals with genetic LCAT deficiency, including familial LCAT deficiency (FLD) and fish-eye disease (FED).
View Article and Find Full Text PDFBackground: The risk of cardiovascular disease and mortality in salt-sensitive patients with diabetes mellitus and uncontrolled nocturnal hypertension is high. The SACRA (Sodium-Glucose Cotransporter 2 [SGLT2] Inhibitor and Angiotensin Receptor Blocker [ARB] Combination Therapy in Patients With Diabetes and Uncontrolled Nocturnal Hypertension) study investigated changes in blood pressure (BP) with empagliflozin plus existing antihypertensive therapy.
Methods: This multicenter, double-blind, parallel study was conducted in Japan.
Objective- Inhibition of HMGCR (3-hydroxy-3-methylglutaryl-coenzyme A reductase) is atheroprotective primarily by decreasing plasma LDL (low-density lipoprotein)-cholesterol. However, it is unknown whether inhibition of HMGCR in myeloid cells contributes to this atheroprotection. We sought to determine the role of myeloid HMGCR in the development of atherosclerosis.
View Article and Find Full Text PDFAim: Myriad biological effects of leptin may lead to broad therapeutic applications for various metabolic diseases, including diabetes and its complications; however, in contrast to its anorexic effect, the molecular mechanisms underlying adipopenic and glucose-lowering effects of leptin have not been fully understood. Here we aim to clarify the role of hormone-sensitive lipase (HSL) in leptin's action.
Methods: Wild-type (WT) and HSL-deficient (HSLKO) mice were made hyperleptinemic by two commonly-used methods: adenovirus-mediated overexpression of leptin and continuous subcutaneous infusion of leptin by osmotic pumps.
Squalene synthase (SS) catalyzes the biosynthesis of squalene, the first specific intermediate in the cholesterol biosynthetic pathway. To test the feasibility of lowering plasma cholesterol by inhibiting hepatic SS, we generated mice in which SS is specifically knocked out in the liver (L-SSKO) using Cre-loxP technology. Hepatic SS activity of L-SSKO mice was reduced by >90%.
View Article and Find Full Text PDFAn excess of cholesterol and/or oxysterols induces apoptosis in macrophages, contributing to the development of advanced atherosclerotic lesions. In foam cells, these sterols are stored in esterified forms, which are hydrolyzed by two enzymes: neutral cholesterol ester hydrolase 1 (Nceh1) and hormone-sensitive lipase (Lipe). A deficiency in either enzyme leads to accelerated growth of atherosclerotic lesions in mice.
View Article and Find Full Text PDFHydrolysis of intracellular cholesteryl ester (CE) is the rate-limiting step in the efflux of cholesterol from macrophage foam cells. In mouse peritoneal macrophages (MPMs), this process is thought to involve several enzymes: hormone-sensitive lipase (Lipe), carboxylesterase 3 (Ces3), neutral CE hydrolase 1 (Nceh1). However, there is some disagreement over the relative contributions of these enzymes.
View Article and Find Full Text PDFPostprandial hyperglycemia and/or hyperlipidemia can contribute to development of atherosclerosis in patients with type 2 diabetes mellitus (T2DM). The objective of this study was to compare the effects of miglitol and sitagliptin on postprandial glucose and lipid metabolism in patients with T2DM. Thirty-five patients with T2DM were randomized to 2 groups receiving miglitol (150 mg/day) or sitagliptin (50 mg/day).
View Article and Find Full Text PDFJ Atheroscler Thromb
December 2013
Aim: Familial apolipoprotein C-II (apoC-II) deficiency is a rare autosomal recessive disorder with marked hypertriglyceridemia resulting from impaired activation of lipoprotein lipase. In most cases of apoC-II deficiency, causative mutations have been found in the protein-coding region of APOC2; however, several atypical cases of apoC-II deficiency were reported to have markedly reduced, but detectable levels of plasma apoC-II protein (hereafter referred to as hypoapoC-II), which resulted from decreased promoter activity or improper splicing of apoC-II mRNA due to homozygous mutations in APOC2. Here we aim to dissect the molecular bases of a new case of hypoapoC-II.
View Article and Find Full Text PDFThe role of macrophage lipoprotein lipase (LpL) in the development of atherosclerosis and adiposity was examined in macrophage LpL knockout (MLpLKO) mice. MLpLKO mice were generated using cre-loxP gene targeting. Loss of LpL in macrophages did not alter plasma LpL activity or lipoprotein levels.
View Article and Find Full Text PDFBackground: There are very few clinical reports that have compared the association between cigarette smoking and microangiopathy in Asian patients with type 1 diabetes mellitus (T1DM). The objective of this study was to assess the relationships between urinary protein concentrations and smoking and gender-based risk factors among patients with T1DM.
Methods: A cross-sectional study of 259 patients with T1DM (men/women = 90/169; mean age, 50.
To address the effects of ezetimibe on high-density lipoprotein (HDL) metabolism, the HDL subclasses, cholesteryl ester transfer protein (CETP), and lecithin-cholesterol acyltransferase (LCAT) were measured in patients with type 2 diabetes mellitus (T2DM). Twenty-three hypercholesterolemic patients with T2DM were treated with 10 mg of ezetimibe daily for 12 weeks. Plasma total cholesterol (TC), low-density lipoprotein (LDL)-cholesterol (C), HDL-C, HDL(2)-C, HDL(3)-C, CETP mass, and LCAT activity were measured.
