1
|
Tomoo K, Szramowski M, Pinal R, Meyer JM, Zhang Y, Murray-Kolb LE, Henderson GC. Albumin is an important factor in the control of serum free fatty acid flux in both male and female mice. J Appl Physiol (1985) 2024; 136:1065-1075. [PMID: 38482577 DOI: 10.1152/japplphysiol.00894.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/22/2024] [Accepted: 03/08/2024] [Indexed: 04/30/2024] Open
Abstract
Albumin knockout (Alb-/-) mice exhibit a low plasma free fatty acid (FFA) concentration, but it was not known if the suppressed concentration reflects a lower rate of appearance (Ra) of FFA in the circulation (i.e., lower FFA flux) or if the absence of albumin alters the relationship between FFA flux and concentration. For understanding the role of albumin in FFA transport through the bloodstream, it is not sufficient to rely on FFA concentration data alone. Therefore, we developed a method to study FFA kinetics in Alb-/- mice. Using an albumin-free formulation of [U-13C]palmitate tracer, serum FFA kinetics were tested in Alb-/- and wild-type (WT) mice. Results indicate that the flux of FFA in serum of Alb-/- mice was significantly lower than in WT mice (P < 0.05), while albumin deficiency did not alter the relationship between FFA flux and concentration. Next, to test if suppressed lipolysis might have also been involved in the suppressed FFA kinetics, gene expression of a lipolytic enzyme (adipose triglyceride lipase, Atgl) and a marker of lipolysis (phosphorylation of hormone-sensitive lipase, p-HSL) were measured in adipose tissue. In contrast to the low FFA flux in Alb-/-, both Atgl gene expression and p-HSL protein were significantly higher in adipose tissue of Alb-/- than in WT mice (P < 0.05). Thus, the low FFA flux in Alb-/- appeared to be driven by the absence of albumin's FFA binding functions rather than through regulation of lipolysis, indicating that albumin is an important factor in determining the flux of FFA in circulation.NEW & NOTEWORTHY To improve understanding of the albumin protein's function in vivo, we tested plasma free fatty acid kinetics in albumin knockout mice compared with wild-type mice. Using a new tracer formulation strategy, it was discovered that the appearance rate of free fatty acids in serum is lower in albumin knockout mice than in wild-type mice. The results indicate that albumin is a major controller of free fatty acid kinetics.
Collapse
Affiliation(s)
- Keigo Tomoo
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana, United States
| | - Mirandia Szramowski
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana, United States
| | - Rodolfo Pinal
- Department of Industrial and Molecular Pharmaceutics, Purdue University, West Lafayette, Indiana, United States
| | - Juliauna M Meyer
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana, United States
| | - Yi Zhang
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana, United States
| | - Laura E Murray-Kolb
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana, United States
| | - Gregory C Henderson
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana, United States
| |
Collapse
|
2
|
Nielsen S, Jensen MD. Insulin regulation of regional lipolysis in upper-body obese and lean humans. JCI Insight 2024; 9:e175629. [PMID: 38602778 PMCID: PMC11141918 DOI: 10.1172/jci.insight.175629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 04/03/2024] [Indexed: 04/13/2024] Open
Abstract
BACKGROUND Upper-body obesity (UBO) results in insulin resistance with regards to free fatty acid (FFA) release; how this differs by fat depot and sex between adults with UBO and lean adults is unknown. We tested the hypothesis that insulin suppression of FFA release from the splanchnic bed, leg fat, and upper-body nonsplanchnic (UBNS) adipose tissue would be impaired in UBO. METHODS Fourteen volunteers with UBO (7 men and 7 women) and 14 healthy volunteers with normal weight (7 men and 7 women) participated in studies that included femoral artery, femoral vein, and hepatic vein catheterization. We then measured leg and splanchnic plasma flow as well as FFA kinetics (using isotopic tracers) under overnight fasting as well as low- and high-dose insulin infusion using the insulin clamp technique. RESULTS We found the expected insulin resistance in UBO; the most quantitatively important difference between adults with UBO and lean adults was greater FFA release from UBNS adipose tissue when plasma insulin concentrations were in the postprandial, physiological range. There were obesity, but not sex, differences in the regulation of splanchnic FFA release and sex differences in the regulation of leg FFA release. CONCLUSION Reversing the defects in insulin-regulated UBNS adipose tissue FFA release would have the greatest effect on systemic FFA abnormalities in UBO. FUNDING These studies were supported by the US Public Health Service (grants DK45343 and DK40484), the Novo Nordic Foundation (grant NNF18OC0031804 and NNF16OC0021406), and the Independent Research Fund Denmark (grant 8020-00420B).
Collapse
Affiliation(s)
- Søren Nielsen
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota, USA
- Steno Diabetes Center, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | |
Collapse
|
3
|
Chondronikola M, Yoshino J, Ramaswamy R, Giardina JD, Laforest R, Wahl RL, Patterson BW, Mittendorfer B, Klein S. Very-low-density lipoprotein triglyceride and free fatty acid plasma kinetics in women with high or low brown adipose tissue volume and overweight/obesity. Cell Rep Med 2024; 5:101370. [PMID: 38232692 PMCID: PMC10829791 DOI: 10.1016/j.xcrm.2023.101370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 09/18/2023] [Accepted: 12/14/2023] [Indexed: 01/19/2024]
Abstract
Although a high amount of brown adipose tissue (BAT) is associated with low plasma triglyceride concentration, the mechanism responsible for this relationship in people is not clear. Here, we evaluate the interrelationships among BAT, very-low-density lipoprotein triglyceride (VLDL-TG), and free fatty acid (FFA) plasma kinetics during thermoneutrality in women with overweight/obesity who had a low (<20 mL) or high (≥20 mL) volume of cold-activated BAT (assessed by using positron emission tomography in conjunction with 2-deoxy-2-[18F]-fluoro-glucose). We find that plasma TG and FFA concentrations are lower and VLDL-TG and FFA plasma clearance rates are faster in women with high BAT than low BAT volume, whereas VLDL-TG and FFA appearance rates in plasma are not different between the two groups. These findings demonstrate that women with high BAT volume have lower plasma TG and FFA concentrations than women with low BAT volumes because of increased VLDL-TG and FFA clearance rates. This study was registered at ClinicalTrials.gov (NCT02786251).
Collapse
Affiliation(s)
- Maria Chondronikola
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA; Wellcome-MRC Institute of Metabolic Science-Metabolic Research Laboratories, Medical Research Council Metabolic Diseases Unit, University of Cambridge, Cambridge, UK; Department of Nutritional Sciences and Dietetics, Harokopio University of Athens, Kallithea, Greece.
| | - Jun Yoshino
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
| | - Raja Ramaswamy
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | | | - Richard Laforest
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Richard L Wahl
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Bruce W Patterson
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
| | - Bettina Mittendorfer
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
| | - Samuel Klein
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA; Sansum Diabetes Research Institute, Santa Barbara, CA, USA.
| |
Collapse
|
4
|
Magkos F, Fabbrini E, Patterson BW, Mittendorfer B, Klein S. Physiological interindividual variability in endogenous estradiol concentration does not influence adipose tissue and hepatic lipid kinetics in women. Eur J Endocrinol 2022; 187:391-398. [PMID: 35895691 PMCID: PMC9347062 DOI: 10.1530/eje-22-0410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 07/06/2022] [Indexed: 01/22/2023]
Abstract
Objective Increased triglyceride (TG) and apolipoprotein B-100 (apoB-100) concentrations in plasma are important risk factors for cardiovascular disease in women. Administration of some estrogen preparations raises plasma TG and apoB-100 concentrations by increasing hepatic very low-density lipoprotein (VLDL) TG and apoB-100 secretion rates. However, the influence of physiological variation in endogenous estradiol on VLDL-TG and VLDL-apoB-100 metabolism and on free fatty acid (FFA) release into plasma (the major source of fatty acids for VLDL-TG production) is not known. Design and methods We measured basal VLDL-TG, VLDL-apoB-100, and plasma FFA kinetics by using stable isotopically labeled tracers in 36 eumenorrheic, premenopausal women (age: 33 ± 2 years, BMI: 31 ± 1 kg/m2; mean ± s.e.m.) during the follicular phase of the menstrual cycle; participants were divided into two groups based on low (n = 18) or high (n = 18) plasma estradiol concentrations (defined as below or above the median value of 140 pmol/L in the whole group). Results Mean plasma estradiol concentration was >3-fold higher in the high-estradiol than in the low-estradiol group (299 ± 37 and 96 ± 7 pmol/L, P < 0.001); there was no difference in plasma progesterone concentrations between the two groups (P = 0.976). There were no significant differences in plasma FFA concentration, FFA rate of appearance in plasma, VLDL-TG and VLDL-apoB-100 concentrations, hepatic VLDL-TG and VLDL-apoB-100 secretion rates, VLDL-TG and VLDL-apoB-100 plasma clearance rates, and mean residence times (all P ≥ 0.45). No significant associations were found between plasma estradiol concentration and FFA, VLDL-TG, and VLDL-apoB-100 concentrations and kinetics (all P > 0.19). Conclusions Plasma estradiol concentration is not an important correlate of basal plasma FFA, VLDL-TG, and VLDL-apoB-100 kinetics in premenopausal women.
Collapse
Affiliation(s)
- Faidon Magkos
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Elisa Fabbrini
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Bruce W. Patterson
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Bettina Mittendorfer
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Samuel Klein
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA
| |
Collapse
|
5
|
Cao C, Koh HCE, Van Vliet S, Patterson BW, Reeds DN, Laforest R, Gropler RJ, Mittendorfer B. Increased plasma fatty acid clearance, not fatty acid concentration, is associated with muscle insulin resistance in people with obesity. Metabolism 2022; 132:155216. [PMID: 35577100 PMCID: PMC10424797 DOI: 10.1016/j.metabol.2022.155216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/24/2022] [Accepted: 05/10/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Although it is well-accepted that increased plasma free fatty acid (FFA) concentration causes lipid overload and muscle insulin resistance in people with obesity, plasma FFA concentration poorly predicts insulin-resistant glucose metabolism. It has been proposed that hyperinsulinemia in people with obesity sufficiently inhibits adipose tissue triglyceride lipolysis to prevent FFA-induced insulin resistance. However, we hypothesized enhanced FFA clearance in people with obesity, compared with lean people, prevents a marked increase in plasma FFA even when FFA appearance is high. METHODS We assessed FFA kinetics during basal conditions and during a hyperinsulinemic-euglycemic clamp procedure in 14 lean people and 46 people with obesity by using [13C]palmitate tracer infusion. Insulin-stimulated muscle glucose uptake rate was evaluated by dynamic PET-imaging of skeletal muscles after [18F]fluorodeoxyglucose injection. RESULTS Plasma FFA clearance was accelerated in participants with obesity and correlated negatively with muscle insulin sensitivity without a difference between lean and obese participants. Furthermore, insulin infusion increased FFA clearance and the increase was greater in obese than lean participants. CONCLUSIONS Our findings suggest plasma FFA extraction efficiency, not just plasma FFA concentration, is an important determinant of the cellular fatty acid load and the stimulatory effect of insulin on FFA clearance counteracts some of its antilipolytic effect.
Collapse
Affiliation(s)
- Chao Cao
- Center for Human Nutrition, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, United States of America
| | - Han-Chow E Koh
- Center for Human Nutrition, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, United States of America
| | - Stephan Van Vliet
- Center for Human Nutrition, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, United States of America
| | - Bruce W Patterson
- Center for Human Nutrition, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, United States of America
| | - Dominic N Reeds
- Center for Human Nutrition, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, United States of America
| | - Richard Laforest
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, United States of America
| | - Robert J Gropler
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, United States of America
| | - Bettina Mittendorfer
- Center for Human Nutrition, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO 63110, United States of America.
| |
Collapse
|
6
|
Koh HCE, van Vliet S, Pietka TA, Meyer GA, Razani B, Laforest R, Gropler RJ, Mittendorfer B. Subcutaneous Adipose Tissue Metabolic Function and Insulin Sensitivity in People With Obesity. Diabetes 2021; 70:2225-2236. [PMID: 34266892 PMCID: PMC8576507 DOI: 10.2337/db21-0160] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 07/08/2021] [Indexed: 11/13/2022]
Abstract
We used stable isotope-labeled glucose and palmitate tracer infusions, a hyperinsulinemic-euglycemic clamp, positron emission tomography of muscles and adipose tissue after [18F]fluorodeoxyglucose and [15O]water injections, and subcutaneous adipose tissue (SAT) biopsy to test the hypotheses that 1) increased glucose uptake in SAT is responsible for high insulin-stimulated whole-body glucose uptake in people with obesity who are insulin sensitive and 2) putative SAT factors thought to cause insulin resistance are present in people with obesity who are insulin resistant but not in those who are insulin sensitive. We found that high insulin-stimulated whole-body glucose uptake in insulin-sensitive participants with obesity was not due to channeling of glucose into SAT but, rather, was due to high insulin-stimulated muscle glucose uptake. Furthermore, insulin-stimulated muscle glucose uptake was not different between insulin-sensitive obese and lean participants even though adipocytes were larger, SAT perfusion and oxygenation were lower, and markers of SAT inflammation, fatty acid appearance in plasma in relation to fat-free mass, and plasma fatty acid concentration were higher in the insulin-sensitive obese than in lean participants. In addition, we observed only marginal or no differences in adipocyte size, SAT perfusion and oxygenation, and markers of SAT inflammation between insulin-resistant and insulin-sensitive obese participants. Plasma fatty acid concentration was also not different between insulin-sensitive and insulin-resistant obese participants, even though SAT was resistant to the inhibitory effect of insulin on lipolysis in the insulin-resistant obese group. These data suggest that several putative SAT factors commonly implicated in causing insulin resistance are normal consequences of SAT expansion unrelated to insulin resistance.
