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Bruls YMH, op den Kamp YJM, Phielix E, Lindeboom L, Havekes B, Schaart G, Moonen-Kornips E, Wildberger JE, Hesselink MKC, Schrauwen P, Schrauwen-Hinderling VB. L-carnitine infusion does not alleviate lipid-induced insulin resistance and metabolic inflexibility. PLoS One 2020; 15:e0239506. [PMID: 32976523 PMCID: PMC7518598 DOI: 10.1371/journal.pone.0239506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 09/07/2020] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Low carnitine status may underlie the development of insulin resistance and metabolic inflexibility. Intravenous lipid infusion elevates plasma free fatty acid (FFA) concentration and is a model for simulating insulin resistance and metabolic inflexibility in healthy, insulin sensitive volunteers. Here, we hypothesized that co-infusion of L-carnitine may alleviate lipid-induced insulin resistance and metabolic inflexibility. METHODS In a randomized crossover trial, eight young healthy volunteers underwent hyperinsulinemic-euglycemic clamps (40mU/m2/min) with simultaneous infusion of saline (CON), Intralipid (20%, 90mL/h) (LIPID), or Intralipid (20%, 90mL/h) combined with L-carnitine infusion (28mg/kg) (LIPID+CAR). Ten volunteers were randomized for the intervention arms (CON, LIPID and LIPID+CAR), but two dropped-out during the study. Therefore, eight volunteers participated in all three intervention arms and were included for analysis. RESULTS L-carnitine infusion elevated plasma free carnitine availability and resulted in a more pronounced increase in plasma acetylcarnitine, short-, medium-, and long-chain acylcarnitines compared to lipid infusion, however no differences in skeletal muscle free carnitine or acetylcarnitine were found. Peripheral insulin sensitivity and metabolic flexibility were blunted upon lipid infusion compared to CON but L-carnitine infusion did not alleviate this. CONCLUSION Acute L-carnitine infusion could not alleviated lipid-induced insulin resistance and metabolic inflexibility and did not alter skeletal muscle carnitine availability. Possibly, lipid-induced insulin resistance may also have affected carnitine uptake and may have blunted the insulin-induced carnitine storage in muscle. Future studies are needed to investigate this.
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Affiliation(s)
- Yvonne M. H. Bruls
- Departments of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
- Departments of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Yvo J. M. op den Kamp
- Departments of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Esther Phielix
- Departments of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Lucas Lindeboom
- Departments of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
- Departments of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Bas Havekes
- Division of Endocrinology, Department of Internal Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Gert Schaart
- Departments of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Esther Moonen-Kornips
- Departments of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Joachim E. Wildberger
- Departments of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Matthijs K. C. Hesselink
- Departments of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Patrick Schrauwen
- Departments of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Vera B. Schrauwen-Hinderling
- Departments of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
- Departments of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands
- * E-mail:
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Bruls YM, de Ligt M, Lindeboom L, Phielix E, Havekes B, Schaart G, Kornips E, Wildberger JE, Hesselink MK, Muoio D, Schrauwen P, Schrauwen-Hinderling VB. Carnitine supplementation improves metabolic flexibility and skeletal muscle acetylcarnitine formation in volunteers with impaired glucose tolerance: A randomised controlled trial. EBioMedicine 2019; 49:318-330. [PMID: 31676389 PMCID: PMC6945245 DOI: 10.1016/j.ebiom.2019.10.