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Abstract
Postprandial hyperlipidaemia is an important feature of diabetic dyslipidaemia and plays an important role in the development of cardiovascular disease in individuals with type 2 diabetes. Postprandial hyperlipidaemia in type 2 diabetes is secondary to increased chylomicron production by the enterocytes and delayed catabolism of chylomicrons and chylomicron remnants. Insulin and some intestinal hormones (e.g. glucagon-like peptide-1 [GLP-1]) influence intestinal lipid metabolism. In individuals with type 2 diabetes, insulin resistance and possibly reduced GLP-1 secretion are involved in the pathophysiology of postprandial hyperlipidaemia. Several factors are involved in the overproduction of chylomicrons: (1) increased expression of microsomal triglyceride transfer protein, which is a key enzyme in chylomicron synthesis; (2) higher stability and availability of apolipoprotein B-48; and (3) increased de novo lipogenesis. Individuals with type 2 diabetes present with disorders of cholesterol metabolism in the enterocytes with reduced absorption and increased synthesis. The increased production of chylomicrons in type 2 diabetes is also associated with a reduction in their catabolism, mostly because of a reduction in activity of lipoprotein lipase. Modification of the microbiota, which is observed in type 2 diabetes, may also generate disorders of intestinal lipid metabolism, but human data remain limited. Some glucose-lowering treatments significantly influence intestinal lipid absorption and transport. Postprandial hyperlipidaemia is reduced by metformin, pioglitazone, alpha-glucosidase inhibitors, dipeptidyl peptidase 4 inhibitors and GLP-1 agonists. The most pronounced effect is observed with GLP-1 agonists, which reduce chylomicron production significantly in individuals with type 2 diabetes and have a direct effect on the intestine by reducing the expression of genes involved in intestinal lipoprotein metabolism. The effect of sodium-glucose cotransporter 2 inhibitors on intestinal lipid metabolism needs to be clarified.
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Affiliation(s)
- Bruno Vergès
- Endocrinology-Diabetology Department, University-Hospital, Dijon, France.
- Inserm UMR 1231, Medical School, University of Burgundy-Franche Comté, Dijon, France.
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2
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Cook JR, Kohan AB, Haeusler RA. An Updated Perspective on the Dual-Track Model of Enterocyte Fat Metabolism. J Lipid Res 2022; 63:100278. [PMID: 36100090 PMCID: PMC9593242 DOI: 10.1016/j.jlr.2022.100278] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/08/2022] [Accepted: 08/31/2022] [Indexed: 02/04/2023] Open
Abstract
The small intestinal epithelium has classically been envisioned as a conduit for nutrient absorption, but appreciation is growing for a larger and more dynamic role for enterocytes in lipid metabolism. Considerable gaps remain in our knowledge of this physiology, but it appears that the enterocyte's structural polarization dictates its behavior in fat partitioning, treating fat differently based on its absorption across the apical versus the basolateral membrane. In this review, we synthesize existing data and thought on this dual-track model of enterocyte fat metabolism through the lens of human integrative physiology. The apical track includes the canonical pathway of dietary lipid absorption across the apical brush-border membrane, leading to packaging and secretion of those lipids as chylomicrons. However, this track also reserves a portion of dietary lipid within cytoplasmic lipid droplets for later uses, including the "second-meal effect," which remains poorly understood. At the same time, the enterocyte takes up circulating fats across the basolateral membrane by mechanisms that may include receptor-mediated import of triglyceride-rich lipoproteins or their remnants, local hydrolysis and internalization of free fatty acids, or enterocyte de novo lipogenesis using basolaterally absorbed substrates. The ultimate destinations of basolateral-track fat may include fatty acid oxidation, structural lipid synthesis, storage in cytoplasmic lipid droplets, or ultimate resecretion, although the regulation and purposes of this basolateral track remain mysterious. We propose that the enterocyte integrates lipid flux along both of these tracks in order to calibrate its overall program of lipid metabolism.
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Affiliation(s)
- Joshua R. Cook
- Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, USA,Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Alison B. Kohan
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rebecca A. Haeusler
- Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, USA,Department of Pathology and Cell Biology; Columbia University College of Physicians and Surgeons, New York, NY, USA,For correspondence: Rebecca A. Haeusler
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3
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Rauzier C, Lamarche B, Tremblay AJ, Couture P, Picard F. Associations between Insulin-Like Growth Factor Binding Protein-2 and lipoprotein kinetics in men. J Lipid Res 2022; 63:100269. [PMID: 36030928 PMCID: PMC9587400 DOI: 10.1016/j.jlr.2022.100269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 08/12/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
Low circulating concentrations of insulin-like growth factor binding protein-2 (IGFBP-2) have been associated with dyslipidemia, notably with high triglyceride (TG) levels. However, the determinants by which IGFBP-2 influences lipoprotein metabolism, especially that of TG-rich lipoproteins (TRLs), are poorly understood. Here, we aimed to assess the relationships between IGFBP-2 levels and lipoprotein production and catabolism in human subjects. Fasting IGFBP-2 concentrations were measured in the plasma of 219 men pooled from previous lipoprotein kinetics studies. We analyzed production rate and fractional catabolic rates of TRLapoB-48, and LDL-, IDL-, and VLDLapoB-100 by multicompartmental modeling of l-[5,5,5-D3] leucine enrichment data after a 12 h primed constant infusion in individuals kept in a constant nutritional steady state. Subjects had an average BMI of 30 kg/m2, plasma IGFBP-2 levels of 157 ng/ml, and TG of 2.2 mmol/l. After adjustments for age and BMI, IGFBP-2 levels were negatively associated with plasma TG (r = −0.29; P < 0.0001) and positively associated with HDL-cholesterol (r = 0.26; P < 0.0001). In addition, IGFBP-2 levels were positively associated with the fractional catabolic rate of VLDLapoB-100 (r = 0.20; P < 0.01) and IDLapoB-100 (r = 0.19; P < 0.05) and inversely with the production rate of TRLapoB-48 (r = −0.28; P < 0.001). These correlations remained statistically significant after adjustments for age, BMI, and the amount of fat given during the tracer infusion. These findings show that the association between low plasma IGFBP-2 and high TG concentrations could be due to both an impaired clearance of apoB-100-containing VLDL and IDL particles and an increased production of apoB-48-containing chylomicrons. Additional studies are necessary to investigate whether and how IGFBP-2 directly impacts the kinetics of TRL.
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Affiliation(s)
- Chloé Rauzier
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec - Université Laval, Québec, QC, Canada; Faculté de pharmacie, Université Laval, Québec, QC, Canada
| | - Benoît Lamarche
- Centre Nutrition, santé et société (NUTRISS), Institut sur la nutrition et les aliments fonctionnels (INAF), Université Laval, Québec, QC, Canada; École de nutrition, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, QC, Canada
| | - André J Tremblay
- Centre Nutrition, santé et société (NUTRISS), Institut sur la nutrition et les aliments fonctionnels (INAF), Université Laval, Québec, QC, Canada; École de nutrition, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, QC, Canada
| | - Patrick Couture
- Centre Nutrition, santé et société (NUTRISS), Institut sur la nutrition et les aliments fonctionnels (INAF), Université Laval, Québec, QC, Canada; Département de médecine, Faculté de médecine, Université Laval, Québec, QC, Canada
| | - Frédéric Picard
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec - Université Laval, Québec, QC, Canada; Faculté de pharmacie, Université Laval, Québec, QC, Canada.