Collapse
Affiliation(s)
- Han-Chow E Koh
- Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO
| | - Stephan van Vliet
- Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO
| | - Terri A Pietka
- Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO
| | - Gretchen A Meyer
- Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO
| | - Babak Razani
- Division of Cardiology, Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Richard Laforest
- Department of Radiology, Washington University School of Medicine, St. Louis, MO
| | - Robert J Gropler
- Department of Radiology, Washington University School of Medicine, St. Louis, MO
| | - Bettina Mittendorfer
- Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO
| |
Collapse
|
7
|
Blocking endogenous IL-6 impairs mobilization of free fatty acids during rest and exercise in lean and obese men. CELL REPORTS MEDICINE 2021; 2:100396. [PMID: 34622233 PMCID: PMC8484687 DOI: 10.1016/j.xcrm.2021.100396] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 06/03/2021] [Accepted: 08/17/2021] [Indexed: 12/26/2022]
Abstract
Lack of interleukin-6 (IL-6) leads to expansion of adipose tissue mass in rodents and humans. The exact underlying mechanisms have not been identified. In this placebo-controlled, non-randomized, participant-blinded crossover study, we use the IL-6 receptor antibody tocilizumab to investigate the role of endogenous IL-6 in regulating systemic energy metabolism at rest and during exercise and recovery in lean and obese men using tracer dilution methodology. Tocilizumab reduces fatty acid appearance in the circulation under all conditions in lean and obese individuals, whereas lipolysis (the rate of glycerol appearance into the circulation) is mostly unaffected. The fact that fatty acid oxidation is unaffected by IL-6 receptor blockade suggests increased re-esterification of fatty acids. Glucose kinetics are unaffected. We find that blocking endogenous IL-6 signaling with tocilizumab impairs fat mobilization, which may contribute to expansion of adipose tissue mass and, thus, affect the health of individuals undergoing anti-IL-6 therapy (Clinicaltrials.gov: NCT03967691).
Collapse
|
8
|
Montastier É, Ye RZ, Noll C, Bouffard L, Fortin M, Frisch F, Phoenix S, Guérin B, Turcotte ÉE, Lewis GF, Carpentier AC. Increased postprandial nonesterified fatty acid efflux from adipose tissue in prediabetes is offset by enhanced dietary fatty acid adipose trapping. Am J Physiol Endocrinol Metab 2021; 320:E1093-E1106. [PMID: 33870714 DOI: 10.1152/ajpendo.00619.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The mechanism of increased postprandial nonesterified fatty acid (NEFA) appearance in the circulation in impaired glucose tolerance (IGT) is due to increased adipose tissue lipolysis but could also be contributed to by reduced adipose tissue (AT) dietary fatty acid (DFA) trapping and increased "spillover" into the circulation. Thirty-one subjects with IGT (14 women, 17 men) and 29 with normal glucose tolerance (NGT, 15 women, 14 men) underwent a meal test with oral and intravenous palmitate tracers and the oral [18F]-fluoro-thia-heptadecanoic acid positron emission tomography method. Postprandial palmitate appearance (Rapalmitate) was higher in IGT versus NGT (P < 0.001), driven exclusively by Rapalmitate from obesity-associated increase in intracellular lipolysis (P = 0.01), as Rapalmitate from DFA spillover was not different between the groups (P = 0.19) and visceral AT DFA trapping was even higher in IGT versus NGT (P = 0.02). Plasma glycerol appearance was lower in IGT (P = 0.01), driven down by insulin resistance and increased insulin secretion. Thus, we found higher AT DFA trapping, limiting spillover to lean organs and in part offsetting the increase in Rapalmitate from intracellular lipolysis. Whether similar findings occur in frank diabetes, a condition also characterized by insulin resistance but relative insulin deficiency, requires further investigation (Clinicaltrials.gov: NCT04088344, NCT02808182).NEW & NOTEWORTHY We found higher adipose tissue dietary fatty acid trapping, limiting spillover to lean organs, that in part offsets the increase in appearance rate of palmitate from intracellular lipolysis in prediabetes. These results point to the adaptive nature of adipose tissue trapping and dietary fatty acid spillover as a protective mechanism against excess obesity-related palmitate appearance rate from intracellular adipose tissue lipolysis.
Collapse
Affiliation(s)
- Émilie Montastier
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Run Zhou Ye
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Christophe Noll
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Lucie Bouffard
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Mélanie Fortin
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Frédérique Frisch
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | | | - Brigitte Guérin
- Department of Radiobiology and Nuclear Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Éric E Turcotte
- Department of Radiobiology and Nuclear Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Gary F Lewis
- Division of Endocrinology, Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - André C Carpentier
- Division of Endocrinology, Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| |
Collapse
|
9
|
Carpentier AC. 100 th anniversary of the discovery of insulin perspective: insulin and adipose tissue fatty acid metabolism. Am J Physiol Endocrinol Metab 2021; 320:E653-E670. [PMID: 33522398 DOI: 10.1152/ajpendo.00620.2020] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Insulin inhibits systemic nonesterified fatty acid (NEFA) flux to a greater degree than glucose or any other metabolite. This remarkable effect is mainly due to insulin-mediated inhibition of intracellular triglyceride (TG) lipolysis in adipose tissues and is essential to prevent diabetic ketoacidosis, but also to limit the potential lipotoxic effects of NEFA in lean tissues that contribute to the development of diabetes complications. Insulin also regulates adipose tissue fatty acid esterification, glycerol and TG synthesis, lipogenesis, and possibly oxidation, contributing to the trapping of dietary fatty acids in the postprandial state. Excess NEFA flux at a given insulin level has been used to define in vivo adipose tissue insulin resistance. Adipose tissue insulin resistance defined in this fashion has been associated with several dysmetabolic features and complications of diabetes, but the mechanistic significance of this concept is not fully understood. This review focusses on the in vivo regulation of adipose tissue fatty acid metabolism by insulin and the mechanistic significance of the current definition of adipose tissue insulin resistance. One hundred years after the discovery of insulin and despite decades of investigations, much is still to be understood about the multifaceted in vivo actions of this hormone on adipose tissue fatty acid metabolism.
Collapse
Affiliation(s)
- André C Carpentier
- Division of Endocrinology, Department of Medicine, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| |
Collapse
|
10
|
Akhigbe R, Ajayi A. The impact of reactive oxygen species in the development of cardiometabolic disorders: a review. Lipids Health Dis 2021; 20:23. [PMID: 33639960 PMCID: PMC7916299 DOI: 10.1186/s12944-021-01435-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 01/26/2021] [Indexed: 02/07/2023] Open
Abstract
Oxidative stress, an alteration in the balance between reactive oxygen species (ROS) generation and antioxidant buffering capacity, has been implicated in the pathogenesis of cardiometabolic disorders (CMD). At physiological levels, ROS functions as signalling mediators, regulates various physiological functions such as the growth, proliferation, and migration endothelial cells (EC) and smooth muscle cells (SMC); formation and development of new blood vessels; EC and SMC regulated death; vascular tone; host defence; and genomic stability. However, at excessive levels, it causes a deviation in the redox state, mediates the development of CMD. Multiple mechanisms account for the rise in the production of free radicals in the heart. These include mitochondrial dysfunction and uncoupling, increased fatty acid oxidation, exaggerated activity of nicotinamide adenine dinucleotide phosphate oxidase (NOX), reduced antioxidant capacity, and cardiac metabolic memory. The purpose of this study is to discuss the link between oxidative stress and the aetiopathogenesis of CMD and highlight associated mechanisms. Oxidative stress plays a vital role in the development of obesity and dyslipidaemia, insulin resistance and diabetes, hypertension via various mechanisms associated with ROS-led inflammatory response and endothelial dysfunction.
Collapse
Affiliation(s)
- Roland Akhigbe
- Department of Physiology, College of Medicine, Ladoke Akintola University of Technology, Ogbomoso, Oyo State Nigeria
- Reproductive Biology and Toxicology Research Laboratories, Oasis of Grace Hospital, Osogbo, Osun State Nigeria
- Department of Chemical Sciences, Kings University, Odeomu, Osun Nigeria
| | - Ayodeji Ajayi
- Department of Physiology, College of Medicine, Ladoke Akintola University of Technology, Ogbomoso, Oyo State Nigeria
| |
Collapse
|
11
|
Circulating Non-Esterified Fatty Acids as Biomarkers for Fat Content and Composition in Pigs. Animals (Basel) 2021; 11:ani11020386. [PMID: 33546411 PMCID: PMC7913534 DOI: 10.3390/ani11020386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/27/2021] [Accepted: 01/29/2021] [Indexed: 12/16/2022] Open
Abstract
Simple Summary Circulating non-esterified fatty acids (NEFA) may be valuable as biomarkers for intramuscular fat content and fatty acid composition, as well as for other meat quality traits, in finishing heavy Duroc pigs. However, circulating NEFA composition may be affected by other factors such as age, fasting duration, and genetic variants related with adipogenesis and fatty acid metabolism pathways (e.g., SCD and LEPR). This study revealed that the circulating NEFA composition, especially the oleic acid content, reflects the metabolic status of an animal at a given time but has limited value as biomarker of intramuscular fat content and fatty acid composition. Abstract Circulating non-esterified fatty acids (NEFA) can reflect the composition of dietary fat or adipose tissues depending on the fasting conditions. Therefore, circulating NEFA may be valuable as biomarkers for meat quality traits, such as intramuscular fat content and fatty acid composition in finishing pigs. Genetic variants that regulate lipid metabolism can also modulate the circulating NEFA. We conducted an experiment with 150 heavy Duroc pigs to evaluate fluctuations in the circulating NEFA composition due to age, fasting duration and two genetic polymorphisms, one in the leptin receptor (LEPR; rs709596309) and one in the stearoyl-CoA desaturase (SCD; rs80912566) gene. Circulating NEFA were more saturated and less monounsaturated than the subcutaneous and intramuscular adipose tissues. Absolute circulating NEFA content was more influenced by fasting duration than age. The SCD polymorphism did not impact NEFA content or composition. The LEPR polymorphism affected the content but not the fatty acid composition. Circulating oleic acid NEFA content after a short fasting was positively correlated with intramuscular fat content and, after a long fasting, with intramuscular oleic acid content. We conclude that circulating NEFA reflect environmental and genetic metabolic changes but are of limited value as biomarkers for intramuscular fat content and fatty acid composition.
Collapse
|
12
|
Adipocytes promote breast tumorigenesis through TAZ-dependent secretion of Resistin. Proc Natl Acad Sci U S A 2020; 117:33295-33304. [PMID: 33318171 PMCID: PMC7776784 DOI: 10.1073/pnas.2005950117] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Adipocytes are the most abundant and perhaps most active components of the tumor microenvironment in obese individuals that potentiate breast tumorigenesis through secretory mechanisms. The modulation of adipocytes can be novel therapy targets for breast cancer. Here, we revealed a specific upregulation of adipocytic TAZ through the FFA/PPARγ axis in diet-induced adiposity. Adipocytic TAZ knockdown or deficiency in mice inhibits adipocyte-induced breast cancer proliferation and stemness through impaired expression and secretion of Resistin. Immunostaining in triple-negative breast cancer samples showed that higher adipocytic TAZ/Resistin expression associates with higher clinical stages and poorer survival, demonstrating promising therapeutic targets. Adipocytes have been implicated in breast tumor growth and stemness maintenance through secreted factors. However, the mechanisms by which these cytokines are regulated during diet-induced obesity and contribute to breast tumorigenesis remain largely unknown. Here we show that transcription cofactor TAZ in adipocytes is directly up-regulated by the free fatty acid/PPARγ axis upon dietary fat stimulation. TAZ knockdown alters the expression profile of a series of secreted proteins and attenuates the tumor-supporting function of adipocytes. Moreover, we identify Resistin, an adipose-derived hormone, as a functional downstream target of TAZ, which facilitates tumorigenesis, and its expression correlated with adipocyitc TAZ in triple-negative breast cancer samples. Further, Adiponectin-cre–mediated TAZ knockout in adipocytes mitigates breast tumor growth. Taken together, our findings highlight how diet-induced TAZ expression in adipocytes promotes tumorigenesis, suggesting promising cancer therapeutic targets.
Collapse
|
13
|
van Vliet S, Koh HCE, Patterson BW, Yoshino M, LaForest R, Gropler RJ, Klein S, Mittendorfer B. Obesity Is Associated With Increased Basal and Postprandial β-Cell Insulin Secretion Even in the Absence of Insulin Resistance. Diabetes 2020; 69:2112-2119. [PMID: 32651241 PMCID: PMC7506835 DOI: 10.2337/db20-0377] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/01/2020] [Indexed: 12/18/2022]
Abstract
We tested the hypothesis that obesity, independent of insulin resistance, is associated with increased insulin secretion. We compared insulin kinetics before and after glucose ingestion in lean healthy people and people with obesity who were matched on multiorgan insulin sensitivity (inhibition of adipose tissue lipolysis and glucose production and stimulation of muscle glucose uptake) as assessed by using a two-stage hyperinsulinemic-euglycemic pancreatic clamp procedure in conjunction with glucose and palmitate tracer infusions and positron emission tomography. We also evaluated the effect of diet-induced weight loss on insulin secretion in people with obesity who did not improve insulin sensitivity despite marked (∼20%) weight loss. Basal and postprandial insulin secretion rates were >50% greater in people with obesity than lean people even though insulin sensitivity was not different between groups. Weight loss in people with obesity decreased insulin secretion by 35% even though insulin sensitivity did not change. These results demonstrate that increased insulin secretion in people with obesity is associated with excess adiposity itself and is not simply a compensatory response to insulin resistance. These findings have important implications regarding the pathogenesis of diabetes because hyperinsulinemia causes insulin resistance and insulin hypersecretion is an independent risk factor for developing diabetes.
