1
|
Galli M, Hameed A, Żbikowski A, Zabielski P. Aquaporins in insulin resistance and diabetes: More than channels! Redox Biol 2021; 44:102027. [PMID: 34090243 PMCID: PMC8182305 DOI: 10.1016/j.redox.2021.102027] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/09/2021] [Accepted: 05/24/2021] [Indexed: 12/12/2022] Open
Abstract
Aquaporins (AQPs) are part of the family of the integral membrane proteins. Their function is dedicated to the transport of water, glycerol, ammonia, urea, H2O2, and other small molecules across the biological membranes. Although for many years they were scarcely considered, AQPs have a relevant role in the development of many diseases. Recent discoveries suggest, that AQPs may play an important role in the process of fat accumulation and regulation of oxidative stress, two crucial aspects of insulin resistance and type-2 diabetes (T2D). Insulin resistance (IR) and T2D are multi-faceted systemic diseases with multiple connections to obesity and other comorbidities such as hypertension, dyslipidemia and metabolic syndrome. Both IR and T2D transcends different tissues and organs, creating the maze of mutual relationships between adipose fat depots, skeletal muscle, liver and other insulin-sensitive organs. AQPs with their heterogenous properties, distinctive tissue distribution and documented involvement in both the lipid metabolism and regulation of the oxidative stress appear to be feasible candidates in the search for the explanation to this third-millennium plague. A lot of research has been assigned to adipose tissue AQP7 and liver tissue AQP9, clarifying their relationship and coordinated work in the induction of hepatic insulin resistance. Novel research points also to other aquaporins, such as AQP11 which may be associated with the induction of insulin resistance and T2D through its involvement in hydrogen peroxide transport. In this review we collected recent discoveries in the field of AQP's involvement in the insulin resistance and T2D. Novel paths which connect AQPs with metabolic disorders can give new fuel to the research on obesity, insulin resistance and T2D - one of the most worrying problems of the modern society. Presentation of the current knowledge on the involvement of aquaporins in disease state. Overview on latest research regarding insulin resistance and AQPs. Conceptualisation of an AQPs network involved regulation of lipid-related metabolism.
Collapse
Affiliation(s)
- Mauro Galli
- Department of Medical Biology, Medical University of Bialystok, 15-089, Bialystok, Poland.
| | - Ahsan Hameed
- Clinical Research Center, Medical University of Bialystok, 15-089, Bialystok, Poland.
| | - Arkadiusz Żbikowski
- Department of Medical Biology, Medical University of Bialystok, 15-089, Bialystok, Poland.
| | - Piotr Zabielski
- Department of Medical Biology, Medical University of Bialystok, 15-089, Bialystok, Poland.
| |
Collapse
|
2
|
Bacha F, Bartz SK, Puyau M, Adolph A, Sharma S. Metabolic flexibility across the spectrum of glycemic regulation in youth. JCI Insight 2021; 6:146000. [PMID: 33616083 PMCID: PMC7934924 DOI: 10.1172/jci.insight.146000] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/13/2021] [Indexed: 12/29/2022] Open
Abstract
BACKGROUNDMetabolic flexibility (MF) refers to the relative ability to utilize lipid and carbohydrate substrates and to transition between them. It is not clear whether MF is impaired in obese youth and what the determining factors are.METHODSWe investigated the determinants of MF (increased respiratory exchange ratio [ΔRER] under insulin-stimulated conditions) in pubertal youth (n = 104; 15.6 ± 1.8 years) with obesity across the spectrum of glucose tolerance compared with normal weight (NW) controls, including body composition (fat-free mass [FFM], %body fat), visceral adipose fat (VAT) (MRI), glycemia, and insulin sensitivity (IS) [3-hour hyperinsulinemic-euglycemic clamp with measurement of lipolysis ([2H5] glycerol), free fatty acids (FFAs), and RER (indirect calorimetry)].RESULTSYouth with prediabetes and type 2 diabetes had lower ΔRER and oxidative and nonoxidative glucose disposal compared with NW, with no significant difference in ΔRER between NW and obese with normal glucose tolerance. In multiple regression analysis, ISFFM (β = 0.4, P = 0.004), percentage suppression of FFAs (r = 0.26, P = 0.007), and race/ethnicity (β = -0.23, P = 0.02) contributed to the variance in ΔRER (R2 = 0.30, P < 0.001) independent of percentage body fat (or VAT), sex, Tanner stage, and hemoglobin A1c.ConclusionMF is defective at the extreme of the metabolic phenotype in obese youth with dysglycemia related to a defect in IS limiting substrate utilization.FUNDINGUSDA/ARS Project Number 3092-51000-057.