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Genetic reprogramming of remnant duodenum may contribute to type 2 diabetes improvement after Roux en-Y gastric bypass. Nutrition 2022; 99-100:111631. [DOI: 10.1016/j.nut.2022.111631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 12/31/2021] [Accepted: 02/07/2022] [Indexed: 11/22/2022]
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Jacome-Sosa M, Hu Q, Manrique-Acevedo CM, Phair RD, Parks EJ. Human intestinal lipid storage through sequential meals reveals faster dinner appearance is associated with hyperlipidemia. JCI Insight 2021; 6:e148378. [PMID: 34369385 PMCID: PMC8489663 DOI: 10.1172/jci.insight.148378] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 06/30/2021] [Indexed: 12/14/2022] Open
Abstract
Background It is increasingly recognized that intestinal cells can store lipids after a meal, yet the effect of this phenomenon on lipid absorption patterns in insulin resistance remains unknown. Methods The kinetics of meal fat appearance were measured in insulin-sensitive (IS, n = 8) and insulin-resistant (IR, n = 8) subjects after sequential, isotopically labeled lunch and dinner meals. Plasma dynamics on triacylglycerol-rich (TAG-rich) lipoproteins and plasma hormones were analyzed using a nonlinear, non–steady state kinetic model. Results At the onset of dinner, IS subjects showed an abrupt plasma appearance of lunch lipid consistent with the “second-meal effect,” followed by slower appearance of dinner fat in plasma, resulting in reduced accumulation of dinner TAG of 48% compared with lunch. By contrast, IR subjects exhibited faster meal TAG appearance rates after both lunch and dinner. This effect of lower enterocyte storage between meals was associated with greater nocturnal and next-morning hyperlipidemia. The biochemical data and the kinetic analysis of second-meal effect dynamics are consistent with rapid secretion of stored TAG bypassing lipolysis and resynthesis. In addition, the data are consistent with a role for the diurnal pattern of plasma leptin in regulating the processing of dietary lipid. Conclusion These data support the concept that intestinal lipid storage may be physiologically beneficial in IS subjects. Trial registration ClinicalTrials.gov NCT02020343. Funding This study was supported by a grant from the American Diabetes Association (grant 1-13-TS-12).
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Affiliation(s)
| | - Qiong Hu
- Department of Nutrition and Exercise Physiology and
| | | | - Robert D Phair
- Integrative Bioinformatics, Inc., Mountain View, California, USA
| | - Elizabeth J Parks
- Department of Nutrition and Exercise Physiology and.,Division of Gastroenterology and Hepatology, School of Medicine, University of Missouri, Columbia, Missouri, USA
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Mucinski JM, Vena JE, Ramos-Roman MA, Lassman ME, Szuszkiewicz-Garcia M, McLaren DG, Previs SF, Shankar SS, Parks EJ. High-throughput LC-MS method to investigate postprandial lipemia: considerations for future precision nutrition research. Am J Physiol Endocrinol Metab 2021; 320:E702-E715. [PMID: 33522396 DOI: 10.1152/ajpendo.00526.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Elevated postprandial lipemia is an independent risk factor for cardiovascular disease, yet methods to quantitate postmeal handling of dietary lipids in humans are limited. This study tested a new method to track dietary lipid appearance using a stable isotope tracer (2H11-oleate) in liquid meals containing three levels of fat [low fat (LF), 15 g; moderate fat (MF), 30 g; high fat (HF), 60 g]. Meals were fed to 12 healthy men [means ± SD, age 31.3 ± 9.2 yr, body mass index (BMI) 24.5 ± 1.9 kg/m2] during four randomized study visits; the HF meal was administered twice for reproducibility. Blood was collected over 8 h postprandially, triglyceride (TG)-rich lipoproteins (TRL), and particles with a Svedberg flotation rate >400 (Sf > 400, n = 8) were isolated by ultracentrifugation, and labeling of two TG species (54:3 and 52:2) was quantified by LC-MS. Total plasma TRL-TG concentrations were threefold greater than Sf > 400-TG. Both Sf > 400- and TRL-TG 54:3 were present at higher concentrations than 52:2, and singly labeled TG concentrations were higher than doubly labeled. Furthermore, TG 54:3 and the singly labeled molecules demonstrated higher plasma absolute entry rates differing significantly across fat levels within a single TG species (P < 0.01). Calculation of fractional entry showed no significant differences in label handling supporting the utility of either TG species for appearance rate calculations. These data demonstrate the utility of labeling research meals with stable isotopes to investigate human postprandial lipemia while simultaneously highlighting the importance of examining individual responses. Meal type and timing, control of prestudy activities, and effects of sex on outcomes should match the research goals. The method, optimized here, will be beneficial to conduct basic science research in precision nutrition and clinical drug development.NEW & NOTEWORTHY A novel method to test human intestinal lipid handling using stable isotope labeling is presented and, for the first time, plasma appearance and lipid turnover were quantified in 12 healthy men following meals with varying amounts of fat. The method can be applied to studies in precision nutrition characterizing individual response to support basic science research or drug development. This report discusses key questions for consideration in precision nutrition that were highlighted by the data.
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Affiliation(s)
- Justine M Mucinski
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Jennifer E Vena
- Alberta's Tomorrow Project, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada
| | - Maria A Ramos-Roman
- Division of Endocrinology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | | | | | | | | | | | - Elizabeth J Parks
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri School of Medicine, Columbia, Missouri
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Stahel P, Xiao C, Nahmias A, Lewis GF. Role of the Gut in Diabetic Dyslipidemia. Front Endocrinol (Lausanne) 2020; 11:116. [PMID: 32231641 PMCID: PMC7083132 DOI: 10.3389/fendo.2020.00116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/21/2020] [Indexed: 12/13/2022] Open
Abstract
Type 2 diabetes (T2D) is associated with increased risk of cardiovascular disease (CVD). In insulin resistant states such as the metabolic syndrome, overproduction and impaired clearance of liver-derived very-low-density lipoproteins and gut-derived chylomicrons (CMs) contribute to hypertriglyceridemia and elevated atherogenic remnant lipoproteins. Although ingested fat is the major stimulus of CM secretion, intestinal lipid handling and ultimately CM secretory rate is determined by numerous additional regulatory inputs including nutrients, hormones and neural signals that fine tune CM secretion during fasted and fed states. Insulin resistance and T2D represent perturbed metabolic states in which intestinal sensitivity to key regulatory hormones such as insulin, leptin and glucagon-like peptide-1 (GLP-1) may be altered, contributing to increased CM secretion. In this review, we describe the evidence from human and animal models demonstrating increased CM secretion in insulin resistance and T2D and discuss the molecular mechanisms underlying these effects. Several novel compounds are in various stages of preclinical and clinical investigation to modulate intestinal CM synthesis and secretion. Their efficacy, safety and therapeutic utility are discussed. Similarly, the effects of currently approved lipid modulating therapies such as statins, ezetimibe, fibrates, and PCSK9 inhibitors on intestinal CM production are discussed. The intricacies of intestinal CM production are an active area of research that may yield novel therapies to prevent atherosclerotic CVD in insulin resistance and T2D.