Collapse
Affiliation(s)
- Stephan van Vliet
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Han-Chow E Koh
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Bruce W Patterson
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Mihoko Yoshino
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Richard LaForest
- Mallinckrodt Institute of Radiology at Washington University School of Medicine, St. Louis, MO
| | - Robert J Gropler
- Mallinckrodt Institute of Radiology at Washington University School of Medicine, St. Louis, MO
| | - Samuel Klein
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Bettina Mittendorfer
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| |
Collapse
|
14
|
van Vliet S, Fappi A, Reeds DN, Mittendorfer B. No independent or combined effects of vitamin D and conjugated linoleic acids on muscle protein synthesis in older adults: a randomized, double-blind, placebo-controlled clinical trial. Am J Clin Nutr 2020; 112:1382-1389. [PMID: 32860399 PMCID: PMC7657331 DOI: 10.1093/ajcn/nqaa240] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/30/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Aging is associated with skeletal muscle anabolic resistance (i.e., reduced muscle protein synthesis during anabolic conditions such as hyperaminoacidemia). The results from studies conducted in cell culture systems and animals suggest that both vitamin D and conjugated linoleic acids (CLAs) stimulate muscle protein synthesis. OBJECTIVES To conduct a randomized, double-blind, placebo-controlled clinical trial to determine the independent and combined effects of dietary vitamin D and CLA supplementation on myofibrillar protein synthesis rates in sedentary older adults. METHODS Thirty-two sedentary, older adults were randomized to receive either: 1) 2000 IU vitamin D-3 (Vit D) per day; 2) 4000 mg CLA per day; 3) both Vit D (2000 IU/d) and CLA (4000 mg/d); or 4) placebo for 8 wk. Myofibrillar protein synthesis rates were evaluated by using intravenous [ring-2H5]phenylalanine infusion in conjunction with muscle biopsies during basal, postabsorptive conditions and during combined amino acid and insulin infusion before and after the supplementation period. RESULTS Before the intervention, basal myofibrillar protein synthesis rates were not different among groups (Placebo: 0.033 ± 0.003; Vit D: 0.034 ± 0.002; CLA: 0.029 ± 0.005; Vit D + CLA: 0.038 ± 0.005 %·h-1), and hyperinsulinemia-hyperaminoacidemia increased myofibrillar protein synthesis rates by ∼35%. Compared with placebo, neither Vit D nor CLA nor combined Vit D + CLA supplementation affected the basal myofibrillar protein synthesis rates (placebo: 0.040 ± 0.004%/h; Vit D: 0.044 ± 0.006%/h; CLA: 0.039 ± 0.006%/h; Vit D + CLA: 0.040 ± 0.007%/h) or the hyperinsulinemia-hyperaminoacidemia-induced increase in myofibrillar protein synthesis (percentage increase from basal before and after the interventions: placebo, 30 ± 11 and 36 ± 11; Vit D, 38 ± 8 and 34 ± 10; CLA, 50 ± 14 and 51 ± 16; Vit D + CLA, 29 ± 15 and 35 ± 8). CONCLUSIONS Vitamin D and/or CLA supplementation, at the doses provided in our study, does not have muscle anabolic effects in sedentary older adults.The study was registered at clinicaltrials.gov (NCT03115775).
Collapse
Affiliation(s)
- Stephan van Vliet
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Alan Fappi
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Dominic N Reeds
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | | |
Collapse
|
15
|
Fappi A, Mittendorfer B. Different physiological mechanisms underlie an adverse cardiovascular disease risk profile in men and women. Proc Nutr Soc 2020; 79:210-218. [PMID: 31340878 PMCID: PMC7583670 DOI: 10.1017/s0029665119001022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CVD affect about one-third of the population and are the leading cause of mortality. The prevalence of CVD is closely linked to the prevalence of obesity because obesity is commonly associated with metabolic abnormalities that are important risk factors for CVD, including insulin resistance, pre-diabetes, and type-2 diabetes, atherosclerotic dyslipidaemia, endothelial dysfunction and hypertension. Women have a more beneficial traditional CVD risk profile (lower fasting plasma glucose, less atherogenic lipid profile) and a lower absolute risk for CVD than men. However, the relative risk for CVD associated with hyperglycaemia and dyslipidaemia is several-fold higher in women than in men. The reasons for the sex differences in CVD risk associated with metabolic abnormalities are unclear but could be related to differences in the mechanisms that cause hyperglycaemia and dyslipidaemia in men and women, which could influence the pathogenic processes involved in CVD. In the present paper, we review the influence of a person's sex on key aspects of metabolism involved in the cardiometabolic disease process, including insulin action on endogenous glucose production, tissue glucose disposal, and adipose tissue lipolysis, insulin secretion and insulin plasma clearance, postprandial glucose, fatty acid, and triglyceride kinetics, hepatic lipid metabolism and myocardial substrate use. We conclude that there are marked differences in many aspects of metabolism in men and women that are not all attributable to differences in the sex hormone milieu. The mechanisms responsible for these differences and the clinical implications of these observations are unclear and require further investigation.
Collapse
Affiliation(s)
- Alan Fappi
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
| | - Bettina Mittendorfer
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
| |
Collapse
|
16
|
Mey JT, Hari A, Axelrod CL, Fealy CE, Erickson ML, Kirwan JP, Dweik RA, Heresi GA. Lipids and ketones dominate metabolism at the expense of glucose control in pulmonary arterial hypertension: a hyperglycaemic clamp and metabolomics study. Eur Respir J 2020; 55:13993003.01700-2019. [PMID: 32108049 PMCID: PMC7263739 DOI: 10.1183/13993003.01700-2019] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 01/18/2020] [Indexed: 12/31/2022]
Abstract
Individuals with idiopathic pulmonary arterial hypertension (PAH) display reduced oral glucose tolerance. This may involve defects in pancreatic function or insulin sensitivity but this hypothesis has not been tested; moreover, fasting nutrient metabolism remains poorly described in PAH. Thus, we aimed to characterise fasting nutrient metabolism and investigated the metabolic response to hyperglycaemia in PAH.12 participants (six PAH, six controls) were administered a hyperglycaemic clamp, while 52 (21 PAH, 31 controls) underwent plasma metabolomic analysis. Glucose, insulin, C-peptide, free fatty acids and acylcarnitines were assessed from the clamp. Plasma metabolomics was conducted on fasting plasma samples.The clamp verified a reduced insulin response to hyperglycaemia in PAH (-53% versus control), but with similar pancreatic insulin secretion. Skeletal muscle insulin sensitivity was unexpectedly greater in PAH. Hepatic insulin extraction was elevated in PAH (+11% versus control). Plasma metabolomics identified 862 metabolites: 213 elevated, 145 reduced in PAH (p<0.05). In both clamp and metabolomic cohorts, lipid oxidation and ketones were elevated in PAH. Insulin sensitivity, fatty acids, acylcarnitines and ketones correlated with PAH severity, while hepatic extraction and fatty acid:ketone ratio correlated with longer six-min walk distance.Poor glucose control in PAH could not be explained by pancreatic β-cell function or skeletal muscle insulin sensitivity. Instead, elevated hepatic insulin extraction emerged as an underlying factor. In agreement, nutrient metabolism in PAH favours lipid and ketone metabolism at the expense of glucose control. Future research should investigate the therapeutic potential of reinforcing lipid and ketone metabolism on clinical outcomes in PAH.
Collapse
Affiliation(s)
- Jacob T. Mey
- Integrative Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA,Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland OH
| | - Adithya Hari
- Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland OH
| | - Christopher L. Axelrod
- Integrative Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA,Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland OH,Department of Translational Services, Pennington Biomedical Research Center, Baton Rouge, LA
| | - Ciarán E. Fealy
- Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland OH,Diabetes and Metabolism Research Group, Maastricht University, Maastricht, Netherlands,Metabolic Translational Research Center, Endocrinology & Metabolism Institute, Cleveland Clinic, Cleveland, OH
| | - Melissa L. Erickson
- Integrative Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA,Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland OH
| | - John P. Kirwan
- Integrative Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA,Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland OH,Metabolic Translational Research Center, Endocrinology & Metabolism Institute, Cleveland Clinic, Cleveland, OH
| | - Raed A. Dweik
- Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland OH,Department of Pulmonary Care and Critical Medicine, Respiratory Institute, Cleveland Clinic, Cleveland, OH
| | - Gustavo A. Heresi
- Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland OH,Department of Pulmonary Care and Critical Medicine, Respiratory Institute, Cleveland Clinic, Cleveland, OH
| |
Collapse
|
17
|
Walker RE, Ford JL, Boston RC, Savinova OV, Harris WS, Green MH, Shearer GC. Trafficking of nonesterified fatty acids in insulin resistance and relationship to dysglycemia. Am J Physiol Endocrinol Metab 2020; 318:E392-E404. [PMID: 31910030 PMCID: PMC7099405 DOI: 10.1152/ajpendo.00331.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In adipose, insulin functions to suppress intracellular lipolysis and secretion of nonesterified fatty acid (NEFA) into plasma. We applied glucose and NEFA minimal models (MM) following a frequently sampled intravenous glucose tolerance test (FSIVGTT) to assess glucose-specific and NEFA-specific insulin resistance. We used total NEFA and individual fatty acids in the NEFA MM, comparing the model parameters in metabolic syndrome (MetSyn) subjects (n = 52) with optimally healthy controls (OptHC; n = 14). Results are reported as mean difference (95% confidence interval). Using the glucose MM, MetSyn subjects had lower [-73% (-82, -57)] sensitivity to insulin (Si) and higher [138% (44, 293)] acute insulin response to glucose (AIRg). Using the NEFA MM, MetSyn subjects had lower [-24% (-35, -13)] percent suppression, higher [32% (15, 52)] threshold glucose (gs), and a higher [81% (12, 192)] affinity constant altering NEFA secretion (ϕ). Comparing fatty acids, percent suppression was lower in myristic acid (MA) than in all other fatty acids, and the stearic acid (SA) response was so unique that it did not fit the NEFA MM. MA and SA percent of total were increased at 50 min after glucose injection, whereas oleic acid (OA) and palmitic acid (PA) were decreased (P < 0.05). We conclude that the NEFA MM, as well as the response of individual NEFA fatty acids after a FSIVGTT, differ between OptHC and MetSyn subjects and that the NEFA MM parameters differ between individual fatty acids.
Collapse
Affiliation(s)
- Rachel E Walker
- Department of Nutritional Sciences; The Pennsylvania State University, University Park, Pennsylvania
| | - Jennifer L Ford
- Department of Nutritional Sciences; The Pennsylvania State University, University Park, Pennsylvania
| | - Raymond C Boston
- Department of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Olga V Savinova
- Sanford Research/University of South Dakota, Sioux Falls, South Dakota
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York
| | - William S Harris
- Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota
| | - Michael H Green
- Department of Nutritional Sciences; The Pennsylvania State University, University Park, Pennsylvania
| | - Gregory C Shearer
- Department of Nutritional Sciences; The Pennsylvania State University, University Park, Pennsylvania
- Sanford Research/University of South Dakota, Sioux Falls, South Dakota
- Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota
| |
Collapse
|
18
|
Wanders RJA, Vaz FM, Ferdinandusse S, van Kuilenburg ABP, Kemp S, van Karnebeek CD, Waterham HR, Houtkooper RH. Translational Metabolism: A multidisciplinary approach towards precision diagnosis of inborn errors of metabolism in the omics era. J Inherit Metab Dis 2019; 42:197-208. [PMID: 30723938 DOI: 10.1002/jimd.12008] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/27/2018] [Accepted: 10/11/2018] [Indexed: 12/19/2022]
Abstract
The laboratory diagnosis of inborn errors of metabolism has been revolutionized in recent years, thanks to the amazing developments in the field of DNA sequencing including whole exome and whole genome sequencing (WES and WGS). Interpretation of the results coming from WES and/or WGS analysis is definitely not trivial especially since the biological relevance of many of the variants identified by WES and/or WGS, have not been tested experimentally and prediction programs like POLYPHEN-2 and SIFT are far from perfect. Correct interpretation of WES and/or WGS results can only be achieved by performing functional studies at multiple levels (different metabolomics platforms, enzymology, in vitro and in vivo flux analysis), often requires studies in model organisms like zebra fish, Caenorhabditis elegans, Saccharomyces cerevisiae, mutant mice and others, and also requires the input of many different disciplines to make this Translational Metabolism approach effective.
Collapse
Affiliation(s)
- Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Frederic M Vaz
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - André B P van Kuilenburg
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Stephan Kemp
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Clara D van Karnebeek
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
19
|
Zhang L, Su S, Zhu Y, Guo J, Guo S, Qian D, Ouyang Z, Duan JA. Mulberry leaf active components alleviate type 2 diabetes and its liver and kidney injury in db/db mice through insulin receptor and TGF-β/Smads signaling pathway. Biomed Pharmacother 2019; 112:108675. [PMID: 30780108 DOI: 10.1016/j.biopha.2019.108675] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/06/2019] [Accepted: 02/06/2019] [Indexed: 01/08/2023] Open
Abstract
Mulberry leaf is one of the commonly used traditional Chinese medicines, has been shown to exert hypoglycemic effects against diabetes. The aim of this study is to investigate the effects and mechanism of mulberry leaf flavonoids (MF), polysaccharides (MP) and alkaloids (MA) on diabetic and its liver and kidney injury. The db/db mice was adopted and the results showed that the FBG (fasting blood glucose) of model group continued to increase and associated liver and kidney injury. After the intervention of MP and MA, the value of FBG exhibited the most obvious hypoglycemic effect. MF and MP have obvious improved effect on kidney injury, which reduced the content of mALB/Cre (microalbumin/creatinine) in urine and improved the tubular epithelial cells edematous and renal cystic epithelial thickening. While the MF and MA possessed a significant effect on liver damage, manifested in reducing the levels of ALT (alanine aminotransferase) and AST (aspartate aminotransferase) and pathological changes of liver on db/db mice. Through metabolomics analysis, 13 endogenous potential biomarkers were identified in serum. The three effective components of mulberry can regulate the 13 potential biomarkers and the corresponding metabolic pathway. Collectively, the components of mulberry leaf have clear hypoglycemic effect and protective effect on liver and kidney injury and the effects are related to insulin receptor and TGF-β/Smads signaling pathway.