Collapse
Affiliation(s)
- Fida Bacha
- United States Department of Agriculture Agricultural Research Service (USDA/ARS) Children's Nutrition Research Center, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas, USA.,Division of Pediatric Endocrinology and Diabetes, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas, USA
| | - Sara Klinepeter Bartz
- United States Department of Agriculture Agricultural Research Service (USDA/ARS) Children's Nutrition Research Center, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas, USA.,Division of Pediatric Endocrinology and Diabetes, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas, USA
| | - Maurice Puyau
- United States Department of Agriculture Agricultural Research Service (USDA/ARS) Children's Nutrition Research Center, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas, USA
| | - Anne Adolph
- United States Department of Agriculture Agricultural Research Service (USDA/ARS) Children's Nutrition Research Center, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas, USA
| | - Susan Sharma
- United States Department of Agriculture Agricultural Research Service (USDA/ARS) Children's Nutrition Research Center, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas, USA
| |
Collapse
|
3
|
Palmeiro-Silva YK, Aravena RI, Ossio L, Parro Fluxa J. Effects of Daily Consumption of an Aqueous Dispersion of Free-Phytosterols Nanoparticles on Individuals with Metabolic Syndrome: A Randomised, Double-Blind, Placebo-Controlled Clinical Trial. Nutrients 2020; 12:nu12082392. [PMID: 32785036 PMCID: PMC7468816 DOI: 10.3390/nu12082392] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/04/2020] [Accepted: 08/05/2020] [Indexed: 11/16/2022] Open
Abstract
Metabolic syndrome (MS) affects up to 40% of the population and is associated with heart failure, stroke and diabetes. Phytosterols (PS) could help to manage one or more MS criteria. The purpose of this study was to evaluate the therapeutic effect of daily supplementation of an aqueous dispersion of 2 g of free-phytosterols nanoparticles in individuals with MS over six months of intervention, compared with placebo. This double-blind study included 202 participants with MS randomly assigned into phytosterol (n = 102) and placebo (n = 100) groups. Participants were assessed at baseline, 4, 12 and 24 weeks. General health questions, anthropometric measurements and blood parameters were analysed. At week 24, the proportion of participants with high triglycerides (≥150 mg/dL) in the phytosterol group was 15.65% lower than in the placebo group (p-value = 0.023). Similarly, half of the participants in the phytosterol group decreased their waist circumference up to 4 cm compared with 0 cm in the placebo group (p-value = 0.0001). We reported no adverse effects (diarrhoea or vitamin D reduction); nonetheless, almost 70% of participants in the phytosterol group self-reported an improvement in bowel habits. Daily intake of free-PS nanoparticles improved some MS criteria; therefore, it might be a promising adjuvant therapy for individuals with MS (NCT02969720).
Collapse
Affiliation(s)
- Yasna K. Palmeiro-Silva
- School of Nursing, Universidad de los Andes, Las Condes 7550000, Chile; (L.O.); (J.P.F.)
- Correspondence: ; Tel./Fax: +56-2-226181332
| | - Raúl I. Aravena
- Department of Chemical Engineering, Imperial College London, London SW7 2BX, UK;
| | - Lisette Ossio
- School of Nursing, Universidad de los Andes, Las Condes 7550000, Chile; (L.O.); (J.P.F.)
| | - Javiera Parro Fluxa
- School of Nursing, Universidad de los Andes, Las Condes 7550000, Chile; (L.O.); (J.P.F.)
| |
Collapse
|
4
|
Cree-Green M, Wiromrat P, Stuppy JJ, Thurston J, Bergman BC, Baumgartner AD, Bacon S, Scherzinger A, Pyle L, Nadeau KJ. Muscle Insulin Resistance in Youth with Obesity and Normoglycemia is Associated with Altered Fat Metabolism. Obesity (Silver Spring) 2019; 27:2046-2054. [PMID: 31659873 PMCID: PMC6897373 DOI: 10.1002/oby.22658] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 08/27/2019] [Indexed: 11/10/2022]
Abstract
OBJECTIVE This study aimed to phenotype and compare adipose, hepatic, and muscle insulin sensitivity (IS) in a diet- and physical activity-controlled cohort of normoglycemic youth with obesity with that of participants without obesity (controls) to distinguish early metabolic abnormalities in pediatric obesity. METHODS Thirty-eight participants (17 in the control group [BMI < 85th percentile] and 21 youth with obesity [BMI ≥ 95th percentile]; age: 12-21 years; 76% female; Tanner stage 4-5; sedentary) were enrolled. Tissue-specific IS was measured using a four-phase hyperinsulinemic-euglycemic clamp with glucose and glycerol isotope tracers to assess suppression of endogenous glucose release and lipolysis by insulin. Intramyocellular lipid content was assessed by 1 H-magnetic resonance spectroscopy, and hepatic fat fraction (HFF) and visceral fat were assessed by magnetic resonance imaging. Calf-muscle mitochondrial activity was measured with exercise-stimulated 31 P-magnetic resonance spectroscopy. RESULTS Youth with obesity had higher HFF (P < 0.001), visceral fat (P = 0.024), and intramyocellular lipid content (P = 0.017) and lower muscle (glucose clearance rate [P < 0.001]), adipose (P < 0.0001), and hepatic IS (P < 0.003). Mitochondria postexercise response was not different. In participants with obesity, muscle IS inversely correlated with HFF (r = 0.700, P = 0.002) and suppressed free fatty acid concentrations (r = -0.65, P = 0.003). CONCLUSIONS Inactive normoglycemic youth with obesity had decreased muscle, adipose, and hepatic IS. Free fatty acids and liver fat were inversely associated with muscle IS, which argues for lipid-targeted interventions.