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Lalande C, Drouin-Chartier JP, Tremblay AJ, Couture P, Veilleux A. Plasma biomarkers of small intestine adaptations in obesity-related metabolic alterations. Diabetol Metab Syndr 2020; 12:31. [PMID: 32292494 PMCID: PMC7144049 DOI: 10.1186/s13098-020-00530-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 03/13/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Evidence suggests that pathophysiological conditions such as obesity and type 2 diabetes (T2D) are associated with morphologic and metabolic alterations in the small intestinal mucosa. Exploring these alterations generally requires invasive methods, limiting data acquisition to subjects with enteropathies or undergoing bariatric surgery. We aimed to evaluate small intestine epithelial cell homeostasis in a cohort of men covering a wide range of adiposity and glucose homoeostasis statuses. METHODS Plasma levels of citrulline, a biomarker of enterocyte mass, and I-FABP, a biomarker of enterocyte death, were measured by UHPLC‑MS and ELISA in 154 nondiabetic men and 67 men with a T2D diagnosis. RESULTS Plasma citrulline was significantly reduced in men with insulin resistance and T2D compared to insulin sensitive men. Decreased citrulline levels were, however, not observed in men with uncontrolled metabolic parameters during T2D. Plasma I-FABP was significantly higher in men with T2D, especially in presence of uncontrolled glycemic and lipid profile parameters. Integration of both parameters, which estimate enterocyte turnover, was associated with glucose homeostasis as well as with T2D diagnosis. Differences in biomarkers levels were independent of age and BMI and glucose filtration rates. CONCLUSIONS Our study supports a decreased functional enterocyte mass and an increased enterocyte death rate in presence of metabolic alterations but emphasizes that epithelial cell homeostasis is especially altered in presence of severe insulin resistance and T2D. The marked changes in small intestine cellularity observed in obesity and diabetes are thus suggested to be part of gut dysfunctions, mainly at an advanced stage of the disease.
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Affiliation(s)
- Catherine Lalande
- École de nutrition, Faculté des sciences de l’agriculture et de l’alimentation, Université Laval, 2440, boulevard Hochelaga, Québec, QC G1V 0A6 Canada
- Centre Nutrition, santé et société (NUTRISS), Institut sur la nutrition et les aliments fonctionnels (INAF), Université Laval, Québec, QC Canada
| | - Jean-Philippe Drouin-Chartier
- École de nutrition, Faculté des sciences de l’agriculture et de l’alimentation, Université Laval, 2440, boulevard Hochelaga, Québec, QC G1V 0A6 Canada
- Centre Nutrition, santé et société (NUTRISS), Institut sur la nutrition et les aliments fonctionnels (INAF), Université Laval, Québec, QC Canada
| | - André J. Tremblay
- Centre Nutrition, santé et société (NUTRISS), Institut sur la nutrition et les aliments fonctionnels (INAF), Université Laval, Québec, QC Canada
| | - Patrick Couture
- Centre Nutrition, santé et société (NUTRISS), Institut sur la nutrition et les aliments fonctionnels (INAF), Université Laval, Québec, QC Canada
- Centre des maladies lipidiques, Centre Hospitalier Universitaire (CHU) de Québec, Québec, QC Canada
| | - Alain Veilleux
- École de nutrition, Faculté des sciences de l’agriculture et de l’alimentation, Université Laval, 2440, boulevard Hochelaga, Québec, QC G1V 0A6 Canada
- Centre Nutrition, santé et société (NUTRISS), Institut sur la nutrition et les aliments fonctionnels (INAF), Université Laval, Québec, QC Canada
- Centre de Recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC Canada
- Canada Excellence Research Chair in the Microbiome-Endocannabinoidome Axis in Metabolic Health, Québec, QC Canada
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Xiao C, Stahel P, Carreiro AL, Hung YH, Dash S, Bookman I, Buhman KK, Lewis GF. Oral Glucose Mobilizes Triglyceride Stores From the Human Intestine. Cell Mol Gastroenterol Hepatol 2018; 7:313-337. [PMID: 30704982 PMCID: PMC6357697 DOI: 10.1016/j.jcmgh.2018.10.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 10/05/2018] [Accepted: 10/05/2018] [Indexed: 12/22/2022]
Abstract
BACKGROUND & AIMS The small intestine regulates plasma triglyceride (TG) concentration. Within enterocytes, dietary TGs are packaged into chylomicrons (CMs) for secretion or stored temporarily in cytoplasmic lipid droplets (CLDs) until further mobilization. We and others have shown that oral and intravenous glucose enhances CM particle secretion in human beings, however, the mechanisms through which this occurs are incompletely understood. METHODS Two separate cohorts of participants ingested a high-fat liquid meal and, 5 hours later, were assigned randomly to ingest either a glucose solution or an equivalent volume of water. In 1 group (N = 6), plasma and lipoprotein TG responses were assessed in a randomized cross-over study. In a separate group (N = 24), duodenal biopsy specimens were obtained 1 hour after ingestion of glucose or water. Ultrastructural and proteomic analyses were performed on duodenal biopsy specimens. RESULTS Compared with water, glucose ingestion increased circulating TGs within 30 minutes, mainly in the CM fraction. It decreased the total number of CLDs and the proportion of large-sized CLDs within enterocytes. We identified 2919 proteins in human duodenal tissue, 270 of which are related to lipid metabolism and 134 of which were differentially present in response to glucose compared with water ingestion. CONCLUSIONS Oral glucose mobilizes TGs stored within enterocyte CLDs to provide substrate for CM synthesis and secretion. Future studies elucidating the underlying signaling pathways may provide mechanistic insights that lead to the development of novel therapeutics for the treatment of hypertriglyceridemia.
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Affiliation(s)
- Changting Xiao
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Priska Stahel
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Alicia L. Carreiro
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana
| | - Yu-Han Hung
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana
| | - Satya Dash
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Ian Bookman
- Kensington Screening Clinic, Toronto, Ontario, Canada
| | - Kimberly K. Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana
| | - Gary F. Lewis
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada,Correspondence Address correspondence to: Gary F. Lewis, MD, FRCPC, Toronto General Hospital, 200 Elizabeth Street, EN12-218, Toronto, Ontario, M5G 2C4 Canada. fax: (416) 340-3314.
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Drouin-Chartier JP, Tremblay AJ, Lemelin V, Lamarche B, Couture P. Differential associations between plasma concentrations of insulin and glucose and intestinal expression of key genes involved in chylomicron metabolism. Am J Physiol Gastrointest Liver Physiol 2018; 315:G177-G184. [PMID: 29698057 DOI: 10.1152/ajpgi.00108.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The mechanisms underlying the oversecretion of apolipoprotein (apo)B-48-containing triglyceride-rich lipoproteins (TRL) in insulin-resistance (IR) states in humans remain to be fully understood. The objective of this study was to evaluate the association between the plasma levels of insulin and glucose and the intestinal expression of key genes involved in chylomicron metabolism in a large sample of nondiabetic men displaying various degrees of IR. Duodenal biopsies were obtained by gastroduodenoscopy in 127 men free of intestinal disease. Gene expression was measured using quantitative PCR in duodenal samples. Plasma insulin and glucose concentrations were measured in the fasting state. Postprandial TRL apoB-48 kinetics were measured using a primed-constant infusion of l-[5,5,5-D3]leucine for 12 h in a subgroup of 75 subjects maintained in a constant fed state. Plasma insulin levels were negatively associated with intestinal expression of ACS1 (standard β = -0.20, P = 0.007), DGAT1 (β = -0.18, P = 0.001), DGAT2 (β = -0.20, P = 0.02), and MTP (β = -0.27, P = 0.0005), whereas glucose levels were positively associated with MTP expression (β = 0.15, P = 0.04) independent of age, BMI, waist circumference, dietary intake, and duodenal expression of SREBP1c. Insulin levels, but not glucose concentrations, were positively correlated with postprandial TRL apoB-48 production rate ( r = 0.24, P = 0.04) and pool size ( r = 0.27, P = 0.03). In conclusion, plasma insulin and glucose levels are differentially associated with the expression of key genes involved in chylomicron metabolism. These results suggest that alterations in intestinal lipoprotein metabolism associated with IR may be regulated by plasma levels of both insulin and glucose concurrently and are therefore likely modified by the onset of insulin insufficiency. NEW & NOTEWORTHY We demonstrate that plasma insulin and glucose levels are differentially associated with the expression of key genes involved in chylomicron metabolism in men. For instance, intestinal expression of MTP is negatively associated with plasma insulin concentrations and positively associated with plasma glucose concentrations. Alterations in intestinal lipoprotein metabolism associated with insulin resistance may be regulated by plasma levels of both insulin and glucose concurrently and are therefore likely modified by the onset of insulin insufficiency.