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/10/2019] [Accepted: 10/10/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Type 2 diabetes patients and individuals at risk of developing diabetes are characterized by metabolic inflexibility and disturbed glucose homeostasis. Low carnitine availability may contribute to metabolic inflexibility and impaired glucose tolerance. Here, we investigated whether carnitine supplementation improves metabolic flexibility and insulin sensitivity in impaired glucose tolerant (IGT) volunteers. METHODS Eleven IGT- volunteers followed a 36-day placebo- and L-carnitine treatment (2 g/day) in a randomised, placebo-controlled, double blind crossover design. A hyperinsulinemic-euglycemic clamp (40 mU/m2/min), combined with indirect calorimetry (ventilated hood) was performed to determine insulin sensitivity and metabolic flexibility. Furthermore, metabolic flexibility was assessed in response to a high-energy meal. Skeletal muscle acetylcarnitine concentrations were measured in vivo using long echo time proton magnetic resonance spectroscopy (1H-MRS, TE=500 ms) in the resting state (7:00AM and 5:00PM) and after a 30-min cycling exercise. Twelve normal glucose tolerant (NGT) volunteers were included without any intervention as control group. RESULTS Metabolic flexibility of IGT-subjects completely restored towards NGT control values upon carnitine supplementation, measured during a hyperinsulinemic-euglycemic clamp and meal test. In muscle, carnitine supplementation enhanced the increase in resting acetylcarnitine concentrations over the day (delta 7:00 AM versus 5:00 PM) in IGT-subjects. Furthermore, carnitine supplementation increased post-exercise acetylcarnitine concentrations and reduced long-chain acylcarnitine species in IGT-subjects, suggesting the stimulation of a more complete fat oxidation in muscle. Whole-body insulin sensitivity was not affected. CONCLUSION Carnitine supplementation improves acetylcarnitine formation and rescues metabolic flexibility in IGT-subjects. Future research should investigate the potential of carnitine in prevention/treatment of type 2 diabetes.
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Affiliation(s)
- Yvonne Mh Bruls
- Department of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands; Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Marlies de Ligt
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Lucas Lindeboom
- Department of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands; Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Esther Phielix
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Bas Havekes
- Department of Internal Medicine, Division of Endocrinology, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Gert Schaart
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Esther Kornips
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Joachim E Wildberger
- Department of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Matthijs Kc Hesselink
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Deborah Muoio
- Department of Medicine, Duke University Medical Center, Durham, NC NC22704, United States of America
| | - Patrick Schrauwen
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands
| | - Vera B Schrauwen-Hinderling
- Department of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands; Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200 MD Maastricht, the Netherlands.
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Dang J, Yang M, Zhang X, Ruan H, Qin G, Fu J, Shen Z, Tan A, Li R, Moore J. Associations of Exposure to Air Pollution with Insulin Resistance: A Systematic Review and Meta-Analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:E2593. [PMID: 30463387 PMCID: PMC6266153 DOI: 10.3390/ijerph15112593] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/16/2018] [Accepted: 11/16/2018] [Indexed: 12/20/2022]
Abstract
In this article, we review the available evidence and explore the association between air pollution and insulin resistance (IR) using meta-analytic techniques. Cohort studies published before January 2018 were selected through English-language literature searches in nine databases. Six cohort studies were included in our sample, which assessed air pollutants including PM2.5 (particulate matter with an aerodynamic diameter less than or equal to 2.5 μm), NO₂(nitrogen dioxide), and PM10 (particulate matter with an aerodynamic diameter less than 10 μm). Percentage change in insulin or insulin resistance associated with air pollutants with corresponding 95% confidence interval (CI) was used to evaluate the risk. A pooled effect (percentage change) was observed, with a 1 μg/m³ increase in NO₂ associated with a significant 1.25% change (95% CI: 0.67, 1.84; I² = 0.00%, p = 0.07) in the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and a 0.60% change (95% CI: 0.17, 1.03; I² = 30.94%, p = 0.27) in insulin. Similar to the analysis of NO₂, a 1 μg/m³ increase in PM10 was associated with a significant 2.77% change (95% CI: 0.67, 4.87; I² = 94.98%, p < 0.0001) in HOMA-IR and a 2.75% change in insulin (95% CI: 0.45, 5.04; I² = 58.66%, p = 0.057). No significant associations were found between PM2.5 and insulin resistance biomarkers. We conclude that increased exposure to air pollution can lead to insulin resistance, further leading to diabetes and cardiometabolic diseases. Clinicians should consider the environmental exposure of patients when making screening and treatment decisions for them.