Collapse
Affiliation(s)
- Melanie Cree-Green
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Pattara Wiromrat
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Jacob J. Stuppy
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO
- Department of Biomedical Sciences and Biotechnology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Jessica Thurston
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO
| | - Bryan C. Bergman
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Amy D. Baumgartner
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Samantha Bacon
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Ann Scherzinger
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Laura Pyle
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO
| | - Kristen J. Nadeau
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO
| |
Collapse
|
5
|
Petersen MC, Shulman GI. Mechanisms of Insulin Action and Insulin Resistance. Physiol Rev 2018; 98:2133-2223. [PMID: 30067154 PMCID: PMC6170977 DOI: 10.1152/physrev.00063.2017] [Citation(s) in RCA: 1374] [Impact Index Per Article: 229.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/22/2018] [Accepted: 03/24/2018] [Indexed: 12/15/2022] Open
Abstract
The 1921 discovery of insulin was a Big Bang from which a vast and expanding universe of research into insulin action and resistance has issued. In the intervening century, some discoveries have matured, coalescing into solid and fertile ground for clinical application; others remain incompletely investigated and scientifically controversial. Here, we attempt to synthesize this work to guide further mechanistic investigation and to inform the development of novel therapies for type 2 diabetes (T2D). The rational development of such therapies necessitates detailed knowledge of one of the key pathophysiological processes involved in T2D: insulin resistance. Understanding insulin resistance, in turn, requires knowledge of normal insulin action. In this review, both the physiology of insulin action and the pathophysiology of insulin resistance are described, focusing on three key insulin target tissues: skeletal muscle, liver, and white adipose tissue. We aim to develop an integrated physiological perspective, placing the intricate signaling effectors that carry out the cell-autonomous response to insulin in the context of the tissue-specific functions that generate the coordinated organismal response. First, in section II, the effectors and effects of direct, cell-autonomous insulin action in muscle, liver, and white adipose tissue are reviewed, beginning at the insulin receptor and working downstream. Section III considers the critical and underappreciated role of tissue crosstalk in whole body insulin action, especially the essential interaction between adipose lipolysis and hepatic gluconeogenesis. The pathophysiology of insulin resistance is then described in section IV. Special attention is given to which signaling pathways and functions become insulin resistant in the setting of chronic overnutrition, and an alternative explanation for the phenomenon of ‟selective hepatic insulin resistanceˮ is presented. Sections V, VI, and VII critically examine the evidence for and against several putative mediators of insulin resistance. Section V reviews work linking the bioactive lipids diacylglycerol, ceramide, and acylcarnitine to insulin resistance; section VI considers the impact of nutrient stresses in the endoplasmic reticulum and mitochondria on insulin resistance; and section VII discusses non-cell autonomous factors proposed to induce insulin resistance, including inflammatory mediators, branched-chain amino acids, adipokines, and hepatokines. Finally, in section VIII, we propose an integrated model of insulin resistance that links these mediators to final common pathways of metabolite-driven gluconeogenesis and ectopic lipid accumulation.
Collapse
Affiliation(s)
- Max C Petersen
- Departments of Internal Medicine and Cellular & Molecular Physiology, Howard Hughes Medical Institute, Yale University School of Medicine , New Haven, Connecticut
| | - Gerald I Shulman
- Departments of Internal Medicine and Cellular & Molecular Physiology, Howard Hughes Medical Institute, Yale University School of Medicine , New Haven, Connecticut
| |
Collapse
|
6
|
Abstract
The liver is crucial for the maintenance of normal glucose homeostasis - it produces glucose during fasting and stores glucose postprandially. However, these hepatic processes are dysregulated in type 1 and type 2 diabetes mellitus, and this imbalance contributes to hyperglycaemia in the fasted and postprandial states. Net hepatic glucose production is the summation of glucose fluxes from gluconeogenesis, glycogenolysis, glycogen synthesis, glycolysis and other pathways. In this Review, we discuss the in vivo regulation of these hepatic glucose fluxes. In particular, we highlight the importance of indirect (extrahepatic) control of hepatic gluconeogenesis and direct (hepatic) control of hepatic glycogen metabolism. We also propose a mechanism for the progression of subclinical hepatic insulin resistance to overt fasting hyperglycaemia in type 2 diabetes mellitus. Insights into the control of hepatic gluconeogenesis by metformin and insulin and into the role of lipid-induced hepatic insulin resistance in modifying gluconeogenic and net hepatic glycogen synthetic flux are also discussed. Finally, we consider the therapeutic potential of strategies that target hepatosteatosis, hyperglucagonaemia and adipose lipolysis.
Collapse
Affiliation(s)
- Max C Petersen
- Department of Internal Medicine, Yale School of Medicine
- Department of Cellular &Molecular Physiology, Yale School of Medicine
| | | | - Gerald I Shulman
- Department of Internal Medicine, Yale School of Medicine
- Department of Cellular &Molecular Physiology, Yale School of Medicine
- Howard Hughes Medical Institute, Yale School of Medicine, New Haven, Connecticut 06520, USA
| |
Collapse
|
7
|
Chu L, Morrison KM, Riddell MC, Raha S, Timmons BW. No difference in exogenous carbohydrate oxidation during exercise in children with and without impaired glucose tolerance. J Appl Physiol (1985) 2016; 121:724-9. [PMID: 27493197 DOI: 10.1152/japplphysiol.00419.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/01/2016] [Indexed: 11/22/2022] Open
Abstract
The capacity to match carbohydrate (CHO) utilization with availability is impaired in insulin-resistant, obese adults at rest. Understanding exogenous carbohydrate (CHOexo) oxidation during exercise and its association to insulin resistance (IR) is important, especially in children at risk for type 2 diabetes. Our objective was to examine the oxidative efficiency of CHOexo during exercise in obese children with normal glucose tolerance (NGT) or impaired glucose tolerance (IGT). Children attended two visits and were identified as NGT (n = 22) or IGT (n = 12) based on 2-h oral glucose tolerance test (OGTT) glucose levels of <7.8 mmol/l or ≥7.8 mmol/l, respectively. Anthropometry, body composition, and aerobic fitness (V̇o2max) were assessed. Insulin and glucose at baseline, 30, 60, 90, and 120 min during the OGTT were used to calculate measures of insulin sensitivity. On a separate day, a (13)C-enriched CHO drink was ingested before exercise (3 × 20 min bouts) at 45% V̇o2max Breath measurements were collected to calculate CHOexo oxidative efficiency. CHOexo oxidative efficiency during exercise was similar in IGT (17.0 ± 3.6%) compared with NGT (17.1 ± 4.4%) (P = 0.90) despite lower whole body insulin sensitivity in IGT at rest (P = 0.02). Area under the curve for insulin (AUCins) measured at rest during the OGTT was greater in IGT compared with NGT (P = 0.04). The ability of skeletal muscle to utilize CHOexo was not impaired during exercise in children with IGT.
