scholarly journals Skeletal muscle fatty acid handling in insulin resistance : the effect of dietary fatty acids

2012 ◽  
Author(s):  
A. Jans
2012 ◽  
Vol 97 (1) ◽  
pp. 208-216 ◽  
Author(s):  
Joris Hoeks ◽  
Marco Mensink ◽  
Matthijs K. C. Hesselink ◽  
Kim Ekroos ◽  
Patrick Schrauwen

Context: Animal studies revealed that medium-chain fatty acids (MCFA), due to their metabolic characteristics, are not stored in skeletal muscle and may therefore not give rise to potentially hazardous lipid species impeding insulin signaling. Objective: We here hypothesized that infusion of medium-chain triacylglycerols (MCT) in healthy lean subjects does not lead to ectopic fat accumulation and hence does not result in lipid-induced insulin resistance. Design and Methods: Nine healthy lean male subjects underwent a 6-h hyperinsulinemic-euglycemic clamp with simultaneous infusion of 1) a 100% long-chain triacylglycerols (LCT) emulsion, 2) a 50/50% MCT/LCT emulsion, or 3) glycerol in a randomized crossover design. Muscle biopsies were taken before and after each clamp. Results: MCT/LCT infusion raised plasma free fatty acid levels to a similar level compared with LCT infusion alone. Despite elevated free fatty acid levels, intramyocellular triacylglycerol (IMTG) levels were not affected by the MCT/LCT emulsion, whereas LCT infusion resulted in an approximately 1.6-fold increase in IMTG. These differences in muscle fat accumulation did not result in significant differences in lipid-induced insulin resistance between LCT (−28%, P = 0.003) and MCT/LCT (−20%, P < 0.001). Total skeletal muscle ceramide content as well as lactosyl- and glucosylceramide levels were not affected by any of the interventions. In addition, the distribution pattern of all ceramide species remained unaltered. Conclusions: Although we confirm that MCFA do not lead to ceramide and IMTG accumulation in skeletal muscle tissue in humans, they do induce insulin resistance. These results indicate that, in humans, MCFA may not be beneficial in preventing peripheral insulin resistance.


Endocrinology ◽  
2011 ◽  
Vol 152 (6) ◽  
pp. 2206-2218 ◽  
Author(s):  
Gong Peng ◽  
Linghai Li ◽  
Yanbo Liu ◽  
Jing Pu ◽  
Shuyan Zhang ◽  
...  

Pathological elevation of plasma fatty acids reduces insulin sensitivity. Although several regulation pathways have been reported, the molecular mechanisms of insulin sensitivity remain elusive, especially in skeletal muscle where most glucose is consumed. This study focuses on how two major dietary fatty acids affect insulin signaling in skeletal muscle cells. Palmitic acid (PA) not only reduced insulin-stimulated phosphorylation of Akt but also induced endoplasmic reticulum (ER) expansion and ER stress. Relieving ER stress using 4-phenyl butyric acid blocked PA-mediated protein kinase R-like ER kinase phosphorylation and ER expansion and reversed the inhibitory effect of PA on insulin-stimulated Akt phosphorylation. Importantly, oleic acid (OA) could also recover PA-reduced Akt phosphorylation and abolish both PA-mediated ER expansion and ER stress. The competition between these two fatty acids was further verified in rat skeletal muscle using venous fatty acid infusion. 3H-labeled PA was converted mainly to active lipids (phospholipids and diacylglycerol) in the absence of OA, but to triacylglycerol in the presence of OA. Subcellular triacylglycerol and adipocyte differentiation-related protein from PA-treated cells cofractionated with the ER in the absence of OA but switched to the low-density fraction in the presence of OA. Taken together, these data suggest that the PA-mediated lipid composition and localization may cause ER expansion and consequently cause ER stress and insulin resistance in skeletal muscle.


2021 ◽  
Author(s):  
Norihiro Imai ◽  
Hayley T. Nicholls ◽  
Michele Alves-Bezerra ◽  
Yingxia Li ◽  
Anna A. Ivanova ◽  
...  