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Affiliation(s)
| | - André J Tremblay
- Institute of Nutrition and Functional Foods, Laval University , Quebec City, Quebec , Canada
| | - Valéry Lemelin
- Department of Gastroenterology, Centre hospitalier universitaire de Québec-Laval University , Quebec City, Quebec , Canada
| | - Benoît Lamarche
- Institute of Nutrition and Functional Foods, Laval University , Quebec City, Quebec , Canada
| | - Patrick Couture
- Institute of Nutrition and Functional Foods, Laval University , Quebec City, Quebec , Canada.,Lipid Research Centre, Centre hospitalier universitaire de Québec-Laval University , Quebec City, Quebec , Canada
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11
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Drouin-Chartier JP, Tremblay AJ, Hogue JC, Lemelin V, Lamarche B, Couture P. Plasma PCSK9 correlates with apoB-48-containing triglyceride-rich lipoprotein production in men with insulin resistance. J Lipid Res 2018; 59:1501-1509. [PMID: 29946054 DOI: 10.1194/jlr.m086264] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 06/09/2018] [Indexed: 01/30/2023] Open
Abstract
Intestinal triglyceride (TG)-rich lipoproteins (TRLs) are important in the pathogenesis of atherosclerosis in insulin resistance (IR). We investigated the association of plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) concentrations with apoB-48-containing TRL metabolism in 148 men displaying various degrees of IR by measuring in vivo kinetics of TRL apoB-48 during a constant-fed state after a primed-constant infusion of L-[5,5,5-D3]leucine. Plasma PCSK9 concentrations positively correlated with TRL apoB-48 pool size (r = 0.31, P = 0.0002) and production rate (r = 0.24, P = 0.008) but not the fractional catabolic rate (r = -0.04, P = 0.6). Backward stepwise multiple linear regression analysis identified PCSK9 concentrations as a positive predictor of TRL apoB-48 production rate (standard β = +0.20, P = 0.007) independent of BMI, age, T2D/metformin use, dietary fat intake during the kinetic study, and fasting concentrations of TGs, insulin, glucose, LDL cholesterol, or C-reactive protein. We also assessed intestinal expression of key genes involved in chylomicron processing from duodenal samples of 71 men. Expression of PCSK9 and HMG-CoAR genes was positively associated (r = 0.43, P = 0.002). These results support PCSK9 association with intestinal secretion and plasma overaccumulation of TRL apoB-48 in men with IR.
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Affiliation(s)
| | - André J Tremblay
- Institute of Nutrition and Functional Foods Laval University, Quebec City, Canada
| | - Jean-Charles Hogue
- Centre Hospitalier Universitaire de Québec-Laval University, Quebec City, Canada
| | | | - Benoît Lamarche
- Institute of Nutrition and Functional Foods Laval University, Quebec City, Canada.,School of Nutrition, Laval University, Quebec City, Canada
| | - Patrick Couture
- Institute of Nutrition and Functional Foods Laval University, Quebec City, Canada .,Centre Hospitalier Universitaire de Québec-Laval University, Quebec City, Canada
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12
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Xiao C, Stahel P, Carreiro AL, Buhman KK, Lewis GF. Recent Advances in Triacylglycerol Mobilization by the Gut. Trends Endocrinol Metab 2018; 29:151-163. [PMID: 29306629 DOI: 10.1016/j.tem.2017.12.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 11/26/2022]
Abstract
Dietary lipid absorption and lipoprotein secretion by the gut are important in maintaining whole-body energy homeostasis and have significant implications for health and disease. The processing of dietary lipids, including storage within and subsequent mobilization and transport from enterocyte cytoplasmic lipid droplets or other intestinal lipid storage pools (including the secretary pathway, lamina propria and lymphatics) and secretion of chylomicrons, involves coordinated steps that are subject to various controls. This review summarizes recent advances in our understanding of the mechanisms that underlie lipid storage and mobilization by small intestinal enterocytes and the intestinal lymphatic vasculature. Therapeutic targeting of lipid processing by the gut may provide opportunities for the treatment and prevention of dyslipidemia, and for improving health status.
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Affiliation(s)
- Changting Xiao
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Priska Stahel
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Alicia L Carreiro
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Gary F Lewis
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada.
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13
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Drouin-Chartier JP, Tremblay AJ, Lépine MC, Lemelin V, Lamarche B, Couture P. Substitution of dietary ω-6 polyunsaturated fatty acids for saturated fatty acids decreases LDL apolipoprotein B-100 production rate in men with dyslipidemia associated with insulin resistance: a randomized controlled trial. Am J Clin Nutr 2018; 107:26-34. [PMID: 29381796 PMCID: PMC5972657 DOI: 10.1093/ajcn/nqx013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 10/24/2017] [Indexed: 12/11/2022] Open
Abstract
Background The substitution of omega (ω)-6 (n-6) polyunsaturated fatty acids (PUFAs) for saturated fatty acids (SFAs) is advocated in cardiovascular disease prevention. The impact of this substitution on lipoprotein metabolism in subjects with dyslipidemia associated with insulin resistance (IR) remains unknown. Objective In men with dyslipidemia and IR, we evaluated the impact of substituting ω-6 PUFAs for SFAs on the in vivo kinetics of apolipoprotein (apo) B-containing lipoproteins and on the intestinal expression of key genes involved in lipoprotein metabolism. Design Dyslipidemic and IR men (n = 36) were recruited for this double-blind, randomized, crossover, controlled trial. Subjects consumed, in a random order, a fully controlled diet rich in SFAs (SFAs: 13.4% of energy; ω-6 PUFAs: 4.0%) and a fully controlled diet rich in ω-6 PUFAs (SFAs: 6.0%; ω-6 PUFAs: 11.3%) for periods of 4 wk, separated by a 4-wk washout period. At the end of each diet, the in vivo kinetics of apoB-containing lipoproteins were measured and the intestinal expression of key genes involved in lipoprotein metabolism was quantified in duodenal biopsies taken from each participant. Results The substitution of ω-6 PUFAs for SFAs had no impact on TRL apoB-48 fractional catabolic rate (Δ = -3.8%, P = 0.7) and production rate (Δ = +1.2%, P = 0.9), although it downregulated the intestinal expression of the microsomal triglyceride transfer protein (Δ = -18.4%, P = 0.006) and apoB (Δ = -16.6%, P = 0.005). The substitution of ω-6 PUFAs for SFAs decreased the LDL apoB-100 pool size (Δ = -7.8%; P = 0.005). This difference was attributed to a reduction in the LDL apoB-100 production rate after the substitution of ω-6 PUFAs for SFAs (Δ = -10.0%; P = 0.003). Conclusions This study demonstrates that the substitution of dietary ω-6 PUFAs for SFAs decreases the production and number of LDL particles in men with dyslipidemia and IR. This trial was registered at clinicaltrials.gov as NCT01934543.