Collapse
Affiliation(s)
- Lisa Chu
- Child Health and Exercise Medicine Program, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | | | - Michael C Riddell
- School of Kinesiology & Health Science, York University, Toronto, Ontario, Canada
| | - Sandeep Raha
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada; and
| | - Brian W Timmons
- Child Health and Exercise Medicine Program, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada;
| |
Collapse
|
8
|
Park MH, Nam YH, Han JS. Sargassum coreanum extract alleviates hyperglycemia and improves insulin resistance in db/db diabetic mice. Nutr Res Pract 2015; 9:472-9. [PMID: 26425276 PMCID: PMC4575959 DOI: 10.4162/nrp.2015.9.5.472] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/08/2015] [Accepted: 04/13/2015] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND/OBJECTIVES The goal of this study was to examine the effect of Sargassum coreanum extract (SCE) on blood glucose concentration and insulin resistance in C57BL-KsJ-db/db mice. MATERIALS/METHODS For 6 weeks, male C57BL/KsJ-db/db mice were administrated SCE (0.5%, w/w), and rosiglitazone (0.005%, w/w). RESULTS A supplement of the SCE for 6 weeks induced a significant reduction in blood glucose and glycosylated hemoglobin concentrations, and it improved hyperinsulinemia compared to the diabetic control db/db mice. The glucokinase activity in the hepatic glucose metabolism increased in the SCE-supplemented db/db mice, while phosphoenolpyruvate carboxykinase and glucose-6-phosphatase activities in the SCE-supplemented db/db mice were significantly lower than those in the diabetic control db/db mice. The homeostatic index of insulin resistance was lower in the SCE-supplemented db/db mice than in the diabetic control db/db mice. CONCLUSIONS These results suggest that a supplement of the SCE lowers the blood glucose concentration by altering the hepatic glucose metabolic enzyme activities and improves insulin resistance.
Collapse
Affiliation(s)
- Mi Hwa Park
- Department of Food and Nutrition, College of Medical and Life Science, Silla University, Busan 617-736, Korea
| | - Young Hwa Nam
- Department of Food Science and Nutrition, Pusan National University, Busan 609-735, Korea
| | - Ji-Sook Han
- Department of Food Science and Nutrition & Research Institute of Ecology for the Elderly, Pusan National University, 63 Beon-gil 2, Busandaehag-ro, Geumjeong-gu, Busan 609-735, Korea
| |
Collapse
|
9
|
Cheng Q, Zhang X, Wang O, Liu J, Cai S, Wang R, Zhou F, Ji B. Anti-diabetic effects of the ethanol extract of a functional formula diet in mice fed with a fructose/fat-rich combination diet. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2015; 95:401-408. [PMID: 24817112 DOI: 10.1002/jsfa.6737] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 04/23/2014] [Accepted: 05/06/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND Rhizoma dioscorea, Lycium barbarum, Prunella vulgaris and hawthorn are well known in both traditional food and folk medicine. Each of these plants reportedly possesses beneficial effects in the treatment of diabetes. In this study an anti-diabetic health-promoting diet was formulated by mixing the herbs in a ratio of 6:4:2:3, and the anti-diabetic effect and underlying mechanism were elucidated in vivo. RESULTS Compared with the model control group, the formula, especially its ethanol extract (EF), could improve glucose intolerance and normalize the lipid profile. The mechanisms responsible for the amelioration of glucose and lipid metabolism in mice were an increase in peripheral and hepatic insulin sensitivity, a decrease in serum free fatty acid level, enhanced hepatic glucokinase activity and glycogen content and improved serum antioxidant activity. Hepatic histopathological examination also showed that EF administration markedly decreased fatty deposits in the liver of mice. CONCLUSION The results of the present study demonstrated that the prepared functional formula diet is a potent alternative as an anti-diabetic health-promoting diet.