ABSTRACTThioesterase superfamily member 2 (Them2) is highly expressed in oxidative tissues where it hydrolyzes long chain fatty acyl-CoA esters to free fatty acids and CoA. Although mice globally lacking Them2 (Them2-/-) are protected against diet-induced obesity, insulin resistance and hepatic steatosis, liver-specific Them2-/- mice remain susceptible. To explore the contribution of Them2 in extrahepatic tissues, we created mice with Them2 deleted in skeletal muscle (S-Them2-/-), cardiac muscle (C-Them2-/-) or adipose tissue (A-Them2-/-). When fed a high-fat diet, S-Them2-/- but not C-Them2-/- or A-Them2-/- mice exhibited reduced weight gain. Only S-Them2-/- mice exhibited improved glucose homeostasis together with improved insulin sensitivity in skeletal muscle. Increased rates of fatty acid oxidation in skeletal muscle of S-Them2-/- mice were reflected in alterations in skeletal muscle metabolites, including short chain fatty acids, branched chain amino acids and the pentose phosphate pathway. Protection from diet-induced hepatic steatosis in S-Them2-/- mice was attributable to increased VLDL triglyceride secretion rates in support of demands of increased muscle fatty acid utilization. These results reveal a key role for skeletal muscle Them2 in the pathogenesis of diet-induced obesity, insulin resistance and hepatic steatosis.


2016 ◽  
Vol 19 (4) ◽  
pp. 286-294 ◽  
Author(s):  
Vladimir Nicolaevich Titov ◽  
Vladimir Pavlovich Shirinsky

A biological function of the phylogenetically late humoral mediator insulin is to provide energy substrates for locomotion, i.e. movement resulting from contraction of striated muscles. Insulin is able to meet this evolutionary demand of an organism by means of the effective ATP production in the mitochondria. Exogenous fatty acids, optimised endogenous fatty acids produced from glucose and glucose itself are the major substrates for ATP synthesis. Cells stimulated by insulin produce ω-9 С18:1 oleic acid from glucose. This fatty acid is oxidised by the mitochondria at a higher rate than exogenous and endogenous C16:0 palmitic fatty acid. In the normal state of insulin system and mitochondria, the frequent cause of insulin resistance is the non-optimal properties of dietary fatty acids supplied for oxidation by the mitochondria. Dietary excess of saturated palmitic fatty acid over monogenic oleic fatty acid causes insulin resistance to develop. Insulin resistance syndrome is the condition of in vivo energy deficiency and insufficient production of ATP for the realisation of the biological adaptation and compensation. Insulin effectively inhibits lipolysis only in phylogenetically late subcutaneous adipocytes but not in phylogenetically early visceral fat cells of the omentum. Discrepancy in the regulation of energy substrate metabolism against the background of a ‘relative biological perfection’ of higher mammals is the aetiological basis of insulin resistance.


2000 ◽  
Vol 83 (S1) ◽  
pp. S91-S96 ◽  
Author(s):  
Bengt Vessby

A high intake of fat may increase the risk of obesity. Obesity, especially abdominal obesity, is an important determinant of the risk of developing insulin resistance and non-insulin-dependent diabetes mellitus. It is suggested that a high proportion of fat in the diet is associated with impaired insulin sensitivity and an increased risk of developing diabetes, independent of obesity and body fat localization, and that this risk may be influenced by the type of fatty acids in the diet. Cross-sectional studies show significant relationships between the serum lipid fatty acid composition, which at least partly mirrors the quality of the fatty acids in the diet, and insulin sensitivity. Insulin resistance, and disorders characterized by insulin resistance, are associated with a specific fatty acid pattern of the serum lipids with increased proportions of palmitic (16 : 0) and palmitoleic acids (16 : 1 n-7) and reduced levels of linoleic acid (18 : 2 n-6). The metabolism of linoleic acid seems to be disturbed with increased proportions of dihomo-gamma linolenic acid (20 : 3 n-6) and a reduced activity of the Δ5 desaturase, while the activities of the Δ9 and Δ6 desaturases appear to be increased. The skeletal muscle is the main determinant of insulin sensitivity. Several studies have shown that the fatty acid composition of the phosholipids of the skeletal muscle cell membranes is closely related to insulin sensitivity. An increased saturation of the membrane fatty acids and a reduced activity of Δ5 desaturase have been associated with insulin resistance. There are several possible mechanisms which could explain this relationship. The fatty acid composition of the lipids in serum and muscle is influenced by diet, but also by the degree of physical activity, genetic disposition, and possibly fetal undernutrition. However, controlled dietary intervention studies in humans investigating the effects of different types of fatty acids on insulin sensitivity have so far been negative.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ban-Hock Khor ◽  
◽  
Sharmela Sahathevan ◽  
Ayesha Sualeheen ◽  
Mohammad Syafiq Md Ali ◽  
...  

