Rapid measurement of plasma free fatty acid concentration and isotopic enrichment using LC/MS

Persson, Xuan Mai T.; Błachnio-Zabielska, Agnieszka; Jensen, Michael D.

doi:10.1194/jlr.m008011

Cited by 119 publications

(95 citation statements)

References 20 publications

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“…Plasma free fatty acid concentrations were measured by liquid chromatography/mass spectrometry (LC/MS), as described previously (51). Briefly, 50 l of plasma was spiked with heptadecanoate internal standard (ISTD) and analyzed with Applied Biosystems (Foster City, CA) API5000 mass spectrometer coupled with a Cohesive (Franklin, MA) TX2 liquid chromatography system.…”

Section: Methodsmentioning

confidence: 99%

Impact of insulin deprivation and treatment on sphingolipid distribution in different muscle subcellular compartments of streptozotocin-diabetic C57Bl/6 mice

Zabielski

Błachnio-Zabielska

Lanza

et al. 2014

American Journal of Physiology-Endocrinology and Metabolism

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Insulin deprivation in type 1 diabetes (T1D) individuals increases lipolysis and plasma free fatty acids (FFA) concentration, which can stimulate synthesis of intramyocellular bioactive lipids such as ceramides (Cer) and longchain fatty acid-CoAs (LCFa-CoAs). Ceramide was shown to decrease muscle insulin sensitivity, and at mitochondrial levels it stimulates reactive oxygen species production. Here, we show that insulin deprivation in streptozotocin diabetic C57BL/6 mice increases quadriceps muscle Cer content, which was correlated with a concomitant decrease in the body fat and increased plasma FFA, glycosylated hemoglobin level (%Hb A 1c), and muscular LCFa-CoA content. The alternations were accompanied by an increase in protein expression in LCFa-CoA and Cer synthesis (FATP1/ACSVL5, CerS1, CerS5), a decrease in the expression of genes implicated in muscle insulin sensitivity (GLUT4, GYS1), and inhibition of insulin signaling cascade by Akt␣ and GYS3␤ phosphorylation under acute insulin stimulation. Both the content and composition of sarcoplasmic fraction sphingolipids were most affected by insulin deprivation, whereas mitochondrial fraction sphingolipids remained stable. The observed effects of insulin deprivation were reversed, except for content and composition of LCFa-CoA, CerS protein expression, GYS1 gene expression, and phosphorylation status of Akt and GYS3␤ when exogenous insulin was provided by subcutaneous insulin implants. Principal component analysis and Pearson's correlation analysis revealed close relationships between the features of the diabetic phenotype, the content of LCFa-CoAs and Cers containing C18-fatty acids in sarcoplasm, but not in mitochondria. Insulin replacement did not completely rescue the phenotype, especially regarding the content of LCFa-CoA, or proteins implicated in Cer synthesis and muscle insulin sensitivity. These persistent changes might contribute to muscle insulin resistance observed in T1D individuals. type 1 diabetes; skeletal muscle; mitochondria; ceramide; long-chain fatty acid-coenzyme A METICULOUS GLYCEMIC CONTROL in type 1 diabetic (T1D) individuals can be achieved by administration of prandial, shortacting, and long-acting insulin to mimic ␤-cell secretion in response to varying nutrient levels. Metabolic control in these individuals and stringent adherence to guidelines normalize the plasma glucose and glycosylated hemoglobin levels (%Hb A 1c ) and allow for relatively normal life in T1D. Yet T1D individuals are at greater risk of developing cardiovascular disorders and also known to develop insulin resistance (12, 17). The molecular mechanisms responsible for insulin resistance in T1D subjects are unclear, but variable glucose concentrations (28, 70), advanced glycation end products (62, 73), or desensitization of target tissues by insulin (61) have been proposed. Subcutaneous insulin delivery using an insulin pump partially mimics ␤-cell insulin secretion. However, unlike in nondiabetic individuals with twofold higher hepatic insulin concentration than in ...

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Section: Methodsmentioning

confidence: 99%

Impact of insulin deprivation and treatment on sphingolipid distribution in different muscle subcellular compartments of streptozotocin-diabetic C57Bl/6 mice

Zabielski

Błachnio-Zabielska

Lanza

et al. 2014

American Journal of Physiology-Endocrinology and Metabolism

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“…The fractions were hydrolyzed together with the respective standard curves into FFAs prior to LC-MS analysis (36). Total TAG and total DAG were considered the sum of the following components in each fraction: myristic acid ( Ceramides (7) were quantified by ultraperformance liquid chromatography/tandem mass spectrometry (UPLC/MS-MS), as described previously.…”

Section: Methodsmentioning

confidence: 99%

Training status diverges muscle diacylglycerol accumulation during free fatty acid elevation