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Affiliation(s)
- Jiajia Dang
- School of Health Sciences, Wuhan University, 115 Donghu Road, Wuhan 430071, China.
| | - Mengtong Yang
- School of Health Sciences, Wuhan University, 115 Donghu Road, Wuhan 430071, China.
| | - Xinge Zhang
- School of Health Sciences, Wuhan University, 115 Donghu Road, Wuhan 430071, China.
| | - Haotian Ruan
- School of Health Sciences, Wuhan University, 115 Donghu Road, Wuhan 430071, China.
| | - Guiyu Qin
- School of Health Sciences, Wuhan University, 115 Donghu Road, Wuhan 430071, China.
| | - Jialin Fu
- School of Health Sciences, Wuhan University, 115 Donghu Road, Wuhan 430071, China.
| | - Ziqiong Shen
- School of Health Sciences, Wuhan University, 115 Donghu Road, Wuhan 430071, China.
| | - Anran Tan
- School of Health Sciences, Wuhan University, 115 Donghu Road, Wuhan 430071, China.
| | - Rui Li
- School of Health Sciences, Wuhan University, 115 Donghu Road, Wuhan 430071, China.
| | - Justin Moore
- Department of Family & Community Medicine, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
- Department of Epidemiology & Prevention, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
- Department of Implementation Science, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
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Methods for quantifying adipose tissue insulin resistance in overweight/obese humans. Int J Obes (Lond) 2017; 41:1288-1294. [PMID: 28465607 DOI: 10.1038/ijo.2017.110] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/16/2017] [Accepted: 04/19/2017] [Indexed: 12/21/2022]
Abstract
BACKGROUND/OBJECTIVES Insulin resistance of adipose tissue is an important feature of obesity-related metabolic disease. However, assessment of lipolysis in humans requires labor-intensive and expensive methods, and there is limited validation of simplified measurement methods. We aimed to validate simplified methods for the quantification of adipose tissue insulin resistance against the assessment of insulin sensitivity of lipolysis suppression during hyperinsulinemic-euglycemic clamp studies. SUBJECTS/METHODS We assessed the insulin-mediated suppression of lipolysis by tracer-dilution of [1,1,2,3,3-2H5]glycerol during hyperinsulinemic-euglycemic clamp studies in 125 overweight or obese adults (85 men, 40 women; age 50±11 years; body mass index 38±7 kg m-2). Seven indices of adipose tissue insulin resistance were validated against the reference measurement method. RESULTS Low-dose insulin infusion resulted in suppression of the glycerol rate of appearance ranging from 4% (most resistant) to 85% (most sensitive), indicating a good range of adipose tissue insulin sensitivity in the study population. The reference method correlated with (1) insulin-mediated suppression of plasma glycerol concentrations (r=0.960, P<0.001), (2) suppression of plasma non-esterified fatty acid (NEFA) concentrations (r=0.899, P<0.001), (3) the Adipose tissue Insulin Resistance (Adipo-IR) index (fasting plasma insulin-NEFA product; r=-0.526, P<0.001), (4) the fasting plasma insulin-glycerol product (r=-0.467, P<0.001), (5) the Adipose Tissue Insulin Resistance Index (fasting plasma insulin-basal lipolysis product; r=0.460, P<0.001), (6) the Quantitative Insulin Sensitivity Check Index (QUICKI)-NEFA index (r=0.621, P<0.001), and (7) the QUICKI-glycerol index (r=0.671, P<0.001). Bland-Altman plots showed no systematic errors for the suppression indices but proportional errors for all fasting indices. Receiver-operator characteristic curves confirmed that all indices were able to detect adipose tissue insulin resistance (area under the curve ⩾0.801, P<0.001). CONCLUSIONS Adipose tissue insulin sensitivity (that is, the antilipolytic action of insulin) can be reliably quantified in overweight and obese humans by simplified index methods. The sensitivity and specificity of the Adipo-IR index and the fasting plasma insulin-glycerol product, combined with their simplicity and acceptable agreement, suggest that these may be most useful in clinical practice.