AbstractThe metabolic impact of circulating fatty acids (FAs) in patients requiring hemodialysis (HD) is unknown. We investigated the associations between plasma triglyceride (TG) FAs and markers of inflammation, insulin resistance, nutritional status and body composition. Plasma TG-FAs were measured using gas chromatography in 341 patients on HD (age = 55.2 ± 14.0 years and 54.3% males). Cross-sectional associations of TG-FAs with 13 markers were examined using multivariate linear regression adjusted for potential confounders. Higher levels of TG saturated fatty acids were associated with greater body mass index (BMI, r = 0.230), waist circumference (r = 0.203), triceps skinfold (r = 0.197), fat tissue index (r = 0.150), serum insulin (r = 0.280), and homeostatic model assessment of insulin resistance (r = 0.276), but lower malnutrition inflammation score (MIS, r =  − 0.160). Greater TG monounsaturated fatty acid levels were associated with lower lean tissue index (r =  − 0.197) and serum albumin (r =  − 0.188), but higher MIS (r = 0.176). Higher levels of TG n-3 polyunsaturated fatty acids (PUFAs) were associated with lower MIS (r =  − 0.168) and interleukin-6 concentrations (r =  − 0.115). Higher levels of TG n-6 PUFAs were associated with lower BMI (r =  − 0.149) but greater serum albumin (r = 0.112). In conclusion, TG monounsaturated fatty acids were associated with poor nutritional status, while TG n-3 PUFAs were associated with good nutritional status. On the other hand, TG saturated fatty acids and TG n-6 PUFAs had both favorable and unfavorable associations with nutritional parameters.


2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1038-1038
Author(s):  
Michael Miklus ◽  
Pedro Prieto ◽  
Cynthia Barber ◽  
Robert Rhoads ◽  
Samer El-Kadi

Abstract Objectives The objectives of this study were to determine the effect of 2’fucosyllactose (2’FL) and fat blends on growth, body composition and fatty acid profile of the liver and brain using the neonatal pig as a model for the human infant. Methods Pigs (3 d old) were randomly assigned to either: 1. control, 2. Palm Olein (PO) fat blend – Low 2'-FL, 3. PO – High 2'-FL, 4. High oleic acid (HO) – Low 2'-FL, 5. HO FB – High 2'-FL, 6. PO FB – GLA, or 7. kept with their sows. Pigs in groups 1 to 6 received 250 ml·kg−1·d−1 of formula in 5 equal meals for 15 d. On day 14 of the study, groups 1–6 received intraperitoneal E. coli LPS challenge at 100 µg·kg−1 weight. Results Body weight was greater for piglets fed by sows than those in the other groups (P < 0.001). In addition, % fat and bone mineral content were higher in the sow-fed group while lean % was less sow-fed piglets (group 7) compared with those in the other groups (P < 0.05). Only longissimus weight expressed as a % of body weight, was greater for group 7 compared with all other groups (P < 0.001). Soleus, semitendinosus, brain, heart and spleen weights as a % of body weight were similar across all groups. However, liver weight as a % of body weight was greater in groups 1–6 (3.7%) compared with group 7 (2.8%; P < 0.001). The proportion of brain 16:1 fatty acid was less (0.83%) for groups 1–6 than for group 7 pigs (1.08%; P < 0.0001). The proportion of 20:3 N6 was greatest (0.66%) for group 3 compared with groups 1 and 4 (0.55%; P < 0.05). In addition, the proportion of 20:5 N3 was greatest (0.12%) for group 3 compared with groups 1 and 7 (0.07%; P < 0.05). The proportion of liver 16:1, 18:0, and 18:1 cis-11 fatty acids were greater for group 7 (2.3, 23, 2.2%) than groups 1–6 (0.2, 20, 1.2%; P < 0.0001). Conversely, the contribution of 14:0, 18:1 cis-9, 18:3 N6 cis-6,9,12, and 22:6 N3 were greater for pigs in groups 1–6 (1.3, 0.6, and 14, 7.8%) compared with those in group 7 (0.5, 8.5, 0.2 and 3.5%; P < 0.0001). Conclusions Our data suggest that feeding 2’fucosyllactose had no effect on the body weight gain and composition in neonatal pigs. Our data also suggest that dietary fatty acids have a greater effect on liver than on brain fatty acid composition. Funding Sources Funding for the work was provided by Perrigo Nutritionals, LLC.


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