Collapse
Affiliation(s)
- Qian Cheng
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, No. 17 Tsinghua East Road, Haidian District, Beijing, 100083, China
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Kelsey MM, Forster JE, Van Pelt RE, Reusch JEB, Nadeau KJ. Adipose tissue insulin resistance in adolescents with and without type 2 diabetes. Pediatr Obes 2014; 9:373-80. [PMID: 23861170 PMCID: PMC4285336 DOI: 10.1111/j.2047-6310.2013.00189.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 05/17/2013] [Accepted: 05/24/2013] [Indexed: 12/30/2022]
Abstract
BACKGROUND The incidence of type 2 diabetes mellitus (T2D) is increasing in youth, yet little is known about the underlying pathophysiology. Decreased insulin suppression of lipolysis and elevated non-esterified free fatty acid (NEFA) concentrations are known to be associated with insulin resistance and T2D in adults, but less is known about the relationship in adolescents. OBJECTIVES This study aimed to assess adipose tissue insulin resistance (IR; insulin suppression of lipolysis) and its metabolic correlates in lean, obese and T2D adolescents. METHODS Forty-seven lean, obese and T2D youth underwent hyperinsulinaemic (80 mU*m(-2) *min(-1)) euglycaemic clamps. NEFAs were measured at baseline and during steady state. Insulin-mediated suppression of lipolysis (%NEFA suppression from baseline) was calculated, and metabolic risk factors were assessed by %NEFA suppression tertile. RESULTS There was expected variability in %NEFA suppression within obese and T2D youth, but a subset had significantly reduced suppression of lipolysis. NEFA suppression tertile was significantly inversely associated with fasting triglycerides (P = 0.0001), log alanine aminotransferase (ALT; P = 0.02) and low-density lipoprotein cholesterol (P = 0.0002). CONCLUSIONS Marked adipose tissue IR occurs in some obese and T2D adolescents, which may result in release of triglycerides into the circulation and liver deposition of fatty acids, as evidenced by higher ALT in poor NEFA suppressors.
Collapse
Affiliation(s)
- Megan M Kelsey
- University of Colorado Anschutz Medical Campus, Department of Pediatrics,Children’s Hospital Colorado
| | - Jeri E Forster
- University of Colorado Anschutz Medical Campus, Department of Biostatistics and Informatics, Colorado School of Public Health
| | | | - Jane EB Reusch
- University of Colorado Anschutz Medical Campus, Department of Medicine
| | - Kristen J Nadeau
- University of Colorado Anschutz Medical Campus, Department of Pediatrics,Children’s Hospital Colorado
| |
Collapse
|
11
|
Chu L, Riddell MC, Schneiderman JE, McCrindle BW, Hamilton JK. The effect of puberty on fat oxidation rates during exercise in overweight and normal-weight girls. J Appl Physiol (1985) 2014; 116:76-82. [DOI: 10.1152/japplphysiol.00888.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Excess weight is often associated with insulin resistance (IR) and may disrupt fat oxidation during exercise. This effect is further modified by puberty. While studies have shown that maximal fat oxidation rates (FOR) during exercise decrease with puberty in normal-weight (NW) and overweight (OW) boys, the effect of puberty in NW and OW girls is unclear. Thirty-three NW and OW girls ages 8–18 yr old completed a peak aerobic capacity test on a cycle ergometer. FOR were calculated during progressive submaximal exercise. Body composition and Tanner stage were determined. For each participant, a best-fit polynomial curve was constructed using fat oxidation vs. exercise intensity to estimate max FOR. In a subset of the girls, IR derived from an oral glucose tolerance test ( n = 20), and leptin and adiponectin levels ( n = 11) were assessed in relation to FOR. NW pre-early pubertal girls had higher max FOR [6.9 ± 1.4 mg·kg fat free mass (FFM)−1·min−1] than NW mid-late pubertal girls (2.2 ± 0.9 mg·kg FFM−1·min−1) ( P = 0.002), OW pre-early pubertal girls (3.8 ± 2.1 mg·kg FFM−1·min−1), and OW mid-late pubertal girls (3.3 ± 0.9 mg·kg FFM−1·min−1) ( P < 0.05). Bivariable analyses showed positive associations between FOR with homeostatic model assessment of IR ( P = 0.001), leptin ( P < 0.001), and leptin-to-adiponectin ratio ( P = 0.001), independent of percent body fat. Max FOR decreased in NW girls during mid-late puberty; however, this decrease associated with puberty was blunted in OW girls due to lower FOR in pre-early puberty. The presence of IR due to obesity potentially masks the effect of puberty on FOR during exercise in girls.
Collapse
Affiliation(s)
- L. Chu
- Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- School of Kinesiology and Health Sciences, Faculty of Health, York University, Toronto, Ontario, Canada
| | - M. C. Riddell
- School of Kinesiology and Health Sciences, Faculty of Health, York University, Toronto, Ontario, Canada
| | - J. E. Schneiderman
- Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- University of Toronto, Toronto, Ontario, Canada
| | - B. W. McCrindle
- University of Toronto, Toronto, Ontario, Canada
- Labatt Family Heart Centre, The Hospital for Sick Children, Toronto, Ontario, Canada; and
| | - J. K. Hamilton
- Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- University of Toronto, Toronto, Ontario, Canada
- Division of Endocrinology, The Hospital for Sick Children, Toronto, Ontario, Canada
| |
Collapse
|
12
|
Jocken JWE, Goossens GH, Boon H, Mason RR, Essers Y, Havekes B, Watt MJ, van Loon LJ, Blaak EE. Insulin-mediated suppression of lipolysis in adipose tissue and skeletal muscle of obese type 2 diabetic men and men with normal glucose tolerance. Diabetologia 2013; 56:2255-65. [PMID: 23907381 PMCID: PMC3764323 DOI: 10.1007/s00125-013-2995-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 06/18/2013] [Indexed: 12/29/2022]
Abstract