Collapse
Affiliation(s)
- Liwen Zhang
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Key Laboratory of Chinese Medicinal Resources Recycling Utilization, State Administration of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Shulan Su
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Key Laboratory of Chinese Medicinal Resources Recycling Utilization, State Administration of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Yue Zhu
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Key Laboratory of Chinese Medicinal Resources Recycling Utilization, State Administration of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Jianming Guo
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Key Laboratory of Chinese Medicinal Resources Recycling Utilization, State Administration of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Sheng Guo
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Key Laboratory of Chinese Medicinal Resources Recycling Utilization, State Administration of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Dawei Qian
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Key Laboratory of Chinese Medicinal Resources Recycling Utilization, State Administration of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Zhen Ouyang
- College of Pharmacy, Jiangsu University, Zhenjiang 210013, China
| | - Jin-Ao Duan
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Key Laboratory of Chinese Medicinal Resources Recycling Utilization, State Administration of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| |
Collapse
|
20
|
Green CJ, Parry SA, Gunn PJ, Ceresa CDL, Rosqvist F, Piché ME, Hodson L. Studying non-alcoholic fatty liver disease: the ins and outs of in vivo, ex vivo and in vitro human models. Horm Mol Biol Clin Investig 2018; 41:/j/hmbci.ahead-of-print/hmbci-2018-0038/hmbci-2018-0038.xml. [PMID: 30098284 DOI: 10.1515/hmbci-2018-0038] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/22/2018] [Indexed: 02/07/2023]
Abstract
The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing. Determining the pathogenesis and pathophysiology of human NAFLD will allow for evidence-based prevention strategies, and more targeted mechanistic investigations. Various in vivo, ex situ and in vitro models may be utilised to study NAFLD; but all come with their own specific caveats. Here, we review the human-based models and discuss their advantages and limitations in regards to studying the development and progression of NAFLD. Overall, in vivo whole-body human studies are advantageous in that they allow for investigation within the physiological setting, however, limited accessibility to the liver makes direct investigations challenging. Non-invasive imaging techniques are able to somewhat overcome this challenge, whilst the use of stable-isotope tracers enables mechanistic insight to be obtained. Recent technological advances (i.e. normothermic machine perfusion) have opened new opportunities to investigate whole-organ metabolism, thus ex situ livers can be investigated directly. Therefore, investigations that cannot be performed in vivo in humans have the potential to be undertaken. In vitro models offer the ability to perform investigations at a cellular level, aiding in elucidating the molecular mechanisms of NAFLD. However, a number of current models do not closely resemble the human condition and work is ongoing to optimise culturing parameters in order to recapitulate this. In summary, no single model currently provides insight into the development, pathophysiology and progression across the NAFLD spectrum, each experimental model has limitations, which need to be taken into consideration to ensure appropriate conclusions and extrapolation of findings are made.
Collapse
Affiliation(s)
- Charlotte J Green
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Siôn A Parry
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Pippa J Gunn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Carlo D L Ceresa
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Fredrik Rosqvist
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden
| | - Marie-Eve Piché
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Quebec Heart and Lung Institute, Laval University, Quebec, Canada
| | - Leanne Hodson
- University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital,Old Road Headington, Oxford OX3 7LE, United Kingdom of Great Britain and Northern Ireland
| |
Collapse
|
21
|
Samovski D, Dhule P, Pietka T, Jacome-Sosa M, Penrose E, Son NH, Flynn CR, Shoghi KI, Hyrc KL, Goldberg IJ, Gamazon ER, Abumrad NA. Regulation of Insulin Receptor Pathway and Glucose Metabolism by CD36 Signaling. Diabetes 2018; 67:1272-1284. [PMID: 29748289 PMCID: PMC6014550 DOI: 10.2337/db17-1226] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 04/26/2018] [Indexed: 12/19/2022]
Abstract
During reduced energy intake, skeletal muscle maintains homeostasis by rapidly suppressing insulin-stimulated glucose utilization. Loss of this adaptation is observed with deficiency of the fatty acid transporter CD36. A similar loss is also characteristic of the insulin-resistant state where CD36 is dysfunctional. To elucidate what links CD36 to muscle glucose utilization, we examined whether CD36 signaling might influence insulin action. First, we show that CD36 deletion specific to skeletal muscle reduces expression of insulin signaling and glucose metabolism genes. It decreases muscle ceramides but impairs glucose disposal during a meal. Second, depletion of CD36 suppresses insulin signaling in primary-derived human myotubes, and the mechanism is shown to involve functional CD36 interaction with the insulin receptor (IR). CD36 promotes tyrosine phosphorylation of IR by the Fyn kinase and enhances IR recruitment of P85 and downstream signaling. Third, pretreatment for 15 min with saturated fatty acids suppresses CD36-Fyn enhancement of IR phosphorylation, whereas unsaturated fatty acids are neutral or stimulatory. These findings define mechanisms important for muscle glucose metabolism and optimal insulin responsiveness. Potential human relevance is suggested by genome-wide analysis and RNA sequencing data that associate genetically determined low muscle CD36 expression to incidence of type 2 diabetes.
Collapse
Affiliation(s)
- Dmitri Samovski
- Departments of Medicine and Cell Biology, Washington University in St. Louis, St. Louis, MO
| | - Pallavi Dhule
- Departments of Medicine and Cell Biology, Washington University in St. Louis, St. Louis, MO
| | - Terri Pietka
- Departments of Medicine and Cell Biology, Washington University in St. Louis, St. Louis, MO
| | - Miriam Jacome-Sosa
- Departments of Medicine and Cell Biology, Washington University in St. Louis, St. Louis, MO
| | - Eric Penrose
- Departments of Medicine and Cell Biology, Washington University in St. Louis, St. Louis, MO
| | - Ni-Huiping Son
- Division of Endocrinology, Diabetes and Metabolism, New York University School of Medicine, New York, NY
| | | | - Kooresh I Shoghi
- Department of Radiology, Washington University in St. Louis, St. Louis, MO
| | - Krzysztof L Hyrc
- Alafi Neuroimaging Laboratory, Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO
| | - Ira J Goldberg
- Division of Endocrinology, Diabetes and Metabolism, New York University School of Medicine, New York, NY
| | - Eric R Gamazon
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Clare Hall, University of Cambridge, Cambridge, U.K
| | - Nada A Abumrad
- Departments of Medicine and Cell Biology, Washington University in St. Louis, St. Louis, MO
| |
Collapse
|
22
|
Bouchouirab FZ, Fortin M, Noll C, Dubé J, Carpentier AC. Plasma Palmitoyl-Carnitine (AC16:0) Is a Marker of Increased Postprandial Nonesterified Incomplete Fatty Acid Oxidation Rate in Adults With Type 2 Diabetes. Can J Diabetes 2017; 42:382-388.e1. [PMID: 29129455 DOI: 10.1016/j.jcjd.2017.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 09/06/2017] [Accepted: 09/06/2017] [Indexed: 01/15/2023]
Abstract
OBJECTIVES Enhanced mitochondrial fatty acid utilization is known to increase radical oxidative stress and induce insulin resistance. An increased level of plasma acylcarnitine (AC) has been proposed to indicate mitochondrial energy substrate overload, a possible mechanism leading to insulin resistance. The aim of our study was to determine fasting and postprandial plasma acetyl-carnitine (AC2:0), palmitoyl-carnitine (AC16:0), oleoyl-carnitine (AC18:1) and linoleoyl-carnitine (AC18:2) levels and their relationships with plasma nonesterified fatty acid appearance and oxidation rates and insulin sensitivity in participants with type 2 diabetes and normoglycemic offspring of 2 parents with type 2 diabetes (FH+) compared to healthy participants without family histories of type 2 diabetes (FH-). METHODS All participants underwent 3 metabolic protocols: 1) a euglycemic hyperinsulinemic clamp at fasting; 2) a 6-hour steady-state oral standard liquid meal and 3) an identical 6-hour steady-state meal intake study with a euglycemic hyperinsulinemic clamp. AC levels were measured by liquid chromatography with tandem mass spectrometry, and fatty acid oxidation (FAO) rates were measured by stable isotopic tracer techniques with indirect respiratory calorimetry. RESULTS During the insulin clamp at fasting, AC16:0 was significantly higher in the group with type 2 diabetes vs. FH- (p<0.05). In the postprandial state, AC2:0, AC16:0 and AC18:1 decreased significantly, but this reduction was blunted in type 2 diabetes, even during normalization of postprandial glucose levels during the insulin clamp. Fasting AC16:0 correlated with FAO (ρ=+0.604; p=0.0002); triacylglycerol (ρ=+0.427; p<0.02) and waist circumference (ρ=+0.416; p=0.02). CONCLUSIONS Spillover of AC occurs in type 2 diabetes but is not fully established in FH+. AC16:0 can be a useful biomarker of excessive FAO.
Collapse
Affiliation(s)
- Fatima-Zahra Bouchouirab
- Division of Biochemistry, Department of Medical Biology, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - Mélanie Fortin
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - Christophe Noll
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - Jean Dubé
- Division of Biochemistry, Department of Medical Biology, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - André C Carpentier
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada.
| |
Collapse
|
23
|
Abstract
PURPOSE OF REVIEW Abdominal obesity is associated with a number of important metabolic abnormalities including liver steatosis, insulin resistance and an atherogenic lipoprotein profile (termed dyslipidemia). The purpose of this review is to highlight recent progress in understanding the pathogenesis of this dyslipidemia. RECENT FINDINGS Recent results from kinetic studies using stable isotopes indicate that the hypertriglyceridemia associated with abdominal obesity stems from dual mechanisms: (1) enhanced secretion of triglyceride-rich lipoproteins and (2) impaired clearance of these lipoproteins. The over-secretion of large triglyceride-rich VLDLs from the liver is linked to hepatic steatosis and increased visceral adiposity. The impaired clearance of triglyceride-rich lipoproteins is linked to increased levels of apolipoprotein C-III, a key regulator of triglyceride metabolism. SUMMARY Elucidation of the pathogenesis of the atherogenic dyslipidemia in abdominal obesity combined with the development of novel treatments based on apolipoprotein C-III may in the future lead to better prevention, diagnosis and treatment of the atherogenic dyslipidemia in abdominal obesity.
Collapse
Affiliation(s)
- Elias Björnson
- aDepartment of Molecular and Clinical Medicine, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden bResearch Programs Unit, Diabetes and Obesity, University of Helsinki and Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland
| | | | | | | |
Collapse
|
24
|
Mittendorfer B, Yoshino M, Patterson BW, Klein S. VLDL Triglyceride Kinetics in Lean, Overweight, and Obese Men and Women. J Clin Endocrinol Metab 2016; 101:4151-4160. [PMID: 27588438 PMCID: PMC5095238 DOI: 10.1210/jc.2016-1500] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
CONTEXT High-plasma very low-density lipoprotein (VLDL) triglyceride (TG) concentration and alterations in VLDL-TG metabolism are associated with cardiometabolic disease. OBJECTIVE This study sought to evaluate the interrelationships among factors purported to regulate VLDL-TG metabolism in a large cohort of men and women with a wide range in body adiposity and fat distribution but without diabetes. SUBJECTS AND DESIGN We assessed body composition and fat distribution, plasma insulin concentration, free fatty acid availability, and basal VLDL-TG and VLDL-apoB-100 (VLDL particle number) kinetics in 233 lean, overweight, and obese men and women. RESULTS We found that: 1) plasma VLDL-TG concentration is determined primarily by VLDL-TG secretion rate (SR) in men and by VLDL-TG clearance rate in women; 2) there is a dissociation between VLDL-TG and VLDL-apoB-100 SRs, and VLDL-apoB-100 SR only explains ∼30% of the variance in VLDL-TG SR; 3) ∼50% of people with obesity have high plasma VLDL-TG concentration due to both an increased VLDL-TG SR and a decreased rate of VLDL-TG plasma clearance, and they have lower plasma high-density lipoprotein-cholesterol concentration and more intra-abdominal and liver fat than those with normal VLDL-TG concentration; and 4) fat-free mass, liver fat content and the rate of free fatty acid release into plasma are independent predictors (with a sex × race interaction) of VLDL-TG SR. CONCLUSIONS The regulation of plasma VLDL-TG concentration is complex and influenced by multiple metabolic factors. Many people with obesity have normal plasma VLDL-TG concentrations and kinetics, whereas those with high plasma VLDL-TG concentrations have increased VLDL-TG SR and other markers of cardiometabolic disease risk.