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Choi YH, Kim JH, Lee BE, Hong YC. Urinary benzene metabolite and insulin resistance in elderly adults. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 482-483:260-8. [PMID: 24657371 DOI: 10.1016/j.scitotenv.2014.02.121] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 02/26/2014] [Accepted: 02/26/2014] [Indexed: 05/11/2023]
Abstract
BACKGROUND Benzene is a volatile organic compound present in traffic-related and indoor air pollution. It is of particular concern since it is known to induce oxidative stress, which can affect insulin resistance (IR). We therefore examined the association between exposure to environmental benzene and IR in the elderly. STUDY DESIGN Between 2008 and 2010, benzene metabolite levels (urinary trans,trans-muconic acid (t,t-MA)) and homeostatic model assessment index (HOMA-IR) were repeatedly measured in 505 adults aged ≥60 years. Linear mixed-effect models and marginal logistic models were used to evaluate associations of t,t-MA concentration with HOMA-IR score and elevated IR, defined as HOMA-IR ≥2.6. RESULTS After adjustment for sociodemographic and behavioral factors, environmental co-exposures, and metabolic conditions, quartile levels of urinary t,t-MA demonstrated a dose-dependent association with elevated IR (p-trend<0.001) and the level of oxidative stress estimated by urinary malondialdehyde (p-trend<0.001). As compared to the lowest quartile, the upper quartiles of t,t-MA (t,t-MA concentration >0.017mg/g CR) were associated with elevated IR [odds ratio=Q2: 2.00 (95% confidence interval (CI): 1.16-3.46); Q3: 3.33 (95% CI: 1.90-5.84); Q4: 2.07 (95% CI: 1.02-4.22)]. CONCLUSION Urinary benzene at levels currently observed in the urban elderly population is associated with IR, independent of traditional risk factors. Reduction of community-level exposure to benzene is therefore important for the effective prevention of IR in older adults.
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Affiliation(s)
- Yoon-Hyeong Choi
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Institute of Environmental Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Jin Hee Kim
- Institute of Environmental Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Environmental Health Center, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Bo-Eun Lee
- Environmental Health Research Division, National Institute of Environmental Research, Incheon, Republic of Korea
| | - Yun-Chul Hong
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Institute of Environmental Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Environmental Health Center, Seoul National University Medical Research Center, Seoul, Republic of Korea.
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Nassis GP, Sidossis LS. Methods for assessing body composition, cardiovascular and metabolic function in children and adolescents: implications for exercise studies. Curr Opin Clin Nutr Metab Care 2006; 9:560-7. [PMID: 16912551 DOI: 10.1097/01.mco.0000241665.38385.5b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW To critically evaluate the most recent literature on the methods used to assess body composition, cardiovascular and metabolic function in children and adolescents. RECENT FINDINGS Although regional body composition can be fairly accurately calculated by dual-energy X-ray absorptiometry, the accuracy of noninvasive estimations of visceral adipose tissue is questionable. Regarding the cardiovascular and metabolic adaptations, there is no doubt that direct and invasive methods provide high accuracy and reproducibility. For instance, exercise until exhaustion, direct Fick equation, nuclear magnetic resonance and magnetic resonance imaging are valid methods to determine maximum oxygen uptake, cardiac output and tissue substrate metabolism, respectively. Except for the direct Fick equation, all have been successfully used in pediatric studies. Relatively new techniques for the assessment of exercise training-induced adaptations in youths include the thoracic bioimpedance and the Modelflow method for cardiac output determination, and magnetic resonance spectroscopy for intramuscular and intrahepatic lipid content. Additional validation and reliability studies in pediatric populations are needed for some of these techniques (e.g. the Modelflow method). SUMMARY Most of the techniques used in adults appear not directly applicable to youths. A combination of techniques and/or the application of new, promising and easy to use ones, such as near-infrared spectroscopy and Laser Doppler flowmetry, may advance our knowledge in pediatric exercise science.