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Affiliation(s)
| | - André J Tremblay
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Quebec, Canada
| | - Marie-Claude Lépine
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Quebec, Canada
| | - Valéry Lemelin
- Department of Gastroenterology and Lipid Research Center, CHU de Québec-Université Laval, Quebec City, Quebec, Canada
| | - Benoît Lamarche
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Quebec, Canada
| | - Patrick Couture
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Quebec, Canada,Lipid Research Center, CHU de Québec-Université Laval, Quebec City, Quebec, Canada,Address correspondence to PC (e-mail: )
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14
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Sakamoto K, Kawamura M, Watanabe T, Ashidate K, Kohro T, Tanaka A, Mori Y, Tagami M, Hirano T, Yamazaki T, Shiba T. Effect of ezetimibe add-on therapy over 52 weeks extension analysis of prospective randomized trial (RESEARCH study) in type 2 diabetes subjects. Lipids Health Dis 2017; 16:122. [PMID: 28646901 PMCID: PMC5483302 DOI: 10.1186/s12944-017-0508-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 05/31/2017] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Lowering cholesterol levels decreases the risk of atherosclerotic diseases. Effective ways to stably reduce LDL-C level are warranted in type 2 diabetic patients, a high-risk population for CVD, with various anti-diabetic therapeutic background. The RESEARCH study focuses on LDL-C reduction in this population along with modifications of the lipid profiles. We evaluated long-term ezetimibe add-on therapy in T2DM patients with hypercholesterolemia. METHODS In a randomized, multicenter, open-label, prospective study, a total of 109 T2DM patients not attaining LDL-C target value despite first-line dose statin (10 mg of atorvastatin or 1 mg of pitavastatin) therapy in Japan were recruited. We investigated the difference in cholesterol lowering effect between ezetimibe (10 mg) add-on statin (EAT) group and double-dose statin (DST) group. Changes of parameters related to atherosclerotic event risks were assessed. RESULTS The reduction of LDL-C was larger in the EAT group (28.3%) than in the DST group (9.2%) at 52 weeks as well as the primary endpoint of 12 weeks. EAT achieved significant lower levels of TC and apo B, respectively. Both treatments attained significant reduction in sd-LDL-C or hsCRP on this long-term basis. Notably, sd-LDL-C in EAT reduced as low as 36.1 ± 14.9 mg/dl to reach near the threshold (35.0 mg/dl) for atherosclerosis with significantly higher achievement rate (55.6%) than DST treatment. Simultaneously, hsCRP reduction by EAT attained as low value as 0.52 ± 0.43 mg/l. CONCLUSIONS In the present 52-week long-term period, ezetimibe add-on therapy showed a robust advantage in lowering LDL-C and in attaining target LDL-C values compared with the doubling of statin dose. Moreover, it's meaningful that sd-LDL, powerfully atherogenic lipoprotein, exhibited prominent decrease consistently prominently by ezetimibe add-on therapy. DM patients with hypercholesterolemia are at high risk for CAD, and adding ezetimibe onto usual-dose statin treatment in Japan has been suggested as the first-line therapy for those DM patients who failed to attain the target LDL-C value (UMIN000002593).
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Affiliation(s)
- Kentaro Sakamoto
- Department of Diabetes and Metabolism, Toho University Ohashi Medical Center, 2-17-6, Ohashi, Meguro-ku, Tokyo, 1538515 Japan
| | - Mitsunobu Kawamura
- Division of Endocrinology and Metabolism Department of Internal Medicine, Tokyo Teishin Hospital, Tokyo, Japan
| | - Takayuki Watanabe
- Department of Internal Medicine, Yokohama City Minato Red Cross Hospital, Tokyo, Kanagawa Japan
| | - Keiko Ashidate
- Department of Internal Medicine, Kudanzaka Hospital, Tokyo, Japan
| | - Takahide Kohro
- Department of Medical Informatics / Cardiology, Jichi Medical University, Tochigi, Japan
| | - Akira Tanaka
- Nutrition Clinic, Kagawa Nutrition University, Tokyo, Japan
| | - Yasumichi Mori
- Department of Endocrinology and Metabolism, Toranomon Hospital, Tokyo, Japan
| | - Motoki Tagami
- Sanraku Hospital, Life-style related Disease Clinic, Tokyo, Japan
| | - Tsutomu Hirano
- Department of Medicine Division of Diabetes Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan
| | - Tsutomu Yamazaki
- Clinical Research Support Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Teruo Shiba
- Department of Diabetes and Metabolism, Toho University Ohashi Medical Center, 2-17-6, Ohashi, Meguro-ku, Tokyo, 1538515 Japan
- Division of Diabetes and Metabolism, Mitsui Memorial Hospital, Tokyo, Japan
| | - RESEARCH Study Group
- Department of Diabetes and Metabolism, Toho University Ohashi Medical Center, 2-17-6, Ohashi, Meguro-ku, Tokyo, 1538515 Japan
- Division of Endocrinology and Metabolism Department of Internal Medicine, Tokyo Teishin Hospital, Tokyo, Japan
- Department of Internal Medicine, Yokohama City Minato Red Cross Hospital, Tokyo, Kanagawa Japan
- Department of Internal Medicine, Kudanzaka Hospital, Tokyo, Japan
- Department of Medical Informatics / Cardiology, Jichi Medical University, Tochigi, Japan
- Nutrition Clinic, Kagawa Nutrition University, Tokyo, Japan
- Department of Endocrinology and Metabolism, Toranomon Hospital, Tokyo, Japan
- Sanraku Hospital, Life-style related Disease Clinic, Tokyo, Japan
- Department of Medicine Division of Diabetes Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan
- Clinical Research Support Center, The University of Tokyo Hospital, Tokyo, Japan
- Division of Diabetes and Metabolism, Mitsui Memorial Hospital, Tokyo, Japan
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Abstract
The metabolic syndrome is a cluster of risk factors (central obesity, hyperglycaemia, dyslipidaemia and arterial hypertension), indicating an increased risk of diabetes, cardiovascular disease and premature mortality. The gastrointestinal tract is seldom discussed as an organ system of principal importance for metabolic diseases. The present overview connects various metabolic research lines into an integrative physiological context in which the gastrointestinal tract is included. Strong evidence for the involvement of the gut in the metabolic syndrome derives from the powerful effects of weight-reducing (bariatric) gastrointestinal surgery. In fact, gastrointestinal surgery is now recommended as a standard treatment option for type 2 diabetes in obesity. Several gut-related mechanisms that potentially contribute to the metabolic syndrome will be presented. Obesity can be caused by hampered release of satiety-signalling gut hormones, reduced meal-associated energy expenditure and microbiota-assisted harvest of energy from nondigestible food ingredients. Adiposity per se is a well-established risk factor for hyperglycaemia. In addition, a leaky gut mucosa can trigger systemic inflammation mediating peripheral insulin resistance that together with a blunted incretin response aggravates the hyperglycaemic state. The intestinal microbiota is strongly associated with obesity and the related metabolic disease states, although the mechanisms involved remain unclear. Enterorenal signalling has been suggested to be involved in the pathophysiology of hypertension and postprandial triglyceride-rich chylomicrons; in addition, intestinal cholesterol metabolism probably contributes to atherosclerosis. It is likely that in the future, the metabolic syndrome will be treated according to novel pharmacological principles interfering with gastrointestinal functionality.