Collapse
Affiliation(s)
- Bettina Mittendorfer
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Mihoko Yoshino
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Bruce W Patterson
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Samuel Klein
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| |
Collapse
|
25
|
Smith GI, Yoshino J, Kelly SC, Reeds DN, Okunade A, Patterson BW, Klein S, Mittendorfer B. High-Protein Intake during Weight Loss Therapy Eliminates the Weight-Loss-Induced Improvement in Insulin Action in Obese Postmenopausal Women. Cell Rep 2016; 17:849-861. [PMID: 27732859 PMCID: PMC5113728 DOI: 10.1016/j.celrep.2016.09.047] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 08/16/2016] [Accepted: 09/15/2016] [Indexed: 01/26/2023] Open
Abstract
High-protein (HP) intake during weight loss (WL) therapy is often recommended because it reduces the loss of lean tissue mass. However, HP intake could have adverse effects on metabolic function, because protein ingestion reduces postprandial insulin sensitivity. In this study, we compared the effects of ∼10% WL with a hypocaloric diet containing 0.8 g protein/kg/day and a hypocaloric diet containing 1.2 g protein/kg/day on muscle insulin action in postmenopausal women with obesity. We found that HP intake reduced the WL-induced decline in lean tissue mass by ∼45%. However, HP intake also prevented the WL-induced improvements in muscle insulin signaling and insulin-stimulated glucose uptake, as well as the WL-induced adaptations in oxidative stress and cell structural biology pathways. Our data demonstrate that the protein content of a WL diet can have profound effects on metabolic function and underscore the importance of considering dietary macronutrient composition during WL therapy for people with obesity.
Collapse
Affiliation(s)
- Gordon I Smith
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jun Yoshino
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Shannon C Kelly
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Dominic N Reeds
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Adewole Okunade
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Bruce W Patterson
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Samuel Klein
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Bettina Mittendorfer
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
| |
Collapse
|
26
|
Maier F, Demmelmair H, Fugmann M, Hellmuth C, Lechner A, Koletzko B, Uhl O. Contribution of glycerophospholipids and sphingomyelin to the circulating NEFA. Prostaglandins Leukot Essent Fatty Acids 2016; 110:55-61. [PMID: 26923087 DOI: 10.1016/j.plefa.2016.01.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 01/13/2016] [Accepted: 01/26/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Serum nonesterified fatty acids (NEFA) are known to be associated with the development of insulin resistance. Recently, differences in the NEFA profile were found in subjects with history of gestational diabetes (postGDM) and healthy controls. Little is known about the NEFA sources in the postprandial state, which prevails most of the day in humans in modern societies. In the present study, we aimed to explore the potential contributions of glycerophospholipid (GPL) and sphingomyelin (SM) fatty acids to the circulating NEFA. METHODS Serum-samples of 19 postGDM women and 20 controls were obtained in fasting state (t0) and 90 minutes (t90) after an oral glucose tolerance test. Fatty acid composition of NEFA and SM were analyzed with liquid chromatography coupled to triple quadrupole mass spectrometry and GPL by gas chromatography. RESULTS The ratio of individual NEFA at t90 vs. t0 (t90/0-ratio) showed no difference between the two groups but increased with chain-length (7% for C16:1, 82% for C26:3). Only NEFA 10:0 was found with lower concentration at t0 and t90 in postGDM. At t90, long-chain polyunsaturated fatty acid correlated closely between NEFA and GPL in postGDM (20:5, 22:4, 22:5 and 22:6) and controls (20:3, 20:4 and 20:5). Very long-chain fatty acid 24:0 correlated significantly between NEFA and SM in postGDM and controls. Saturated and monounsaturated fatty acids correlated less between NEFA and GPL or SM. CONCLUSIONS The NEFA composition varied highly between fasting and fed state in both groups. GPL appeared to contribute long-chain polyunsaturated fatty acid, while SM appeared to contribute very long-chain fatty acids to the NEFA pool.
Collapse
Affiliation(s)
- Felicitas Maier
- Ludwig-Maximilians-University of Munich, Dr. von Hauner Children's Hospital, University of Munich Medical Center, München, Germany
| | - Hans Demmelmair
- Ludwig-Maximilians-University of Munich, Dr. von Hauner Children's Hospital, University of Munich Medical Center, München, Germany
| | - Marina Fugmann
- Ludwig-Maximilians-University of Munich, Diabetes Research Group, Medizinische Klinik und Poliklinik IV, University of Munich Medical Center, Munich, Germany; Clinical Cooperation Group Type 2 Diabetes, Helmholtz Zentrum München, Munich, Germany; German Center for Diabetes Research (DZD), Munich, Germany
| | - Christian Hellmuth
- Ludwig-Maximilians-University of Munich, Dr. von Hauner Children's Hospital, University of Munich Medical Center, München, Germany
| | - Andreas Lechner
- Ludwig-Maximilians-University of Munich, Diabetes Research Group, Medizinische Klinik und Poliklinik IV, University of Munich Medical Center, Munich, Germany; Clinical Cooperation Group Type 2 Diabetes, Helmholtz Zentrum München, Munich, Germany; German Center for Diabetes Research (DZD), Munich, Germany
| | - Berthold Koletzko
- Ludwig-Maximilians-University of Munich, Dr. von Hauner Children's Hospital, University of Munich Medical Center, München, Germany.
| | - Olaf Uhl
- Ludwig-Maximilians-University of Munich, Dr. von Hauner Children's Hospital, University of Munich Medical Center, München, Germany
| |
Collapse
|
27
|
Søndergaard E, Jensen MD. Quantification of adipose tissue insulin sensitivity. J Investig Med 2016; 64:989-91. [PMID: 27073214 DOI: 10.1136/jim-2016-000098] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2016] [Indexed: 11/04/2022]
Abstract
In metabolically healthy humans, adipose tissue is exquisitely sensitive to insulin. Similar to muscle and liver, adipose tissue lipolysis is insulin resistant in adults with central obesity and type 2 diabetes. Perhaps uniquely, however, insulin resistance in adipose tissue may directly contribute to development of insulin resistance in muscle and liver because of the increased delivery of free fatty acids to those tissues. It has been hypothesized that insulin adipose tissue resistance may precede other metabolic defects in obesity and type 2 diabetes. Therefore, precise and reproducible quantification of adipose tissue insulin sensitivity, in vivo, in humans, is an important measure. Unfortunately, no consensus exists on how to determine adipose tissue insulin sensitivity. We review the methods available to quantitate adipose tissue insulin sensitivity and will discuss their strengths and weaknesses.
Collapse
Affiliation(s)
- Esben Søndergaard
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota, USA Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark The Danish Diabetes Academy
| | | |
Collapse
|
28
|
An X, Li L, Chen Y, Luo A, Ni Z, Liu J, Yuan Y, Shi M, Chen B, Long D, Cheng J, Lu Y. Mesenchymal Stem Cells Ameliorated Glucolipotoxicity in HUVECs through TSG-6. Int J Mol Sci 2016; 17:483. [PMID: 27043548 PMCID: PMC4848939 DOI: 10.3390/ijms17040483] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/22/2016] [Accepted: 03/25/2016] [Indexed: 02/05/2023] Open
Abstract
Glucolipotoxicity is one of the critical causal factors of diabetic complications. Whether mesenchymal stem cells (MSCs) have effects on glucolipotoxicity in human umbilical vein endothelial cells (HUVECs) and mechanisms involved are unclear. Thirty mM glucose plus 100 μM palmitic acid was used to induce glucolipotoxicity in HUVECs. MSCs and HUVECs were co-cultured at the ratio of 1:5 via Transwell system. The mRNA expressions of inflammatory factors were detected by RT-qPCR. The productions of reactive oxygen species (ROS), cell cycle and apoptosis were analyzed by flow cytometry. The tumor necrosis factor-α stimulated protein 6 (TSG-6) was knockdown in MSCs by RNA interference. High glucose and palmitic acid remarkably impaired cell viability and tube formation capacity, as well as increased the mRNA expression of inflammatory factors, ROS levels, and cell apoptosis in HUVECs. MSC co-cultivation ameliorated these detrimental effects in HUVECs, but no effect on ROS production. Moreover, TSG-6 was dramatically up-regulated by high glucose and fatty acid stimulation in both MSCs and HUVECs. TSG-6 knockdown partially abolished the protection mediated by MSCs. MSCs had protective effects on high glucose and palmitic acid induced glucolipotoxicity in HUVECs, and TSG-6 secreted by MSCs was likely to play an important role in this process.
Collapse
Affiliation(s)
- Xingxing An
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health; West China Hospital, Sichuan University, Chengdu 610041, China.
| | - Lan Li
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health; West China Hospital, Sichuan University, Chengdu 610041, China.
| | - Younan Chen
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health; West China Hospital, Sichuan University, Chengdu 610041, China.
- School of Biomedical Sciences, CHIRI Biosciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
| | - Ai Luo
- Sichuan Neo-Life Stem Cell Biotech Inc. Chengdu 610041, China.
| | - Zuyao Ni
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada.
| | - Jingping Liu
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health; West China Hospital, Sichuan University, Chengdu 610041, China.
| | - Yujia Yuan
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health; West China Hospital, Sichuan University, Chengdu 610041, China.
| | - Meimei Shi
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health; West China Hospital, Sichuan University, Chengdu 610041, China.
| | - Bo Chen
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health; West China Hospital, Sichuan University, Chengdu 610041, China.
| | - Dan Long
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health; West China Hospital, Sichuan University, Chengdu 610041, China.
| | - Jingqiu Cheng
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health; West China Hospital, Sichuan University, Chengdu 610041, China.
| | - Yanrong Lu
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health; West China Hospital, Sichuan University, Chengdu 610041, China.
| |
Collapse
|
29
|
Umpleby AM. HORMONE MEASUREMENT GUIDELINES: Tracing lipid metabolism: the value of stable isotopes. J Endocrinol 2015; 226:G1-10. [PMID: 26047888 DOI: 10.1530/joe-14-0610] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/04/2015] [Indexed: 01/14/2023]
Abstract
Labelling molecules with stable isotopes to create tracers has become a gold-standard method to study the metabolism of lipids and lipoproteins in humans. There are a range of techniques which use stable isotopes to measure fatty acid flux and oxidation, hepatic fatty synthesis, cholesterol absorption and synthesis and lipoprotein metabolism in humans. Stable isotope tracers are safe to use, enabling repeated studies to be undertaken and allowing studies to be undertaken in children and pregnant women. This review provides details of the most appropriate tracers to use, the techniques which have been developed and validated for measuring different aspects of lipid metabolism and some of the limitations of the methodology.
Collapse
Affiliation(s)
- A Margot Umpleby
- Diabetes and Metabolic MedicineFaculty of Health and Metabolic Sciences, University of Surrey, Leggett Building, Daphne Jackson Road, Manor Park, Guildford GU2 7WG, UK
| |
Collapse
|
30
|
Hamada Y, Nagasaki H, Fujiya A, Seino Y, Shang QL, Suzuki T, Hashimoto H, Oiso Y. Involvement of de novo ceramide synthesis in pro-inflammatory adipokine secretion and adipocyte–macrophage interaction. J Nutr Biochem 2014; 25:1309-16. [DOI: 10.1016/j.jnutbio.2014.07.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 05/14/2014] [Accepted: 07/24/2014] [Indexed: 01/28/2023]
|
31
|
Macfarlane DP, Raubenheimer PJ, Preston T, Gray CD, Bastin ME, Marshall I, Iredale JP, Andrew R, Walker BR. Effects of acute glucocorticoid blockade on metabolic dysfunction in patients with Type 2 diabetes with and without fatty liver. Am J Physiol Gastrointest Liver Physiol 2014; 307:G760-8. [PMID: 25104497 PMCID: PMC4187063 DOI: 10.1152/ajpgi.00030.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To investigate the potential of therapies which reduce glucocorticoid action in patients with Type 2 diabetes we performed a randomized, double-blinded, placebo-controlled crossover study of acute glucocorticoid blockade, using the glucocorticoid receptor antagonist RU38486 (mifepristone) and cortisol biosynthesis inhibitor (metyrapone), in 14 men with Type 2 diabetes. Stable isotope dilution methodologies were used to measure the rates of appearance of glucose, glycerol, and free fatty acids (FFAs), including during a low-dose (10 mU·m⁻² ·min⁻¹) hyperinsulinemic clamp, and subgroup analysis was conducted in patients with high or low liver fat content measured by magnetic resonance spectroscopy (n = 7/group). Glucocorticoid blockade lowered fasting glucose and insulin levels and improved insulin sensitivity of FFA and glycerol turnover and hepatic glucose production. Among this population with Type 2 diabetes high liver fat was associated with hyperinsulinemia, higher fasting glucose levels, peripheral and hepatic insulin resistance, and impaired suppression of FFA oxidation and FFA and glycerol turnover during hyperinsulinemia. Glucocorticoid blockade had similar effects in those with and without high liver fat. Longer term treatments targeting glucocorticoid action may be useful in Type 2 diabetes with and without fatty liver.