AIMS/HYPOTHESIS Impaired regulation of lipolysis and accumulation of lipid intermediates may contribute to obesity-related insulin resistance and type 2 diabetes mellitus. We investigated insulin-mediated suppression of lipolysis in abdominal subcutaneous adipose tissue (AT) and skeletal muscle (SM) of obese men with normal glucose tolerance (NGT) and obese type 2 diabetic men. METHODS Eleven NGT men and nine long-term diagnosed type 2 diabetic men (7 ± 1 years), matched for age (58 ± 2 vs 62 ± 2 years), BMI (31.4 ± 0.6 vs 30.5 ± 0.6 kg/m(2)) and [Formula: see text] (28.9 ± 1.5 vs 29.5 ± 2.4 ml kg(-1) min(-1)) participated in this study. Interstitial glycerol concentrations in AT and SM were assessed using microdialysis during a 1 h basal period and a 6 h stepwise hyperinsulinaemic-euglycaemic clamp (8, 20 and 40 mU m(-2) min(-1)). AT and SM biopsies were collected to investigate underlying mechanisms. RESULTS Hyperinsulinaemia suppressed interstitial SM glycerol concentrations less in men with type 2 diabetes (-7 ± 6%, -13 ± 9% and -27 ± 9%) compared with men with NGT (-21 ± 7%, -38 ± 8% and -53 ± 8%) (p = 0.014). This was accompanied by increased circulating fatty acid and glycerol concentrations, a lower glucose infusion rate (21.8 ± 3.1 vs 30.5 ± 2.0 μmol kg body weight(-1) min(-1); p < 0.05), higher hormone-sensitive lipase (HSL) serine 660 phosphorylation, increased saturated diacylglycerol (DAG) lipid species in the muscle membrane and increased protein kinase C (PKC) activation in type 2 diabetic men vs men with NGT. No significant differences in insulin-mediated reduction in AT interstitial glycerol were observed between groups. CONCLUSIONS/INTERPRETATION Our results suggest that a blunted insulin-mediated suppression of SM lipolysis may promote the accumulation of membrane saturated DAG, aggravating insulin resistance, at least partly mediated by PKC. This may represent an important mechanism involved in the progression of insulin resistance towards type 2 diabetes. TRIAL REGISTRATION ClinicalTrials.gov NCT01680133.
Collapse
Affiliation(s)
- Johan W E Jocken
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University Medical Centre+, PO Box 616, 6200 MD, Maastricht, the Netherlands.
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Frohnert BI, Jacobs DR, Steinberger J, Moran A, Steffen LM, Sinaiko AR. Relation between serum free fatty acids and adiposity, insulin resistance, and cardiovascular risk factors from adolescence to adulthood. Diabetes 2013; 62:3163-9. [PMID: 23670973 PMCID: PMC3749355 DOI: 10.2337/db12-1122] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The objective of this study was to describe longitudinal relations of serum total free fatty acids (FFAs) to insulin resistance (IR) and cardiovascular (CV) risk factors from adolescence into adulthood. The cohort included participants in a longitudinal study of obesity and IR with complete data, including anthropometric measures, FFAs, IR measured by euglycemic clamp, blood pressure, fasting serum lipids, and insulin at mean 15 and 22 years of age (n = 207) and their parents (n = 272). FFAs and IR were not significantly related at mean 15 years of age but were significantly related at mean age 22 years. FFA did not relate to BMI at either age. FFA at 15 years of age estimated IR at 22 years of age. In parents (mean age 51 years), FFA was significantly correlated with BMI, percent body fat, systolic blood pressure, LDL, and IR. Associations with all risk factors except IR in parents were attenuated by adjustment for BMI. Most 22 years of age correlations with parents were higher than corresponding 15 years of age correlations. This study finds that FFA is associated with IR starting in young adulthood. The relation between FFA and CV risk factors does not become significant until later adulthood. The results support a significant impact of early metabolic dysfunction on later CV risk.
Collapse
Affiliation(s)
- Brigitte I Frohnert
- Department of Pediatrics, Medical School, University of Minnesota, Minneapolis, Minnesota, USA.
| | | | | | | | | | | |
Collapse
|
14
|
Yamazaki H, Zawalich KC, Zawalich WS. Physiologic implications of phosphoinositides and phospholipase C in the regulation of insulin secretion. J Nutr Sci Vitaminol (Tokyo) 2010; 56:1-8. [PMID: 20354339 DOI: 10.3177/jnsv.56.1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The secretion of insulin from the pancreatic beta-cell must be commensurate to satisfy the insulin requirements of the organism. This cell has a great flexibility to meet these requirements which are increased not only by the ingestion of nutrients (increase of plasma glucose) but also by the sensitivity of target tissues to insulin as well. The insulin secretion is a complex biochemical event regulated by a host of potential second messenger molecules acting alone or in concert. These events include the cation calcium, which gains access to the beta-cell via the opening of voltage-regulated channels, cAMP and phosphoinositide-derived second messenger molecules, generated as a consequence of phospholipase C (PLC) activation. In this review, we focused on phosphoinositides, PLC/Phosphokinase C (PKC) and phosphatidylinositol 3-kinase (PI3K) cascade in the regulation of insulin secretion. We also described our studies on the mechanism of the beta-cell desensitization using perifused islets. It is suggested that a failure of the signaling events contribute to the pathogenesis of diabetes in which the beta-cell can no longer secrete the required amounts of insulin. It has been observed that chronic exposure to high glucose desensitizes the beta-cells to subsequent stimulation. We suggested that the failure of PLC activation can be attributed in the impairment of insulin secretion by chronic sustained glucose exposure. It may contribute to the vicious circle of impaired insulin secretion leading up to diabetes.