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Affiliation(s)
- L Fändriks
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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16
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Drouin-Chartier JP, Tremblay AJ, Hogue JC, Leclerc M, Labonté MÈ, Marin J, Lamarche B, Couture P. C-reactive protein levels are inversely correlated with the apolipoprotein B-48-containing triglyceride-rich lipoprotein production rate in insulin resistant men. Metabolism 2017; 68:163-172. [PMID: 28183448 DOI: 10.1016/j.metabol.2016.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Revised: 11/18/2016] [Accepted: 11/30/2016] [Indexed: 01/16/2023]
Abstract
UNLABELLED The pro-inflammatory state and elevated plasma levels of post-prandial triglycerides (TG) are associated with increased cardiovascular disease risk. Recent studies suggested that the increase in the production rate of post-prandial lipoproteins observed in patients with insulin resistance (IR) may be caused, at least in part, by the dysregulation of intestinal insulin sensitivity triggered by inflammation. OBJECTIVE The objective of the present study was to evaluate the association between IR, plasma C-reactive protein (CRP) levels and the kinetics of TG-rich lipoprotein (TRL) containing apolipoprotein (apo) B-48 in a large sample of insulin sensitive (IS) and IR men. METHODS The in vivo kinetics of TRL apoB-48 were measured in 151 men following a primed-constant infusion of l-[5,5,5-D3]leucine. IR subjects (n=91) were characterized by fasting TG levels ≥1.5mmol/L and an index of homeostasis model assessment of IR (HOMA-IR)≥2.5 or type 2 diabetes, while IS subjects (n=24) were characterized by an HOMA-IR index <2.5 and TG levels <1.5mmol/L. RESULTS IR subjects had higher TRL apoB-48 production rate (+202%; P<0.0001) and CRP levels (+51%; P=0.01) than IS subjects. TRL apoB-48 production rate and CRP levels were inversely correlated in IR subjects (r=-0.32; P=0.002). IR subjects with CRP levels above the median (2.20mg/L) had lower TRL apoB-48 production rate than IR subjects with CRP levels below the median (Δ=-24%; P<0.05). CONCLUSION Our results confirm that IR is associated with increased TRL apoB-48 secretion and suggest that a higher inflammatory status is associated with decreased TRL apoB-48 secretion among IR subjects.
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Affiliation(s)
| | - André J Tremblay
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
| | | | - Myriam Leclerc
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
| | - Marie-Ève Labonté
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
| | - Johanne Marin
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
| | - Benoît Lamarche
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
| | - Patrick Couture
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada; CHUQ Research Center, Laval University, Quebec City, Canada.
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17
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Drouin-Chartier JP, Tremblay AJ, Lemelin V, Lépine MC, Lamarche B, Couture P. Ezetimibe increases intestinal expression of the LDL receptor gene in dyslipidaemic men with insulin resistance. Diabetes Obes Metab 2016; 18:1226-1235. [PMID: 27460541 DOI: 10.1111/dom.12749] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/11/2016] [Accepted: 07/21/2016] [Indexed: 01/25/2023]
Abstract
AIM To gain further insight into intestinal cholesterol homeostasis in dyslipidaemic men with insulin resistance (IR) by examining the impact of treatment with ezetimibe on the expression of key genes involved in cholesterol synthesis and LDL receptor (R)-mediated uptake of lipoproteins. METHODS A total of 25 men with dyslipidaemia and IR were recruited to participate in this double-blind, randomized, crossover, placebo-controlled trial. Participants received 10 mg/day ezetimibe or placebo for periods of 12 weeks each. Intestinal gene expression was measured by quantitative PCR in duodenal biopsy samples collected by gastroduodenoscopy at the end of each treatment. RESULTS A total of 20 participants completed the protocol. Treatment with ezetimibe significantly increased intestinal LDLR (+16.2%; P = .01), 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoAR; +14.0%; P = .04) and acetyl-Coenzyme A acetyltransferase 2 (ACAT-2) mRNA expression (+12.5%; P = .03). Changes in sterol regulatory element-binding transcription factor 2 (SREBP-2) expression were significantly correlated with changes in HMG-CoAR (r = 0.55; P < .05), ACAT-2 (r = 0.69; P < .001) and proprotein convertase substilisin/kexin type 9 (PCSK9) expression (r = 0.45; P < .05). CONCLUSIONS These results show that inhibition of intestinal cholesterol absorption by ezetimibe increases expression of the LDLR gene, supporting the concept that increased LDL clearance with ezetimibe treatment occurs not only in the liver but also in the small intestine.
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Affiliation(s)
| | - André J Tremblay
- Department of Medicine, Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
| | - Valéry Lemelin
- Department of Gastroenterology, CHU de Québec-Université Laval, Quebec City, Canada
| | - Marie-Claude Lépine
- Department of Medicine, Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
| | - Benoît Lamarche
- Department of Medicine, Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
| | - Patrick Couture
- Department of Medicine, Institute of Nutrition and Functional Foods, Laval University, Quebec City, Canada
- Department of Medicine, Lipid Research Center, CHU de Québec-Université Laval, Quebec City, Canada
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18
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Buttet M, Poirier H, Traynard V, Gaire K, Tran TTT, Sundaresan S, Besnard P, Abumrad NA, Niot I. Deregulated Lipid Sensing by Intestinal CD36 in Diet-Induced Hyperinsulinemic Obese Mouse Model. PLoS One 2016; 11:e0145626. [PMID: 26727015 PMCID: PMC4703141 DOI: 10.1371/journal.pone.0145626] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/07/2015] [Indexed: 12/28/2022] Open
Abstract
The metabolic syndrome (MetS) greatly increases risk of cardiovascular disease and diabetes and is generally associated with abnormally elevated postprandial triglyceride levels. We evaluated intestinal synthesis of triglyceride-rich lipoproteins (TRL) in a mouse model of the MetS obtained by feeding a palm oil-rich high fat diet (HFD). By contrast to control mice, MetS mice secreted two populations of TRL. If the smaller size population represented 44% of total particles in the beginning of intestinal lipid absorption in MetS mice, it accounted for only 17% after 4 h due to the secretion of larger size TRL. The MetS mice displayed accentuated postprandial hypertriglyceridemia up to 3 h due to a defective TRL clearance. These alterations reflected a delay in lipid induction of genes for key proteins of TRL formation (MTP, L-FABP) and blood clearance (ApoC2). These abnormalities associated with blunted lipid sensing by CD36, which is normally required to optimize jejunal formation of large TRL. In MetS mice CD36 was not downregulated by lipid in contrast to control mice. Treatment of controls with the proteosomal inhibitor MG132, which prevented CD36 downregulation, resulted in blunted lipid-induction of MTP, L-FABP and ApoC2 gene expression, as in MetS mice. Absence of CD36 sensing was due to the hyperinsulinemia in MetS mice. Acute insulin treatment of controls before lipid administration abolished CD36 downregulation, lipid-induction of TRL genes and reduced postprandial triglycerides (TG), while streptozotocin-treatment of MetS mice restored lipid-induced CD36 degradation and TG secretion. In vitro, insulin treatment abolished CD36-mediated up-regulation of MTP in Caco-2 cells. In conclusion, HFD treatment impairs TRL formation in early stage of lipid absorption via insulin-mediated inhibition of CD36 lipid sensing. This impairment results in production of smaller TRL that are cleared slowly from the circulation, which might contribute to the reported association of CD36 variants with MetS risk.