Collapse
Affiliation(s)
- D. P. Macfarlane
- 1University/BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, Scotland, United Kingdom;
| | - P. J. Raubenheimer
- 1University/BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, Scotland, United Kingdom;
| | - T. Preston
- 2Scottish Universities Environmental Research Centre, University of Glasgow, Glasgow, Scotland, United Kingdom;
| | - C. D. Gray
- 3SFC Brain Imaging Research Centre, University of Edinburgh, Edinburgh, Scotland, United Kingdom; and
| | - M. E. Bastin
- 3SFC Brain Imaging Research Centre, University of Edinburgh, Edinburgh, Scotland, United Kingdom; and
| | - I. Marshall
- 3SFC Brain Imaging Research Centre, University of Edinburgh, Edinburgh, Scotland, United Kingdom; and
| | - J. P. Iredale
- 4University/MRC Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - R. Andrew
- 1University/BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, Scotland, United Kingdom;
| | - B. R. Walker
- 1University/BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, Scotland, United Kingdom;
| |
Collapse
|
32
|
Yoshino J, Almeda-Valdes P, Patterson BW, Okunade AL, Imai SI, Mittendorfer B, Klein S. Diurnal variation in insulin sensitivity of glucose metabolism is associated with diurnal variations in whole-body and cellular fatty acid metabolism in metabolically normal women. J Clin Endocrinol Metab 2014; 99:E1666-70. [PMID: 24878055 PMCID: PMC4154096 DOI: 10.1210/jc.2014-1579] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 05/19/2014] [Indexed: 12/13/2022]
Abstract
CONTEXT The mechanism(s) responsible for diurnal variations in insulin sensitivity of glucose metabolism in healthy people are unclear. OBJECTIVE The objective of the study was to evaluate whether diurnal variations in whole-body and cellular fatty acid metabolism could contribute to evening insulin resistance in metabolically normal people. SUBJECTS AND DESIGN We measured plasma the free fatty acid (FFA) concentration, palmitate kinetics, and skeletal muscle expression of genes involved in fatty acid metabolism at breakfast (7:00 am) and dinner (7:00 pm) in 13 overweight (body mass index 27.8 ± 1.2 kg/m(2)) but metabolically normal, women. RESULTS Plasma FFA concentration was approximately 30% greater just before consuming dinner than breakfast (P < .05) and remained greater after dinner than breakfast (FFA areas under the curve: 0.88 ± 0.33 and 0.51 ± 0.09 μmol/mL × 4 h, P = .001). However, adipose tissue lipolytic activity was not different in the evening and in the morning. Skeletal muscle expression of genes that regulate fatty acid oxidation were 38-82% lower, whereas genes involved in de novo lipogenesis were 51%-87 % higher before dinner than before breakfast (all P < .05), and these changes were associated with diurnal variation in the muscle expression of core clock genes that regulate fatty acid metabolism. CONCLUSION Metabolically normal women demonstrate diurnal variations in fatty acid metabolism, manifested by an increase in circulating FFAs, presumably derived from previous meal consumption rather than lipolysis of adipose tissue triglycerides, and a shift in muscle fatty acid metabolism from oxidation to lipogenesis. These metabolic alterations could be responsible for the known evening decline in insulin sensitivity.
Collapse
Affiliation(s)
- Jun Yoshino
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine (J.Y., P.A.-V., B.W.P., A.L.O., S.I., B.M., S.K.) and Department of Developmental Biology (S.I.), Washington University School of Medicine, St Louis, Missouri 63110
| | | | | | | | | | | | | |
Collapse
|
33
|
Smith GI, Reeds DN, Okunade AL, Patterson BW, Mittendorfer B. Systemic delivery of estradiol, but not testosterone or progesterone, alters very low density lipoprotein-triglyceride kinetics in postmenopausal women. J Clin Endocrinol Metab 2014; 99:E1306-10. [PMID: 24694337 PMCID: PMC4079308 DOI: 10.1210/jc.2013-4470] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Sexual dimorphism in plasma triglyceride (TG) metabolism is well established but it is unclear to what extent it is driven by differences in the sex hormone milieu. RESULTS from previous studies evaluating the effects of sex steroids on plasma TG homeostasis are inconclusive because they relied on orally administered synthetic hormone preparations or evaluated only plasma lipid concentrations but not kinetics. OBJECTIVE The purpose of this study was to evaluate the effects of systemically delivered 17β-estradiol, progesterone, and T on very low density lipoprotein-triglyceride (VLDL-TG) concentration and kinetics in postmenopausal women. SETTING AND DESIGN VLDL-TG concentration and kinetics were evaluated by using stable isotope-labeled tracer techniques in four groups of postmenopausal women (n = 27 total) who were studied before and after treatment with either 17β-estradiol (0.1 mg/d via continuous delivery skin patch), progesterone (100 mg/d via vaginal insert) and T (12.5 mg/d via skin gel), or no intervention (control group). RESULTS VLDL-TG concentration and kinetics were unchanged in the control group and not altered by T and progesterone administration. Estradiol treatment, in contrast, reduced VLDL-TG concentration by approximately 30% due to accelerated VLDL-TG plasma clearance (25.1 ± 2.5 vs. 17.4 ± 2.7 mL/min; P < .01). CONCLUSIONS Estradiol, but not progesterone or T, is a major regulator of VLDL-TG metabolism.
Collapse
Affiliation(s)
- Gordon I Smith
- Washington University School of Medicine, St Louis, Missouri 63110
| | | | | | | | | |
Collapse
|
34
|
Rogers C, Davis B, Neufer PD, Murphy MP, Anderson EJ, Robidoux J. A transient increase in lipid peroxidation primes preadipocytes for delayed mitochondrial inner membrane permeabilization and ATP depletion during prolonged exposure to fatty acids. Free Radic Biol Med 2014; 67:330-41. [PMID: 24269897 PMCID: PMC3935619 DOI: 10.1016/j.freeradbiomed.2013.11.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 10/29/2013] [Accepted: 11/12/2013] [Indexed: 12/22/2022]
Abstract
Preadipocytes are periodically subjected to fatty acid (FA) concentrations that are potentially cytotoxic. We tested the hypothesis that prolonged exposure of preadipocytes of human origin to a physiologically relevant mix of FAs leads to mitochondrial inner membrane (MIM) permeabilization and ultimately to mitochondrial crisis. We found that exposure of preadipocytes to FAs led to progressive cyclosporin A-sensitive MIM permeabilization, which in turn caused a reduction in MIM potential, oxygen consumption, and ATP synthetic capacity and, ultimately, death. Additionally, we showed that FAs induce a transient increase in intramitochondrial reactive oxygen species (ROS) and lipid peroxide production, lasting roughly 30 and 120min for the ROS and lipid peroxides, respectively. MIM permeabilization and its deleterious consequences including mitochondrial crisis and cell death were prevented by treating the cells with the mitochondrial FA uptake inhibitor etomoxir, the mitochondrion-selective superoxide and lipid peroxide antioxidants MitoTempo and MitoQ, or the lipid peroxide and reactive carbonyl scavenger l-carnosine. FAs also promoted a delayed oxidative stress phase. However, the beneficial effects of etomoxir, MitoTempo, and l-carnosine were lost by delaying the treatment by 2h, suggesting that the initial phase was sufficient to prime the cells for the delayed MIM permeabilization and mitochondrial crisis. It also suggested that the second ROS production phase is a consequence of this loss in mitochondrial health. Altogether, our data suggest that approaches designed to diminish intramitochondrial ROS or lipid peroxide accumulation, as well as MIM permeabilization, are valid mechanism-based therapeutic avenues to prevent the loss in preadipocyte metabolic fitness associated with prolonged exposure to elevated FA levels.
Collapse
Affiliation(s)
- Carlyle Rogers
- Department of Pharmacology and Toxicology, East Carolina University, Greenville, NC 27834, USA
| | - Barbara Davis
- Department of Pharmacology and Toxicology, East Carolina University, Greenville, NC 27834, USA
| | - P Darrell Neufer
- Department of Physiology, East Carolina University, Greenville, NC 27834, USA; Department of Kinesiology, East Carolina University, Greenville, NC 27834, USA; East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834, USA
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Cambridge CB2 0XY, UK
| | - Ethan J Anderson
- Department of Pharmacology and Toxicology, East Carolina University, Greenville, NC 27834, USA; Department of Kinesiology, East Carolina University, Greenville, NC 27834, USA; East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834, USA
| | - Jacques Robidoux
- Department of Pharmacology and Toxicology, East Carolina University, Greenville, NC 27834, USA; East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834, USA.
| |
Collapse
|
35
|
Association between plasma nonesterified fatty acids species and adipose tissue fatty acid composition. PLoS One 2013; 8:e74927. [PMID: 24098359 PMCID: PMC3788793 DOI: 10.1371/journal.pone.0074927] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 08/06/2013] [Indexed: 12/18/2022] Open
Abstract
Fatty acid composition of adipose tissue (AT) is an established long-term biomarker for fatty acid (FA) intake and status, but AT samples are not easily available. Nonesterified FA composition in plasma (pNEFA) may be a good indicator of AT FA composition, because pNEFA are mainly generated by AT lipolysis. We investigated the correlation of 42 pNEFA and subcutaneous as well as visceral AT FA in 27 non-diabetic women with a median BMI of 36 kg/m2 (Q0.25: 25 kg/m2; Q0.75: 49 kg/m2). Close correlations of pNEFA and AT FA were found for odd-chain FA (15∶0 r = 0.838 and 0.862 for subcutaneous and visceral AT, respectively) and omega-3 FA (22∶6 r = 0.719/0.535), while no significant or low correlations were found for other FA including 18∶1 (r = 0.384/0.325) and 20∶4 (r = 0.386/0.266). Close correlations of pNEFA and AT FA were found for essential fatty acids, like 18∶2 (r = 0.541/0.610) and 20∶5 (r = 0.561/0.543). The lower correlation for some pNEFA species with AT FA indicates that the variation of most pNEFA is significantly affected by other FA sources and flux of FA to tissue, in addition to release from AT. A relevant influence of BMI on the level of correlation was shown for saturated FA. NEFA analysis in fasted plasma can serve as a virtual AT biopsy for some FA, and as a biomarker for intake of dairy products and sea fish.
Collapse
|
36
|
Godin JP, Ross AB, Cléroux M, Pouteau E, Montoliu I, Moser M, Kochhar S. Natural carbon isotope abundance of plasma metabolites and liver tissue differs between diabetic and non-diabetic Zucker diabetic fatty rats. PLoS One 2013; 8:e74866. [PMID: 24086387 PMCID: PMC3781116 DOI: 10.1371/journal.pone.0074866] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 08/07/2013] [Indexed: 01/11/2023] Open
Abstract
Background ‘You are what you eat’ is an accurate summary for humans and animals when it comes to carbon isotope abundance. In biological material, natural13C/12C ratio is subject to minute variations due to diet composition (mainly from ingestion of C3 and C4 metabolism plants) and to the discrimination between ‘light’ and ‘heavy’ isotopes during biochemical reactions (isotope effects and isotopic fractionation). Methodology/Principal Findings Carbon isotopic abundance was measured in ZDF (fa/+) and ZDF (fa/fa), (lean and obese-diabetic rats respectively) fed the same diet. By analysing plasma metabolites (glucose and non-esterified fatty acids), breath and liver tissue by high-precision isotope ratio mass spectrometry, we demonstrate for the first time statistically distinguishable metabolic carbon isotope abundance between ZDF (fa/+) and ZDF (fa/fa) rats based on plasma glucose, palmitic, oleic, linoleic, arachidonic acids and bulk analysis of liver tissue (P<0.005) resulting into clear isotopic fingerprints using principal component analysis. We studied the variation of isotopic abundance between both groups for each metabolite and through the metabolic pathways using the precursor/product approach. We confirmed that lipids were depleted in 13C compared to glucose in both genotypes. We found that isotopic abundance of linoleic acid (C18: 2n-6), even though both groups had the same feed, differed significantly between both groups. The likely reason for these changes between ZDF (fa/+) and ZDF (fa/fa) are metabolic dysregulation associated with various routing and fluxes of metabolites. Conclusion/Significance This work provides evidence that measurement of natural abundance isotope ratio of both bulk tissue and individual metabolites can provide meaningful information about metabolic changes either associated to phenotype or to genetic effects; irrespective of concentration. In the future measuring the natural abundance δ13C of key metabolites could be used as endpoints for studying in vivo metabolism, especially with regards to metabolic dysregulation, and development and progression of metabolic diseases.
Collapse
Affiliation(s)
| | - Alastair B. Ross
- Analytical Sciences, Nestlé Research Center, Lausanne, Switzerland
| | - Marilyn Cléroux
- Analytical Sciences, Nestlé Research Center, Lausanne, Switzerland
| | - Etienne Pouteau
- Analytical Sciences, Nestlé Research Center, Lausanne, Switzerland
| | - Ivan Montoliu
- Analytical Sciences, Nestlé Research Center, Lausanne, Switzerland
| | - Mireille Moser
- Analytical Sciences, Nestlé Research Center, Lausanne, Switzerland
| | - Sunil Kochhar
- Analytical Sciences, Nestlé Research Center, Lausanne, Switzerland
| |
Collapse
|
37
|
Newsom SA, Everett AC, Hinko A, Horowitz JF. A single session of low-intensity exercise is sufficient to enhance insulin sensitivity into the next day in obese adults. Diabetes Care 2013; 36:2516-22. [PMID: 23757424 PMCID: PMC3747878 DOI: 10.2337/dc12-2606] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The purpose of this study was to determine the effect of a relatively modest session of exercise on insulin sensitivity and fatty acid uptake the next day in obese adults. RESEARCH DESIGN AND METHODS Eleven sedentary obese adults (male/female: 3/8; BMI 37 ± 1 kg/m(2); peak oxygen uptake [VO2peak] 20 ± 1 mL/kg/min) completed three experimental trials. On two of these occasions, subjects exercised to expend 350 kcal in the afternoon. These two exercise trials were identical except for the exercise intensity (50% VO2peak [EX50] and 65% VO2peak [EX65]) and the duration of exercise necessary to expend 350 kcal (EX50 = ≈ 70 min; EX65 = ≈ 55 min). Subjects also completed a control trial (CON), without exercise. The next morning, we measured insulin sensitivity (hyperinsulinemic-euglycemic clamp) and whole-body fatty acid uptake (palmitate rate of disappearance from plasma [Rd]). RESULTS Exercise increased insulin sensitivity the next day, but whereas the 35% improvement after EX50 compared with CON was statistically significant (P = 0.01), the 20% improvement after EX65 was not (P = 0.17). Despite nearly identical values between CON and EX65 (P = 0.88), systemic fatty acid uptake was lower after EX50 compared with EX65 (P = 0.02), but not quite significant compared with CON (P = 0.07). Importantly, the change in fatty acid uptake after exercise compared with CON was negatively correlated with the change in insulin sensitivity for all trials (r = -0.60, P = 0.003). CONCLUSIONS A relatively modest single session of exercise in obese adults improved insulin sensitivity the next day, and a reduction in systemic fatty acid uptake in the several hours after exercise may be important for this effect.