Collapse
Affiliation(s)
- Hanae Yamazaki
- Laboratory of Ajinomoto Integrative Research for Advanced Dieting, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
| | | | | |
Collapse
|
15
|
Särnblad S, Ekelund U, Aman J. Dietary fat intake predicts 1-year change in body fat in adolescent girls with type 1 diabetes. Diabetes Care 2006; 29:1227-30. [PMID: 16732000 DOI: 10.2337/dc05-2318] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The purpose of this study was to determine whether objectively measured physical activity and dietary macronutrient intake differentially predict body fat in adolescent girls with type 1 diabetes and control girls. RESEARCH DESIGN AND METHODS This study comprised 23 girls (12-19 years) with type 1 diabetes and 19 age-matched healthy control girls. At baseline, physical activity and energy intake were assessed for 7 consecutive days by accelerometry and a structured food diary, respectively. Body composition was measured by dual-energy X-ray absorptiometry at baseline and after 1 year. RESULTS Fat intake was positively related to a 1-year change in percentage body fat (P = 0.006), after adjustment for total energy intake. No significant interaction was observed (case-control group x main exposure), indicating that the association between fat intake and gain in body fat was similar in both groups. Physical activity did not predict gain in body fat; however, total physical activity was positively associated with a gain in lean body mass (P < 0.01). Girls treated with six daily dosages of insulin increased their percentage of body fat significantly more than those treated with four daily injections (P < 0.05). CONCLUSIONS In this prospective case-control study, we found that fat intake predicted gain in percentage of body fat in both adolescent girls with type 1 diabetes and healthy control girls. The number of daily insulin injections seems to influence the accumulation of body fat in girls with type 1 diabetes.
Collapse
Affiliation(s)
- Stefan Särnblad
- Department of Pediatrics, University Hospital, S-701 85 Orebro, Sweden.
| | | | | |
Collapse
|
16
|
Ferchaud-Roucher V, Pouteau E, Piloquet H, Zaïr Y, Krempf M. Colonic fermentation from lactulose inhibits lipolysis in overweight subjects. Am J Physiol Endocrinol Metab 2005; 289:E716-20. [PMID: 16150956 DOI: 10.1152/ajpendo.00430.2004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
One of the strategies to prevent insulin resistance is to reduce circulating free fatty acids (FFA). The aim of this study is to assess the effect of an oral lactulose load on fatty acid metabolism in overweight subjects. Eight overweight subjects received a primed constant intravenous infusion of [1-(13)C]acetate and of [1,1,2,3,3-(2)H(5)]glycerol for 9 h. After 3 h of tracer infusion, patients ingested 30 g lactulose, or saline solution. Arterialized blood samples were collected every 20 min. Basal plasma concentrations of acetate were similar before and between oral treatments as well as glycerol and FFA concentrations. Plasma acetate turnover was 11.4 +/- 2.4 vs. 10.7 +/- 1.4 micromol.kg(-1).min(-1) [not significant (NS)], and plasma glycerol turnover was 3.8 +/- 0.4 vs. 4.8 +/- 1.9 micromol.kg(-1).min(-1) (NS). After lactulose ingestion, acetate concentration increased twofold and then decreased to baseline. Acetate turnover rate increased to 15.5 +/- 2.2 micromol.kg(-1).min(-1) after lactulose treatment, whereas it was unchanged after saline treatment (10.3 +/- 2.2 micromol.kg(-1).min(-1), P < or = 0.0001). In contrast, FFA concentrations decreased significantly after lactulose ingestion and then increased slowly. Glycerol turnover decreased after lactulose ingestion compared with saline, 2.8 +/- 0.4 vs. 3.5 +/- 0.3 micromol.kg(-1).min(-1) (P < or = 0.05). A significant negative correlation was found between glycerol and acetate turnover after lactulose treatments (r = -0.78, P < or = 0.02). These results showed in overweight subjects a short-term decrease in FFA level and glycerol turnover after lactulose ingestion related to a decrease of lipolysis in close relationship with an increase of acetate production.
Collapse
Affiliation(s)
- V Ferchaud-Roucher
- Centre de Recherche en Nutrition Humaine, Institut National de la Santé et de la Recherche Médicale U539, Nantes, France
| | | | | | | | | |
Collapse
|
17
|
Weiss R, Dufour S, Taksali SE, Tamborlane WV, Petersen KF, Bonadonna RC, Boselli L, Barbetta G, Allen K, Rife F, Savoye M, Dziura J, Sherwin R, Shulman GI, Caprio S. Prediabetes in obese youth: a syndrome of impaired glucose tolerance, severe insulin resistance, and altered myocellular and abdominal fat partitioning. Lancet 2003; 362:951-7. [PMID: 14511928 PMCID: PMC2995523 DOI: 10.1016/s0140-6736(03)14364-4] [Citation(s) in RCA: 366] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Impaired glucose tolerance is common among obese adolescents, but the changes in insulin sensitivity and secretion that lead to this prediabetic state are unknown. We investigated whether altered partitioning of myocellular and abdominal fat relates to abnormalities in glucose homoeostasis in obese adolescents with prediabetes. METHODS We studied 14 obese children with impaired glucose tolerance and 14 with normal glucose tolerance, of similar ages, sex distribution, and degree of obesity. Insulin sensitivity and secretion were assessed by the euglycaemic-hyperinsulinaemic clamp and the hyperglycaemic clamp. Intramyocellular lipid was assessed by proton nuclear magnetic resonance spectroscopy and abdominal fat distribution by magnetic resonance imaging. FINDINGS Peripheral glucose disposal was significantly lower in individuals with impaired than in those with normal glucose tolerance (mean 35.4 [SE 4.0] vs 60.6 [7.2] micromoles per kg lean body mass per min; p=0.023) owing to a reduction in non-oxidative glucose disposal metabolism (storage). Individuals with impaired glucose tolerance had higher intramyocellular lipid content (3.04 [0.43] vs 1.99 [0.19]%, p=0.03), lower abdominal subcutaneous fat (460 [47] vs 626 [39] cm2, p=0.04), and slightly higher visceral fat than the controls (70 [11] vs 47 [6] cm2, p=0.065), resulting in a higher ratio of visceral to subcutaneous fat (0.15 [0.02] vs 0.07 [0.01], p=0.002). Intramyocellular and visceral lipid contents were inversely related to the glucose disposal and non-oxidative glucose metabolism and positively related to the 2 h plasma glucose concentration. INTERPRETATION In obese children and adolescents with prediabetes, intramyocellular and intra-abdominal lipid accumulation is closely linked to the development of severe peripheral insulin resistance.