View Article and Find Full Text PDFObjective: 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) catalyzes the rate-limiting step in cholesterol biosynthesis and has proven to be an effective target of lipid-lowering drugs, statins. The aim of this study was to understand the role of hepatic HMGCR in vivo.
Methods And Results: To disrupt the HMGCR gene in liver, we generated mice homozygous for a floxed HMGCR allele and heterozygous for a transgene encoding Cre recombinase under the control of the albumin promoter (liver-specific HMGCR knockout mice).
The combination of pegylated interferon-α2b (PEG-IFNα) and ribavirin (RBV) is a standard treatment for chronic hepatitis C. The case of a patient with chronic hepatitis C who developed Hashitoxicosis followed by type 1 diabetes mellitus (T1DM) with PEG-IFNα plus RBV combination therapy, but not IFNα alone, is presented.
View Article and Find Full Text PDFOverexpression of sterol regulatory element-binding protein-1c (SREBP-1c) in β cells causes impaired insulin secretion and β cell dysfunction associated with diminished pancreatic duodenal homeodomain transcription factor-1 (PDX-1) expression in vitro and in vivo. To identify the molecular mechanism responsible for this effect, the mouse Pdx-1 gene promoter (2.7 kb) was analyzed in β cell and non-β cell lines.
View Article and Find Full Text PDFLecithin-cholesterol acyltransferase (LCAT) is an important enzyme involved in the esterification of cholesterol. Here, we report a novel point mutation in the LCAT gene of a 63-year-old female with characteristics of classic familial LCAT deficiency. The patient's clinical manifestations included corneal opacity, mild anemia, mild proteinuria and normal renal function.
View Article and Find Full Text PDFJ Atheroscler Thromb
September 2011
Cholesterol ester-laden macrophage foam cells are a hallmark of atherosclerosis. The cycle of esterification and hydrolysis of cholesterol esters is one of the key steps in macrophage cholesterol trafficking. In the process of foam cell formation, excess free cholesterol undergoes esterification by acyl coenzyme A: acylcholesterol transferase 1 (ACAT-1), and fatty acid sterol esters are stored in cytoplasmic lipid droplets.
View Article and Find Full Text PDFBiochem Biophys Res Commun
January 2011
We have previously demonstrated that neutral cholesterol ester hydrolase 1 (Nceh1) regulates foam cell formation and atherogenesis through the catalytic activity of cholesterol ester hydrolysis, and that Nceh1 and hormone-sensitive lipase (Lipe) are responsible for the majority of neutral cholesterol ester hydrolase activity in macrophages. There are several cholesterol ester-metabolizing tissues and cells other than macrophages, among which adrenocortical cells are also known to utilize the intracellular cholesterol for steroidogenesis. It has been believed that the mobilization of intracellular cholesterol ester in adrenal glands was facilitated solely by Lipe.
View Article and Find Full Text PDFA 59-year-old female with type 1 diabetes and RS3PE had HLA types known to be associated with both diseases. Type 1 diabetes patients suffering from polyarthritis and pitting edema should be examined for possible RS3PE and glucocorticoid therapy may be indicated despite the diabetes.
View Article and Find Full Text PDFRationale: Hydrolysis of intracellular cholesterol ester (CE) is the key step in the reverse cholesterol transport in macrophage foam cells. We have recently shown that neutral cholesterol ester hydrolase (Nceh)1 and hormone-sensitive lipase (Lipe) are key regulators of this process in mouse macrophages. However, it remains unknown which enzyme is critical in human macrophages and atherosclerosis.
View Article and Find Full Text PDFTo date, there are very few clinical reports that have compared the effects of ezetimibe on lipid parameters between hypercholesterolemic patients with and without type 2 diabetes mellitus (T2DM). In this study, we recruited patients for hypercholesterolemic groups with T2DM (n = 42; men/women = 24/18; HbA1c = 6.7 ± 5.
View Article and Find Full Text PDFSterol regulatory element-binding protein (SREBP)-1 is a key transcription factor for the regulation of lipogenic enzyme genes in the liver. Polyunsaturated fatty acids (PUFA) selectively suppress hepatic SREBP-1, but molecular mechanisms remain largely unknown. To gain insight into this regulation, we established in vivo reporter assays to assess the activities of Srebf1c transcription and proteolytic processing.
View Article and Find Full Text PDFCholesterol ester (CE)-laden macrophage foam cells are the hallmark of atherosclerosis, and the hydrolysis of intracellular CE is one of the key steps in foam cell formation. Although hormone-sensitive lipase (LIPE) and cholesterol ester hydrolase (CEH), which is identical to carboxylsterase 1 (CES1, hCE1), were proposed to mediate the neutral CE hydrolase (nCEH) activity in macrophages, recent evidences have suggested the involvement of other enzymes. We have recently reported the identification of a candidate, neutral cholesterol ester hydrolase 1(Nceh1).
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