Chow

Mashek

Austin

et al. 2014

American Journal of Physiology-Endocrinology and Metabolism

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How endurance training alters muscle lipid metabolism while preserving insulin sensitivity remains unclear. Because acute free fatty acid (FFA) elevation by lipid infusion reduces insulin sensitivity, we hypothesized that training status would alter accumulation of muscle triacylglycerol (TAG), diacylglycerol (DAG), ceramide, and acylcarnitine during acute FFA elevation. Trained (n ϭ 15) and sedentary (n ϭ 13) participants matched for age, sex, and BMI received either a 6-h infusion of lipid (20% Intralipid at 90 ml/h) or glycerol (2.25 g/100 ml at 90 ml/h) during a hyperinsulinemic euglycemic clamp. Muscle biopsies were taken at 0, 120, and 360 min after infusion initiation to measure intramyocellular concentrations of TAG, DAG, ceramides, and acylcarnitines by liquid chromatography-tandem mass spectrometry. Trained participants had a higher V O2 max and insulin sensitivity than sedentary participants. The lipid infusion produced a comparable elevation of FFA (594 Ϯ 90 mol/l in trained, 721 Ϯ 30 mol/l in sedentary, P ϭ 0.4) and a decline in insulin sensitivity (Ϫ44.7% trained vs. Ϫ47.2% sedentary, P ϭ 0.89). In both groups, lipid infusion increased the linoleic and linolenic acid content of TAG without changing total TAG. In the sedentary group, lipid infusion increased total, oleic, and linoleic acid and linolenic acid content of DAG. Regardless of training status, lipid infusion did not alter total ceramide, saturated ceramide, palmitoyl-carnitine, or oleoyl-carnitine. We conclude that during acute FFA elevation, trained adults have a similar decline in insulin sensitivity with less accumulation of muscle DAG than sedentary adults, suggesting that lipid-induced insulin resistance can occur without elevation of total muscle DAG.training; intramyocellular lipid; diacylglycerol; insulin sensitivity; free fatty acids INSULIN RESISTANCE IS A CRITICAL CONTRIBUTOR to type 2 diabetes mellitus (T2DM), a disease that adversely affects millions of Americans. Insulin resistance has a well-established association with the metabolic syndrome (15) and predates T2DM (32). Because skeletal muscle is the largest site of insulin resistance (16,43), there is intense interest in understanding the mechanism of insulin resistance in these tissues.In sedentary humans, muscle insulin resistance has been attributed to lipotoxicity, which is defined as the elevation of lipids and/or lipid metabolites within blood or tissues with subsequent metabolic derangement. Several lines of evidence support this theory. Despite hyperinsulinemia, free fatty acid (FFA) levels are roughly two times higher in humans with obesity (2), insulin resistance (2), or T2DM (39) than in healthy humans. FFA elevation, in turn, increases intramyocellular lipid (IMCL) levels (10), a measurement that in sedentary humans is inversely associated with insulin sensitivity (30, 35). Although FFA elevation was initially thought to increase muscle insulin resistance by increasing IMCL (10), subsequent work has suggested that lipid metabolites such as diacylglycerol (DAG)...

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“…Plasma palmitate concentration and isotopic enrichment in both the infusate and plasma samples was measured according to Persson et al [16]. Isotope tracer infusion and lipid FSR calculation was performed according to Blachnio-Zabielska et al [19].…”

Section: Isotope Infusion Tissue Collection and Lipid Fractional Synmentioning

confidence: 99%

The Crucial Role of C18-Cer in Fat-Induced Skeletal Muscle Insulin Resistance

Błachnio-Zabielska

Chacińska

Vendelbo

et al. 2016

Cell Physiol Biochem

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Background/Aims: Muscle bioactive lipids accumulation leads to several disorder states. The most common are insulin resistance (IR) and type 2 diabetes. There is an ongoing debate which of the lipid species plays the major role in induction of muscle IR. Our aim was to elucidate the role of particular lipid group in induction of muscle IR. Methods: The analyses were performed on muscle from the following groups of rats: 1. Control, fed standard diet, 2 HFD, fed high fat diet, 3. HFD/Myr, fed HFD and treated with myriocin (Myr), an inhibitor of ceramide de novo synthesis. We utilized [U¹³C] palmitate isotope tracer infusion and mass spectrometry to measure content and synthesis rate of muscle long-chain acyl-CoA (LCACoA), diacylglycerols (DAG) and ceramide (Cer). Results: HFD led to intramuscular accumulation of LCACoA, DAG and Cer and skeletal muscle IR. Myr-treatment caused decrease in Cer (most noticeable for stearoyl-Cer and oleoyl-Cer) and accumulation of DAG, possibly due to re-channeling of excess of intramuscular LCACoA towards DAG synthesis. An improvement in insulin sensitivity at both systemic and muscular level coincided with decrease in ceramide, despite elevated intramuscular DAG. Conclusion: The improved insulin sensitivity was associated with decreased muscle stearoyl- and oleoyl-ceramide content. The results indicate that accumulation of those ceramide species has the greatest impact on skeletal muscle insulin sensitivity in rats.

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Rapid measurement of plasma free fatty acid concentration and isotopic enrichment using LC/MS

Cited by 119 publications

References 20 publications

Impact of insulin deprivation and treatment on sphingolipid distribution in different muscle subcellular compartments of streptozotocin-diabetic C57Bl/6 mice

Impact of insulin deprivation and treatment on sphingolipid distribution in different muscle subcellular compartments of streptozotocin-diabetic C57Bl/6 mice

Training status diverges muscle diacylglycerol accumulation during free fatty acid elevation

The Crucial Role of C18-Cer in Fat-Induced Skeletal Muscle Insulin Resistance

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