Collapse
Affiliation(s)
- Ram Weiss
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Kalderon B, Mayorek N, Ben-Yaacov L, Bar-Tana J. Adipose tissue sensitization to insulin induced by troglitazone and MEDICA 16 in obese Zucker rats in vivo. Am J Physiol Endocrinol Metab 2003; 284:E795-803. [PMID: 12488241 DOI: 10.1152/ajpendo.00368.2002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The putative role played by insulin sensitizers in modulating adipose tissue lipolysis in the fasting state was evaluated in obese conscious Zucker rats treated with troglitazone or beta,beta'-tetramethylhexadecanedioic acid (MEDICA 16) and compared with nontreated lean and obese animals. The rates of appearance (R(a)) of glycerol and free fatty acid (FFA), primary intra-adipose reesterification, and secondary reuptake of plasma FFA in adipose fat were measured using constant infusion of stable isotope-labeled [(2)H(5)]glycerol, [2,2-(2)H(2)]palmitate, and radioactive [(3)H]palmitate. The overall lipolytic flux (R(a) glycerol) was increased 1.7- and 1.4-fold in obese animals treated with troglitazone or MEDICA 16, respectively, resulting in increased FFA export (R(a) FFA) in the troglitazone-treated rats. Primary intra-adipose reesterification of lipolysis-derived fatty acids was enhanced twofold by insulin sensitizers, whereas reesterification of plasma fatty acids was unaffected by either treatment. Despite the unchanged R(a) FFA in MEDICA 16 or the increased R(a) FFA induced by troglitazone, very low density lipoprotein production rates were robustly curtailed. Total adipose tissue reesterification, used as an estimate of glucose conversion to glyceride-glycerol, was increased 1.9-fold by treatment with the insulin sensitizers. Our results indicate that, in the fasting state, insulin sensitizers induce, in vivo, a significant activation rather than suppression of adipose tissue lipolysis together with stimulation of glucose conversion to glyceride-glycerol.
Collapse
Affiliation(s)
- Bella Kalderon
- Department of Human Nutrition and Metabolism, Hebrew University Medical School, Jerusalem, Israel 91120.
| | | | | | | |
Collapse
|
19
|
Affiliation(s)
- Francine Ratner Kaufman
- Department of Pediatrics, The Keck School of Medicine, University of Southern California, CA, USA.
| |
Collapse
|
20
|
Shangraw RE, Jahoor F. Lipolysis and lipid oxidation in cirrhosis and after liver transplantation. Am J Physiol Gastrointest Liver Physiol 2000; 278:G967-73. [PMID: 10859227 DOI: 10.1152/ajpgi.2000.278.6.g967] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
On the basis of the finding that plasma glycerol concentration is not controlled by clearance in healthy humans, it has been proposed that elevated plasma free fatty acid (FFA) and glycerol concentrations in cirrhotic subjects are caused by accelerated lipolysis. This proposal has not been validated. We infused 10 volunteers, 10 cirrhotic subjects, and 10 patients after orthotopic liver transplantation (OLT) with [1-(13)C]palmitate and [(2)H(5)]glycerol to compare fluxes (R(a)) and FFA oxidation. Cirrhotic subjects had higher plasma palmitate (52%) and glycerol (33%) concentrations than controls. Palmitate R(a) was faster (1.45+/-0.18 vs. 0.85+/-0.17 micromol x kg(-1) x min(-1)) but glycerol R(a) and clearance slower (1.20+/-0.09 vs. 1.90+/-0.24 micromol x kg(-1) x min(-1) and 21.2+/-1.2 vs. 44.7+/- 4.9 ml x kg(-) x h(-1), respectively) than in controls. After OLT, plasma palmitate and glycerol concentrations and palmitate R(a) did not differ, but glycerol R(a) (1.16+/-0.11 micromol x kg(-1) x min(-1)) and clearance (26.7+/-2.4 ml x kg(-1) x h(-1)) were slower than in controls. We conclude that 1) impaired reesterification, not accelerated lipolysis, elevates FFA in cirrhotic subjects; 2) normalized FFA after OLT masks impaired reesterification; and 3) plasma glycerol concentration poorly reflects lipolytic rate in cirrhosis and after OLT.
Collapse
Affiliation(s)
- R E Shangraw
- Department of Anesthesiology, Oregon Health Sciences University and Veterans Affairs Medical Center, Portland, Oregon 97201, USA.
| | | |
Collapse
|