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Affiliation(s)
- Marjorie Buttet
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Hélène Poirier
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Véronique Traynard
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Kévin Gaire
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Thi Thu Trang Tran
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Sinju Sundaresan
- Department of Medicine, Gastroenterology Division, University of Michigan, Ann Arbor, Michigan, 48109, United States of America
| | - Philippe Besnard
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Nada A. Abumrad
- Department of Medicine, Center for Human Nutrition, and Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, Missouri, 63110, United States of America
| | - Isabelle Niot
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
- * E-mail:
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19
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Veilleux A, Mayeur S, Bérubé JC, Beaulieu JF, Tremblay E, Hould FS, Bossé Y, Richard D, Levy E. Altered intestinal functions and increased local inflammation in insulin-resistant obese subjects: a gene-expression profile analysis. BMC Gastroenterol 2015; 15:119. [PMID: 26376914 PMCID: PMC4574092 DOI: 10.1186/s12876-015-0342-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 08/25/2015] [Indexed: 03/15/2023] Open
Abstract
BACKGROUND Metabolic alterations relevant to postprandial dyslipidemia were previously identified in the intestine of obese insulin-resistant subjects. The aim of the study was to identify the genes deregulated by systemic insulin resistance in the intestine of severely obese subjects. METHODS Transcripts from duodenal samples of insulin-sensitive (HOMA-IR < 3, n = 9) and insulin-resistant (HOMA-IR > 7, n = 9) obese subjects were assayed by microarray (Illumina HumanHT-12). RESULTS A total of 195 annotated genes were identified as differentially expressed between these two groups (Fold change > 1.2). Of these genes, 36 were found to be directly involved in known intestinal functions, including digestion, extracellular matrix, endocrine system, immunity and cholesterol metabolism. Interestingly, all differentially expressed genes (n = 8) implicated in inflammation and oxidative stress were found to be upregulated in the intestine of insulin-resistant compared to insulin-sensitive subjects. Metabolic pathway analysis revealed that several signaling pathways involved in immunity and inflammation were significantly enriched in differently expressed genes and were predicted to be activated in the intestine of insulin-resistant subjects. Using stringent criteria (Fold change > 1.5; FDR < 0.05), three genes were found to be significantly and differently expressed in the intestine of insulin-resistant compared to insulin-sensitive subjects: the transcripts of the insulinotropic glucose-dependant peptide (GIP) and of the β-microseminoprotein (MSMB) were significantly reduced, but that of the humanin like-1 (MTRNR2L1) was significantly increased. CONCLUSION These results underline that systemic insulin resistance is associated with remodeling of key intestinal functions. Moreover, these data indicate that small intestine metabolic dysfunction is accompanied with a local amplification of low-grade inflammatory process implicating several pathways. Genes identified in this study are potentially triggered throughout the development of intestinal metabolic abnormalities, which could contribute to dyslipidemia, a component of metabolic syndrome and diabetes.
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Affiliation(s)
- Alain Veilleux
- Department of Nutrition, Université de Montréal and Research center of CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, Qc, Canada.
| | - Sylvain Mayeur
- Department of Nutrition, Université de Montréal and Research center of CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, Qc, Canada.
| | - Jean-Christophe Bérubé
- Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Université Laval, Québec, Qc, Canada.
| | - Jean-François Beaulieu
- Departement of Anatomy and cellular biology, Université de Sherbrooke, Sherbrooke, Qc, Canada. .,Canada Research Chair in Intestinal Physiopathology, Sherbrooke, Québec, Canada.
| | - Eric Tremblay
- Departement of Anatomy and cellular biology, Université de Sherbrooke, Sherbrooke, Qc, Canada.
| | - Frédéric-Simon Hould
- Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Université Laval, Québec, Qc, Canada. .,Departement of surgery, Université Laval, Québec, Qc, Canada.
| | - Yohan Bossé
- Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Université Laval, Québec, Qc, Canada. .,Department of Molecular Medicine, Université Laval, Quebec, Qc, Canada.
| | - Denis Richard
- Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Université Laval, Québec, Qc, Canada. .,Department of Molecular Medicine, Université Laval, Quebec, Qc, Canada. .,Chaire de Recherche Merck Frosst/IRSC Research Chair on Obesity, Québec, Qc, Canada.
| | - Emile Levy
- Department of Nutrition, Université de Montréal and Research center of CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, Qc, Canada. .,JA. deSève Research Chair in nutrition, Montréal, Qc, Canada.
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20
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Bourassa S, Fournier F, Nehmé B, Kelly I, Tremblay A, Lemelin V, Lamarche B, Couture P, Droit A. Evaluation of iTRAQ and SWATH-MS for the Quantification of Proteins Associated with Insulin Resistance in Human Duodenal Biopsy Samples. PLoS One 2015; 10:e0125934. [PMID: 25950531 PMCID: PMC4423961 DOI: 10.1371/journal.pone.0125934] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/19/2015] [Indexed: 01/08/2023] Open
Abstract
Insulin resistance (IR) is associated with increased production of triglyceride-rich lipoproteins of intestinal origin. In order to assess whether insulin resistance affects the proteins involved in lipid metabolism, we used two mass spectrometry based quantitative proteomics techniques to compare the intestinal proteome of 14 IR patients to that of 15 insulin sensitive (IS) control patients matched for age and waist circumference. A total of 3886 proteins were identified by the iTRAQ (Isobaric Tags for Relative and Absolute Quantitation) mass spectrometry approach and 2290 by the SWATH-MS strategy (Serial Window Acquisition of Theoretical Spectra). Using these two methods, 208 common proteins were identified with a confidence corresponding to FDR < 1%, and quantified with p-value < 0.05. The quantification of those 208 proteins has a Pearson correlation coefficient (r2) of 0.728 across the two techniques. Gene Ontology analyses of the differentially expressed proteins revealed that annotations related to lipid metabolic process and oxidation reduction process are overly represented in the set of under-expressed proteins in IR subjects. Furthermore, both methods quantified proteins of relevance to IR. These data also showed that SWATH-MS is a promising and compelling alternative to iTRAQ for protein quantitation of complex mixtures.