Collapse
Affiliation(s)
- Sean A Newsom
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, USA
| | | | | | | |
Collapse
|
38
|
Chai JT, Choudhury RP. Cardiometabolic interventions - focus on transcriptional regulators. THE EUROPEAN JOURNAL OF CARDIOVASCULAR MEDICINE 2013; 2:212-218. [PMID: 24040490 PMCID: PMC3769682 DOI: 10.5083/ejcm.20424884.102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cardiovascular disease (CVD) remains the largest healthcare burden in the Western world; and the increasing prevalence of type II diabetes mellitus, at least partially driven by a trend in lifestyle changes associated with global economic development, is likely to fuel this CVD burden worldwide. Over the past two decades, there has been an increased awareness of the convergence of risk factors contributing to both cardiovascular disease and diabetes leading to the concept of the metabolic syndrome, and the realisation of the opportunity to intervene at this intersection to simultaneously target CVD and metabolic dysfunction. This brings together the fields of cardiovascular medicine, diabetology, and increasingly clinical immunology for a unified and concerted effort to reduce risk for both conditions simultaneously. The discovery of the targeted pathways of drugs already in clinical use such as fibrates and thiazolidinediones (TZD) has led to accelerated basic and clinical research into selective and dual PPAR-α and PPAR-γ agonists, which can theoretically target glucose, lipid and lipoprotein metabolism, as well as potentially exerting inhibitoryeffects in vascular inflammation, all of which might be predicted to reduce atherosclerosis. In this article, we will discuss the basic science as well as recent clinical development in the pursuit of optimal cardiometabolic intervention along with insight into strategies for future drug development.
Collapse
Affiliation(s)
- Joshua T Chai
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine University of Oxford, United Kingdom
| | | |
Collapse
|
39
|
Smith GI, Magkos F, Reeds DN, Okunade AL, Patterson BW, Mittendorfer B. One day of mixed meal overfeeding reduces hepatic insulin sensitivity and increases VLDL particle but not VLDL-triglyceride secretion in overweight and obese men. J Clin Endocrinol Metab 2013; 98:3454-62. [PMID: 23750033 PMCID: PMC3733854 DOI: 10.1210/jc.2013-1786] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT The exact mechanisms responsible for increased plasma triglyceride (TG) concentration in obese people are unclear, and it is not known whether excess energy intake per se is involved in the pathophysiology of this abnormality. OBJECTIVE The purpose of our study was to examine how excess energy intake from a balanced diet for 1 day affects very-low-density lipoprotein (VLDL)-TG kinetics and its putative regulators hepatic insulin sensitivity and plasma free fatty acid availability. SUBJECTS AND DESIGN We used stable isotope-labeled tracer methods to evaluate glucose and lipid kinetics in 8 overweight and obese men (age, 38 ± 3 years; body mass index, 33.7 ± 1.7 kg/m(2); means ± SEM) on 2 occasions (randomized crossover design): once, the day after they consumed a balanced diet that provided an amount of energy that matched their energy expenditure, and another time, the day after they consumed a balanced diet that provided 30% excess calories. Eight healthy, lean men (34 ± 1 years; 22.5 ± 0.6 kg/m(2)) were studied under isocaloric conditions only to provide a reference for normal lipid kinetics. RESULTS VLDL-TG and VLDL-apolipoprotein B-100 (apoB-100) concentrations and secretion rates were significantly greater (P < .01) in overweight/obese compared with lean men. Hypercaloric, compared with isocaloric, feeding in overweight/obese men increased glucose rate of appearance in plasma (904 ± 21 vs 873 ± 26 μmol/min), the hepatic insulin resistance index (10.9 ± 2.2 vs 8.3 ± 1.8), and VLDL-apoB-100 concentration and secretion rate (1.91 ± 0.24 vs. 1.53 ± 0.13 nmol/min), whereas VLDL-apoB-100 plasma clearance rate, VLDL-TG secretion and plasma clearance rates, and free fatty acid rate of appearance in plasma were not affected by overfeeding. CONCLUSION One day of moderate overfeeding (30% excess energy intake) stimulates hepatic glucose and VLDL-apo B-100 secretion rates but has no effect on hepatic and adipose tissue fatty acid metabolism in overweight/obese men.
Collapse
Affiliation(s)
- Gordon I Smith
- Washington University School of Medicine, St Louis, Missouri 63110, USA
| | | | | | | | | | | |
Collapse
|
40
|
Previs SF, McLaren DG, Wang SP, Stout SJ, Zhou H, Herath K, Shah V, Miller PL, Wilsie L, Castro-Perez J, Johns DG, Cleary MA, Roddy TP. New methodologies for studying lipid synthesis and turnover: looking backwards to enable moving forwards. Biochim Biophys Acta Mol Basis Dis 2013; 1842:402-13. [PMID: 23707557 DOI: 10.1016/j.bbadis.2013.05.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 05/11/2013] [Accepted: 05/13/2013] [Indexed: 12/26/2022]
Abstract
Our ability to understand the pathogenesis of problems surrounding lipid accretion requires attention towards quantifying lipid kinetics. In addition, studies of metabolic flux should also help unravel mechanisms that lead to imbalances in inter-organ lipid trafficking which contribute to dyslipidemia and/or peripheral lipid accumulation (e.g. hepatic fat deposits). This review aims to outline the development and use of novel methods for studying lipid kinetics in vivo. Although our focus is directed towards some of the approaches that are currently reported in the literature, we include a discussion of the older literature in order to put "new" methods in better perspective and inform readers of valuable historical research. Presumably, future advances in understanding lipid dynamics will benefit from a careful consideration of the past efforts, where possible we have tried to identify seminal papers or those that provide clear data to emphasize essential points. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.
Collapse
Affiliation(s)
- Stephen F Previs
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA.
| | - David G McLaren
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Sheng-Ping Wang
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Steven J Stout
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Haihong Zhou
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Kithsiri Herath
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Vinit Shah
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Paul L Miller
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Larissa Wilsie
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Jose Castro-Perez
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Douglas G Johns
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Michele A Cleary
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Thomas P Roddy
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| |
Collapse
|
41
|
Nelson RH, Mundi MS, Vlazny DT, Smailovic A, Muthusamy K, Almandoz JP, Singh E, Jensen MD, Miles JM. Kinetics of saturated, monounsaturated, and polyunsaturated fatty acids in humans. Diabetes 2013; 62:783-8. [PMID: 23274886 PMCID: PMC3581192 DOI: 10.2337/db12-0367] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Plasma free fatty acid (FFA) kinetics in humans are often measured with only one tracer. In study 1, healthy volunteers received infusions of [U-¹³C]linoleate, [U-¹³C]oleate, and [U-¹³C]palmitate during continuous feeding with liquid meals low (n = 12) and high (n = 5) in palmitate and containing three labeled fatty acids to measure FFA appearance and fractional spillover of lipoprotein lipase-generated fatty acids. Study 2 used an intravenous lipid emulsion to increase FFA concentrations during infusion of linoleate and palmitate tracers. In study 1, there were no differences in spillover of the three fatty acids for the low-palmitate meal, but linoleate spillover was greater than oleate or palmitate for the high-palmitate meal. In studies 1 and 2, clearance was significantly greater for linoleate than for the other FFAs. There was a negative correlation between clearance and concentration for each fatty acid in the two studies. In study 1, concentration and spillover correlated positively for oleate and palmitate but negatively for linoleate. In conclusion, linoleate spillover is greater than that of other fatty acids under some circumstances. Linoleate clearance is greater than that of palmitate or oleate, indicating a need for caution when using a single FFA to infer the behavior of all fatty acids.
Collapse
Affiliation(s)
- Robert H Nelson
- Endocrine Research Unit, Division of Endocrinology, Metabolism, Diabetes, and Nutrition, Mayo Clinic, Rochester, Minnesota, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Miller BV, Patterson BW, Okunade A, Klein S. Fatty acid and very low density lipoprotein metabolism in obese African American and Caucasian women with type 2 diabetes. J Lipid Res 2012; 53:2767-72. [PMID: 23048205 DOI: 10.1194/jlr.p030593] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) is associated with increased plasma triglyceride (TG) concentrations, but African Americans (AA) have lower plasma TG than Caucasians (CC). We evaluated the hypothesis that obese AA women have lower plasma TG than obese CC women do because of differences in lipid kinetics. Eleven AA and 11 CC obese women with T2DM, matched on body mass index (BMI) (AA = 37 ± 1, CC = 37 ± 1 kg/m(2)), age, duration of diabetes, percentage body fat, and insulin sensitivity (S(I), determined by an intravenous glucose tolerance test), were studied. Plasma TG concentration (AA = 1.14 ± 0.11, CC = 1.88 ± 0.18 mmol/l), FFA rate of appearance (R(a)) into plasma (AA = 419 ± 27, CC = 503 ± 31 µmol·min(-1)), and total VLDL-TG secretion rate (AA = 18 ± 2, CC = 29 ± 4 µmol·min(-1)) were lower in AA than CC women (all P < 0.05). In contrast, plasma total apolipoprotein (apo)B-100 concentration (AA = 1,542 ± 179, CC = 1,620 ± 118 nmol/l) and VLDL-apoB-100 secretion rate (AA = 1.3 ± 0.1, CC = 1.3 ± 0.1 nmol·min(-1)) were similar in both groups, so the molar ratio of VLDL-TG secretion rate to VLDL-apoB-100 secretion rate was lower in AA women than in CC women. VLDL-TG concentration was lower in AA women due to lower total VLDL-TG secretion rate. However, the VLDL-apoB-100 secretion rate was the same in both groups, demonstrating that AA women secrete smaller VLDL particles containing less TG than do CC women.
Collapse
Affiliation(s)
- Bernard V Miller
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | | | | | | |
Collapse
|
43
|
Wang X, Magkos F, Patterson BW, Reeds DN, Kampelman J, Mittendorfer B. Low-dose dexamethasone administration for 3 weeks favorably affects plasma HDL concentration and composition but does not affect very low-density lipoprotein kinetics. Eur J Endocrinol 2012; 167:217-23. [PMID: 22619349 PMCID: PMC3638974 DOI: 10.1530/eje-12-0180] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Subclinical hypercortisolemia often occurs in subjects with features of the metabolic syndrome, and it has been suggested that it may be, at least in part, responsible for the development of these metabolic abnormalities. However, the metabolic effects of glucocorticoid administration to mimic subclinical glucocorticoid excess have not been evaluated. METHODS We used stable isotope-labeled tracer methods in conjunction with magnetic resonance techniques to measure the effect of glucocorticoid excess within the physiological range (~0.7 mg dexamethasone/day for 3 weeks) on glucose and free fatty acid (FFA) rates of appearance (Ra) into plasma, intrahepatic triglyceride (TG) content, very low-density lipoprotein (VLDL)-TG and VLDL-apolipoprotein B-100 (apoB-100) kinetics and plasma lipoprotein subclass concentrations, and particle sizes in nine overweight and obese individuals. RESULTS Dexamethasone treatment led to a very small but significant increase in body weight (from 87.4±7.1 to 88.6±7.2 kg; P=0.003) and increased HDL-cholesterol (from 45.9±2.8 to 55.1±4.6 mg/dl; P=0.037) and HDL particle (from 33.7±2.2 to 41.4±4.2 nmol/l; P=0.023) concentrations in plasma but had no effect on intrahepatic TG content, glucose and FFA Ra in plasma, hepatic VLDL-TG and VLDL-apoB-100 secretion rates and mean residence times in the circulation, plasma TG and LDL-cholesterol concentrations, and plasma lipoprotein particle sizes. CONCLUSION Subclinical hypercortisolemia does not have significant adverse metabolic consequences.
Collapse
Affiliation(s)
- Xuewen Wang
- Division of Geriatrics and Nutritional Science, Washington University School of Medicine, Center for Human Nutrition, St Louis, Missouri 63110, USA
| | | | | | | | | | | |
Collapse
|
44
|
Ramos-Roman MA, Lapidot SA, Phair RD, Parks EJ. Insulin activation of plasma nonesterified fatty acid uptake in metabolic syndrome. Arterioscler Thromb Vasc Biol 2012; 32:1799-808. [PMID: 22723441 DOI: 10.1161/atvbaha.112.250019] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Insulin control of fatty acid metabolism has long been deemed dominated by suppression of adipose lipolysis. The goal of the present study was to test the hypothesis that this single role of insulin is insufficient to explain observed fatty acid dynamics. METHODS AND RESULTS Fatty acid kinetics were measured during a meal tolerance test and insulin sensitivity assessed by intravenous glucose tolerance test in overweight human subjects (n=15; body mass index, 35.8 ± 7.1 kg/m(2)). Non-steady state tracer kinetic models were formulated and tested using ProcessDB software. Suppression of adipose fatty acid release, by itself, could not account for postprandial nonesterified fatty acid concentration changes, but adipose suppression combined with insulin activation of fatty acid uptake was consistent with the measured data. The observed insulin K(m) for nonesterified fatty acid uptake was inversely correlated with both insulin sensitivity of glucose uptake (intravenous glucose tolerance test insulin sensitivity; r=-0.626; P=0.01) and whole body fat oxidation after the meal (r=-0.538; P=0.05). CONCLUSIONS These results support insulin regulation of fatty acid turnover by both release and uptake mechanisms. Activation of fatty acid uptake is consistent with the human data, has mechanistic precedent in cell culture, and highlights a new potential target for therapies aimed at improving the control of fatty acid metabolism in insulin-resistant disease states.