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Affiliation(s)
- George P Nassis
- Laboratory of Nutrition and Clinical Dietetics, Department of Nutrition and Dietetics, Harokopio University, Athens, Greece
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Carstensen M, Thomsen C, Gotzsche O, Holst JJ, Schrezenmeir J, Hermansen K. Differential postprandial lipoprotein responses in type 2 diabetic men with and without clinical evidence of a former myocardial infarction. Rev Diabet Stud 2005; 1:175-84. [PMID: 17491702 PMCID: PMC1783690 DOI: 10.1900/rds.2004.1.175] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Postprandial lipemia plays an important role in the development of coronary heart disease through an elevation of triglyceride-rich lipoproteins. In type 2 diabetic male subjects, our aim was to compare postprandial lipemia in a high-risk population with former myocardial infarction (MI) with that of a lower risk population free of clinically detectable heart disease. 32 male type 2 diabetic subjects were included in the study. We matched 17 cases with a verified history of MI with 15 controls according to age, BMI, HbA1c, diabetes duration, smoking, and treatment of diabetes. Ongoing metformin, insulin, or lipid lowering pharmacological treatment were exclusion criteria. After a maximal exercise tolerance test and echocardiography, the subjects underwent a hyperinsulinemic, euglycemic clamp and a vitamin A fat loading test. Plasma triglyceride levels in the case group were significantly higher after 360 minutes (4.6 +/- 3.1 vs. 2.8 +/- 1.8 mmol/l, p = 0.04) and 480 minutes (3.6 +/- 2.2 vs. 2.4 +/- 2.4 mmol/l, p = 0.03), as was the incremental Area Under the Curve (iAUC) for the whole period (560 +/- 452 vs. 297 +/- 214 mmol x 480 min./l; p = 0.048). In addition, the retinyl palmitate responses in the chylomicron-fraction from the case group were significantly higher (iAUC 311,502 +/- 194,933 vs. 187,004 +/- 102,928 ng x 480 min./ml; p = 0.035). Type 2 diabetic males with prior MI had higher postprandial triglyceride-rich lipoprotein responses than those without MI, indicating that high responses may be a marker for a high-risk population.
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Affiliation(s)
- Marius Carstensen
- Department of Endocrinology and Metabolism C, Aarhus University Hospital, Aarhus Sygehus THG, Tage-Hansens Gade 2, DK-8000 Aarhus, Denmark.
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Abstract
OBJECTIVE To review the definition and prevalence of two insulin resistance (IR)-associated phenotypes, polycystic ovary syndrome (PCOS) and type 2 diabetes mellitus, as well as the risk and nature of their simultaneous presentation. DESIGN Review of published literature. RESULT(S) Insulin resistance affects between 10% and 25% of the general population. Two common disorders frequently associated with IR are PCOS, affecting 4% to 6% of reproductive-aged women, and type 2 diabetes mellitus, which is observed in about 2% to 6% of similarly aged women. Overall, about 50% to 70% of women with PCOS and 80% to 100% of patients with type 2 diabetes mellitus have variable degrees of IR. Insulin resistance and its secondary hyperinsulinemia appear to underlie many of the endocrine features of PCOS in a large proportion of such patients. The risk of type 2 diabetes mellitus among PCOS patients is 5- to 10-fold higher than normal. In turn, the risk of PCOS among reproductive-aged type 2 diabetes mellitus patients appears to be similarly increased. CONCLUSION(S) It remains to be determined whether PCOS and type 2 diabetes mellitus represent no more than different clinical manifestations of the same IR syndrome, with their phenotypic differences due to the presence or absence of a coincidental genetic defect at the level of the ovary or pancreas, respectively, or representing the result of etiologically different subtypes of IR syndromes.
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Affiliation(s)
- Fernando Ovalle
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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