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Affiliation(s)
- Sylvie Bourassa
- Proteomics Center, CHU de Québec Research Center and Department of Molecular Medicine, Laval University, Quebec, Canada
| | - Frédéric Fournier
- Proteomics Center, CHU de Québec Research Center and Department of Molecular Medicine, Laval University, Quebec, Canada
| | - Benjamin Nehmé
- Proteomics Center, CHU de Québec Research Center and Department of Molecular Medicine, Laval University, Quebec, Canada
| | - Isabelle Kelly
- Proteomics Center, CHU de Québec Research Center and Department of Molecular Medicine, Laval University, Quebec, Canada
| | - André Tremblay
- Lipid Research Center, Centre Hospitalier de l’Université Laval Research Center, Laval University, Quebec, Canada
| | - Valéry Lemelin
- Lipid Research Center, Centre Hospitalier de l’Université Laval Research Center, Laval University, Quebec, Canada
| | - Benoit Lamarche
- Lipid Research Center, Centre Hospitalier de l’Université Laval Research Center, Laval University, Quebec, Canada
| | - Patrick Couture
- Lipid Research Center, Centre Hospitalier de l’Université Laval Research Center, Laval University, Quebec, Canada
| | - Arnaud Droit
- Proteomics Center, CHU de Québec Research Center and Department of Molecular Medicine, Laval University, Quebec, Canada
- * E-mail:
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Tremblay AJ, Lamarche B, Kelly I, Charest A, Lépine MC, Droit A, Couture P. Effect of sitagliptin therapy on triglyceride-rich lipoprotein kinetics in patients with type 2 diabetes. Diabetes Obes Metab 2014; 16:1223-9. [PMID: 25059982 DOI: 10.1111/dom.12359] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/17/2014] [Accepted: 07/21/2014] [Indexed: 02/06/2023]
Abstract
AIM To investigate the effects of sitagliptin therapy on the kinetics of triglyceride-rich lipoprotein (TRL) apolipoprotein (apo)B-48, VLDL apoB-100, apoE and apoC-III in patients with type 2 diabetes. METHODS Twenty-two subjects with type 2 diabetes were recruited in this double-blind crossover study, during which the subjects received sitagliptin (100 mg/day) or placebo for a 6-week period each. At the end of each phase of treatment, the in vivo kinetics of the different apolipoproteins were assessed using a primed-constant infusion of l-[5,5,5-D3]leucine for 12 h, with the participants in a constantly fed state. RESULTS Sitagliptin therapy significantly reduced fasting plasma triglyceride (-15.4%, p = 0.03), apoB-48 (-16.3%, p = 0.03) and free fatty acid concentrations (-9.5%, p = 0.04), as well as plasma HbA1c (placebo: 7.0% ± 0.8 vs. sitagliptin: 6.6% ± 0.7, p < 0.0001) and plasma glucose levels (-13.5%, p = 0.001), without any significant effect on insulin levels. Kinetic results showed that treatment with sitagliptin significantly reduced the pool size of TRL apoB-48 by -20.8% (p = 0.03), paralleled by a reduction in the production rate of these particles (-16.0%, p = 0.03). The VLDL apoB-100 pool size was also significantly decreased by sitagliptin therapy (-9.3%, p = 0.03), mainly because of a reduction in the hepatic secretion of these lipoproteins, although this difference did not reach statistical significance (-9.2%, p = 0.06). CONCLUSIONS Treatment with sitagliptin for 6 weeks reduced triglyceride-rich apoB-containing lipoprotein levels by reducing the synthesis of these particles.
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Affiliation(s)
- A J Tremblay
- Lipid Research Centre, Centre Hospitalier de l'Université Laval (CHUL) Research Centre, Quebec City, QC, Canada; Institute of Nutrition and Functional Foods, Laval University, Quebec City, QC, Canada
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Abstract
PURPOSE OF REVIEW To summarize the evidence for the presence of two lipid absorption pathways and their regulation. RECENT FINDINGS Lipid absorption involves hydrolysis of dietary fat in the lumen of the intestine, followed by the uptake of hydrolyzed products by enterocytes. Lipids are resynthesized in the endoplasmic reticulum and are either secreted with chylomicrons and HDLs or stored as cytoplasmic lipid droplets. Lipids in the droplets are hydrolyzed and are secreted at a later time. Secretion of lipids by the chylomicron and HDL pathways are dependent on microsomal triglyceride transfer protein (MTP) and ATP-binding cassette family A protein 1, respectively, and are regulated independently. Gene-ablation studies showed that MTP function and chylomicron assembly is essential for the absorption of triglycerides. Ablation of MTP abolishes triglyceride absorption and results in massive triglyceride accumulation in enterocytes. Although the majority of phospholipid, cholesterol, and vitamin E are absorbed through the chylomicron pathway, a significant amount of these lipids are also absorbed via the HDL pathway. Chylomicron assembly and secretion is increased by the enhanced availability of fatty acids, whereas the HDL pathway is upregulated by liver X receptor agonists. SUMMARY Triglycerides are exclusively transported with chylomicrons and this process is critically dependent on MTP. In addition to chylomicrons, absorption of phospholipids, free cholesterol, retinol, and vitamin E also involves HDLs. These two pathways are complementary and are regulated independently. They may be targeted to lower lipid absorption in order to control hyperlipidemia, obesity, metabolic syndrome, steatosis, insulin resistance, atherosclerosis, and other disorders.
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Affiliation(s)
- M Mahmood Hussain
- aDepartment of Cell Biology bDepartment of Pediatrics, SUNY Downstate Medical Center cVA New York Harbor Healthcare System, Brooklyn, New York, USA
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Beyond the Standard Lipid Profile: What is Known about Apolipoproteins, Lp(a), and Lipoprotein Particle Distributions in Children. CURRENT CARDIOVASCULAR RISK REPORTS 2014. [DOI: 10.1007/s12170-014-0381-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Veilleux A, Grenier É, Marceau P, Carpentier AC, Richard D, Levy E. Intestinal Lipid Handling. Arterioscler Thromb Vasc Biol 2014; 34:644-53. [DOI: 10.1161/atvbaha.113.302993] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Alain Veilleux
- From the Department of Nutrition, Université de Montréal, Research Center, CHU Sainte-Justine, Montréal, Québec, Canada (A.V., É.G., E.L.); Department of Surgery, Université Laval, Québec, Canada (P.M.); Department of Medicine, Université de Sherbrooke, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada (A.C.C.); Centre de Recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada (D.R.); and Laboratoire de Lipidologie, Métabolisme et Nutrition,
| | - Émilie Grenier
- From the Department of Nutrition, Université de Montréal, Research Center, CHU Sainte-Justine, Montréal, Québec, Canada (A.V., É.G., E.L.); Department of Surgery, Université Laval, Québec, Canada (P.M.); Department of Medicine, Université de Sherbrooke, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada (A.C.C.); Centre de Recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada (D.R.); and Laboratoire de Lipidologie, Métabolisme et Nutrition,
| | - Picard Marceau
- From the Department of Nutrition, Université de Montréal, Research Center, CHU Sainte-Justine, Montréal, Québec, Canada (A.V., É.G., E.L.); Department of Surgery, Université Laval, Québec, Canada (P.M.); Department of Medicine, Université de Sherbrooke, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada (A.C.C.); Centre de Recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada (D.R.); and Laboratoire de Lipidologie, Métabolisme et Nutrition,
| | - André C. Carpentier
- From the Department of Nutrition, Université de Montréal, Research Center, CHU Sainte-Justine, Montréal, Québec, Canada (A.V., É.G., E.L.); Department of Surgery, Université Laval, Québec, Canada (P.M.); Department of Medicine, Université de Sherbrooke, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada (A.C.C.); Centre de Recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada (D.R.); and Laboratoire de Lipidologie, Métabolisme et Nutrition,
| | - Denis Richard
- From the Department of Nutrition, Université de Montréal, Research Center, CHU Sainte-Justine, Montréal, Québec, Canada (A.V., É.G., E.L.); Department of Surgery, Université Laval, Québec, Canada (P.M.); Department of Medicine, Université de Sherbrooke, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada (A.C.C.); Centre de Recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada (D.R.); and Laboratoire de Lipidologie, Métabolisme et Nutrition,
| | - Emile Levy
- From the Department of Nutrition, Université de Montréal, Research Center, CHU Sainte-Justine, Montréal, Québec, Canada (A.V., É.G., E.L.); Department of Surgery, Université Laval, Québec, Canada (P.M.); Department of Medicine, Université de Sherbrooke, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada (A.C.C.); Centre de Recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada (D.R.); and Laboratoire de Lipidologie, Métabolisme et Nutrition,
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