Collapse
Affiliation(s)
- Maria A Ramos-Roman
- Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX 75390-9052, USA
| | | | | | | |
Collapse
|
45
|
Sullivan S, Kirk EP, Mittendorfer B, Patterson BW, Klein S. Randomized trial of exercise effect on intrahepatic triglyceride content and lipid kinetics in nonalcoholic fatty liver disease. Hepatology 2012; 55:1738-45. [PMID: 22213436 PMCID: PMC3337888 DOI: 10.1002/hep.25548] [Citation(s) in RCA: 201] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 12/10/2011] [Indexed: 12/13/2022]
Abstract
UNLABELLED Nonalcoholic fatty liver disease (NAFLD) and alterations in hepatic lipoprotein kinetics are common metabolic complications associated with obesity. Lifestyle modification involving diet-induced weight loss and regular exercise decreases intrahepatic triglyceride (IHTG) content and very low density lipoprotein (VLDL) triglyceride (TG) secretion rate. The aim of this study was to evaluate the weight loss-independent effect of following the physical activity guidelines recommended by the Department of Health and Human Services on IHTG content and VLDL kinetics in obese persons with NAFLD. Eighteen obese people (body mass index [BMI]: 38.1 ± 4.6 kg/m(2)) with NAFLD were randomized to 16 weeks of exercise training (45%-55% VO(2peak) , 30-60 minutes × 5 days/week; n = 12) or observation (control; n = 6). Magnetic resonance spectroscopy and stable isotope tracer infusions in conjunction with compartmental modeling were used to evaluate IHTG content and hepatic VLDL-TG and apolipoprotein B-100 (apoB-100) secretion rates. Exercise training resulted in a 10.3% ± 4.6% decrease in IHTG content (P < 0.05), but did not change total body weight (103.1 ± 4.2 kg before and 102.9 ± 4.2 kg after training) or percent body fat (38.9% ± 2.1% before and 39.2% ± 2.1% after training). Exercise training did not change the hepatic VLDL-TG secretion rate (17.7 ± 3.9 μmol/min before and 16.8 ± 5.4 μmol/min after training) or VLDL-apoB-100 secretion rate (1.5 ± 0.5 nmol/min before and 1.6 ± 0.6 nmol/min after training). CONCLUSION Following the Department of Health and Human Services recommended physical activity guidelines has small but beneficial effects on IHTG content, but does not improve hepatic lipoprotein kinetics in obese persons with NAFLD.
Collapse
Affiliation(s)
- Shelby Sullivan
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
,Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA
,Division of Gastroenterology, Washington University School of Medicine, St. Louis, MO, USA
| | - Erik P. Kirk
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
,Department of Kinesiology and Health Education, Southern Illinois University, Edwardsville, IL, USA
| | - Bettina Mittendorfer
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
,Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Bruce W. Patterson
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
,Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Samuel Klein
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
,Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA
| |
Collapse
|
46
|
Conte C, Fabbrini E, Kars M, Mittendorfer B, Patterson BW, Klein S. Multiorgan insulin sensitivity in lean and obese subjects. Diabetes Care 2012; 35:1316-21. [PMID: 22474039 PMCID: PMC3357234 DOI: 10.2337/dc11-1951] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To provide a comprehensive assessment of multiorgan insulin sensitivity in lean and obese subjects with normal glucose tolerance. RESEARCH DESIGN AND METHODS The hyperinsulinemic-euglycemic clamp procedure with stable isotopically labeled tracer infusions was performed in 40 obese (BMI 36.2 ± 0.6 kg/m(2), mean ± SEM) and 26 lean (22.5 ± 0.3 kg/m(2)) subjects with normal glucose tolerance. Insulin was infused at different rates to achieve low, medium, and high physiological plasma concentrations. RESULTS In obese subjects, palmitate and glucose R(a) in plasma decreased with increasing plasma insulin concentrations. The decrease in endogenous glucose R(a) was greater during low-, medium-, and high-dose insulin infusions (69 ± 2, 74 ± 2, and 90 ± 2%) than the suppression of palmitate R(a) (52 ± 4, 68 ± 1, and 79 ± 1%). Insulin-mediated increase in glucose disposal ranged from 24 ± 5% at low to 253 ± 19% at high physiological insulin concentrations. The suppression of palmitate R(a) and glucose R(a) were greater in lean than obese subjects during low-dose insulin infusion but were the same in both groups during high-dose insulin infusion, whereas stimulation of glucose R(d) was greater in lean than obese subjects across the entire physiological range of plasma insulin. CONCLUSIONS Endogenous glucose production and adipose tissue lipolytic rate are both very sensitive to small increases in circulating insulin, whereas stimulation of muscle glucose uptake is minimal until high physiological plasma insulin concentrations are reached. Hyperinsulinemia within the normal physiological range can compensate for both liver and adipose tissue insulin resistance, but not skeletal muscle insulin resistance, in obese people who have normal glucose tolerance.
Collapse
Affiliation(s)
- Caterina Conte
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | | | | | | | | | | |
Collapse
|
47
|
Wang X, Smith GI, Patterson BW, Reeds DN, Kampelman J, Magkos F, Mittendorfer B. Testosterone increases the muscle protein synthesis rate but does not affect very-low-density lipoprotein metabolism in obese premenopausal women. Am J Physiol Endocrinol Metab 2012; 302:E740-6. [PMID: 22252942 PMCID: PMC3311295 DOI: 10.1152/ajpendo.00533.2011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Men and women with hyperandrogenemia have a more proatherogenic plasma lipid profile [e.g., greater triglyceride (TG) and total and low-density lipoprotein-cholesterol and lower high-density lipoprotein-cholesterol concentrations] than healthy premenopausal women. Furthermore, castration of male rats markedly reduces testosterone availability below normal and decreases plasma TG concentration, and testosterone replacement reverses this effect. Testosterone is, therefore, thought to be an important regulator of plasma lipid homeostasis. However, little is known about the effect of testosterone on plasma TG concentration and kinetics. Furthermore, testosterone is a potent skeletal muscle protein anabolic agent in men, but its effect on muscle protein turnover in women is unknown. We measured plasma lipid concentrations, hepatic very low density lipoprotein (VLDL)-TG and VLDL-apolipoprotein B-100 secretion rates, and the muscle protein fractional synthesis rate in 10 obese women before and after trandermal testosterone (1.25 g of 1% AndroGel daily) treatment for 3 wk. Serum total and free testosterone concentrations increased (P < 0.05) by approximately sevenfold in response to testosterone treatment, reaching concentrations that are comparable to those in women with hyperandrogenemia, but lower than the normal range for eugonadal men. Except for a small (∼10%) decrease in plasma high-density lipoprotein particle and cholesterol concentrations (P < 0.04), testosterone therapy had no effect on plasma lipid concentrations, lipoprotein particle sizes, and hepatic VLDL-TG and VLDL-apolipoprotein B-100 secretion rates (all P > 0.05); the muscle protein fractional synthesis rate, however, increased by ∼45% (P < 0.001). We conclude that testosterone is a potent skeletal muscle protein anabolic agent, but not an important regulator of plasma lipid homeostasis in obese women.
Collapse
Affiliation(s)
- Xuewen Wang
- Washington Univ. School of Medicine, Division of Geriatrics & Nutritional Science, St. Louis, MO 63110, USA
| | | | | | | | | | | | | |
Collapse
|
48
|
Koutsari C, Mundi MS, Ali AH, Jensen MD. Storage rates of circulating free fatty acid into adipose tissue during eating or walking in humans. Diabetes 2012; 61:329-38. [PMID: 22228715 PMCID: PMC3266422 DOI: 10.2337/db11-0748] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We measured subcutaneous adipose tissue free fatty acid (FFA) storage rates in postprandial and walking conditions to better understand the contributions of this pathway to body fat distribution. Palmitate tracers were infused intravenously and fat biopsies collected to measure palmitate storage in upper- (UBSQ) and lower-body subcutaneous (LBSQ) fat in 41 (17 men) and 40 (16 men) volunteers under postprandial and under postabsorptive walking conditions, respectively. Postprandial palmitate storage was greater in women than men in UBSQ (0.50±0.25 vs. 0.33±0.37 μmol⋅kg fat(-1)⋅min(-1); P=0.007) and LBSQ fat (0.37±0.25 vs. 0.22±0.20 μmol⋅kg fat(-1)⋅min(-1); P=0.005); storage rates were significantly greater in UBSQ than LBSQ fat in both sexes. During walking, UBSQ palmitate storage did not differ between sexes, whereas LBSQ storage was greater in women than men (0.40±0.22 vs. 0.25±0.15 μmol⋅kg fat(-1)⋅min(-1); P=0.01). In women only, walking palmitate storage was significantly greater in LBSQ than UBSQ fat. Adipocyte CD36 and diacylglycerol acyltransferase (DGAT) correlated with LBSQ palmitate storage in the postprandial and walking condition, respectively. We conclude that UBSQ fat is the preferred postprandial FFA storage depot for both sexes, whereas walking favors storage in LBSQ fat in women. Transmembrane transport (CD36) and esterification into triglycerides (DGAT) may be rate-limiting steps for LBSQ FFA storage during feeding and exercise.
Collapse
|
49
|
Ramos-Roman MA, Sweetman L, Valdez MJ, Parks EJ. Postprandial changes in plasma acylcarnitine concentrations as markers of fatty acid flux in overweight and obesity. Metabolism 2012; 61:202-12. [PMID: 21820684 PMCID: PMC3219812 DOI: 10.1016/j.metabol.2011.06.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/08/2011] [Accepted: 06/09/2011] [Indexed: 12/25/2022]
Abstract
This study determined whether reductions in postprandial plasma nonesterified fatty acid (FFA) flux would lead to reductions in plasma acylcarnitine (AC) concentrations. Plasma AC was measured by liquid chromatography with tandem mass spectrometry in the fasting state and over 6 hours after a high-fat (50% energy) meal was fed to 16 overweight and obese subjects with a wide range of insulin sensitivities. Body composition was measured by dual-energy x-ray absorptiometry; insulin sensitivity by insulin-modified, frequently sampled intravenous glucose tolerance test; substrate oxidation by indirect calorimetry; blood metabolite and hormone concentrations biochemically; and fatty acid flux by using stable isotope tracers. Lean body mass and fasting fat oxidation correlated positively (r > 0.522, P < .05), whereas glucose oxidation correlated negatively (r < -0.551, P < .04), with fasting AC. Postprandially, plasma glucose, insulin, and triglyceride concentrations increased; and FFA concentrations decreased significantly. The responses of plasma AC species depended on chain length and saturation, with C14:0, C16:0, and C18:0 remaining unchanged, and unsaturated species (eg, C14:1, C14:2) falling significantly (21%-46%, P < .03). Postmeal nadir AC concentrations were positively associated with lean body mass, postprandial fatty acid flux, and FFA concentrations (r > 0.515, P < .05). By contrast, nadir AC correlated negatively with insulin sensitivity and spillover of meal-derived fatty acids (r < -0.528, P < .04). Conditions that impact fatty acid flux contribute to the control of postprandial plasma AC concentrations. These data underscore the need for a better understanding of postprandial fatty acid oxidation and dietary fat delivery in the setting of adipose insulin resistance to determine how postprandial lipemia contributes to chronic disease risk.
Collapse
Affiliation(s)
- Maria A. Ramos-Roman
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-8857
| | - Lawrence Sweetman
- Institute of Metabolic Disease, Baylor Research Institute, 3812 Elm Street, Dallas, TX 75226
| | - Maressa J. Valdez
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390-9052
| | - Elizabeth J. Parks
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390-9052
- Corresponding author: Elizabeth J. Parks, Ph.D., Center for Human Nutrition, 5323 Harry Hines Blvd, Dallas, TX 75390-9052, , Phone: (214) 648-2054, Fax: (214) 648-2269
| |
Collapse
|
50
|
Notch-ligand expression by NALT dendritic cells regulates mucosal Th1- and Th2-type responses. Biochem Biophys Res Commun 2011; 418:6-11. [PMID: 22200492 DOI: 10.1016/j.bbrc.2011.12.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 12/12/2011] [Indexed: 02/07/2023]
Abstract
Our previous studies showed that an adenovirus (Ad) serotype 5 vector expressing Flt3 ligand (Ad-FL) as nasal adjuvant activates CD11c(+) dendritic cells (DCs) for the enhancement of antigen (Ag)-specific IgA antibody (Ab) responses. In this study, we examined the molecular mechanism for activation of CD11c(+) DCs and their roles in induction of Ag-specific Th1- and Th2-cell responses. Ad-FL activated CD11c(+) DCs expressed increased levels of the Notch ligand (L)-expression and specific mRNA. When CD11c(+) DCs from various mucosal and systemic lymphoid tissues of mice given nasal OVA plus Ad-FL were cultured with CD4(+) T cells isolated from non-immunized OVA TCR-transgenic (OT II) mice, significantly increased levels of T cell proliferative responses were noted. Furthermore, Ad-FL activated DCs induced IFN-γ, IL-2 and IL-4 producing CD4(+) T cells. Of importance, these APC functions by Ad-FL activated DCs were down-regulated by blocking Notch-Notch-L pathway. These results show that Ad-FL induces CD11c(+) DCs to the express Notch-ligands and these activated DCs regulate the induction of Ag-specific Th1- and Th2-type cytokine responses.
Collapse
|