Effect of short-term exercise training on intramyocellular lipid content

Aryl Hydrocarbon Receptor Nuclear Translocator/ hypoxia-inducible factor 1 beta (ARNT/ HIF1β), a member of bHLH-PAS family of transcriptional factors, plays a critical role in metabolic homeostasis, insulin resistance and glucose intolerance. The contributions of ARNT in pancreas, liver and adipose tissue to energy balance through gene regulation have been described. Surprisingly, the impact of ARNT signaling in the skeletal muscles, one of the major organs involved in glucose disposal, has not been investigated, especially in type II diabetes. Here we report that ARNT is expressed in the skeletal muscles, particularly in the energy-efficient oxidative slow-twitch myofibers, which are characterized by increased oxidative capacity, mitochondrial content, vascular supply and insulin sensitivity. However, muscle-specific deletion of ARNT did not change myofiber type distribution, oxidative capacity, mitochondrial content, capillarity, or the expression of genes associated with these features. Consequently, the lack of ARNT in the skeletal muscle did not affect weight gain, lean/fat mass, insulin sensitivity and glucose tolerance in lean mice, nor did it impact insulin resistance and glucose intolerance in high fat diet-induced obesity. Therefore, skeletal muscle ARNT is dispensable for controlling muscle fiber type and metabolic regulation, as well as diet-induced weight control, insulin sensitivity and glucose tolerance.

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“…SDH and NADH-TR staining was performed on cryosections (10 μm thickness) of TA muscles, as previously described [21,22]. …”

Section: Methodsmentioning

confidence: 99%

Muscle Arnt/Hif1β Is Dispensable in Myofiber Type Determination, Vascularization and Insulin Sensitivity

et al. 2016

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“…They did not report the medication used, but states that medication was stopped three days prior to the test days, indicating that the patients were on medication during the training period, and in addition an appropriate control group was not investigated. Another group investigated lean, obese and patients with type 2 diabetes before and after 10 d of 60 min exercise at 70% of VO2peak [32] . No differences were seen in muscle oxidative capacity between groups before and after training, which is quite intriguing taking into consideration that the lean subjects had a higher maximal oxygen uptake (approximately 50%) compared with the two other groups.…”

Section: Muscular Adaptation To Different Training Modalities In Patimentioning

confidence: 99%

“…No differences were seen in muscle oxidative capacity between groups before and after training, which is quite intriguing taking into consideration that the lean subjects had a higher maximal oxygen uptake (approximately 50%) compared with the two other groups. Insulin sensitivity was unfortunately not measured [32] . Mitochondrial volume (by TEM) was investigated after 10 wk of endurance training (approximately 70% of VO2max) and a similar increase in mitochondrial volume was seen in patients with type 2 diabetes and control participants, accompanied by improvements in maximal oxygen uptake and insulin sensitivity (clamp) [84] .…”

Section: Muscular Adaptation To Different Training Modalities In Patimentioning

confidence: 99%

“…Two weeks of HIT has been reported to increase mitochondrial content (CS activity) and improve 24 h blood glucose profile (measured 48-72 h after last training [81] T2DM and CON ET 10 wk (2-3 times/wk) ↑ T2DM ↑ T2DM ↑ T2DM ↑ CON ↑ CON ↑ CON Hey-Mogensen et al [8] T2DM and CON ET 10 wk (4-5 times/wk) ↑ T2DM ↑ T2DM ↑ T2DM ↑ CON ↑ CON ↑ CON Phielix et al [17] T2DM and CON ET and ST 12 wk (3 times/wk) ↑ T2DM ↑ T2DM ↑ T2DM → CON ↑ CON → CON Meex et al [27] T2DM and CON ET and ST 12 wk (3 times/wk) ↑ T2DM ↑ T2DM ↑ T2DM ↑ CON ↑ CON → CON Shaw et al [83] T2DM ET 6 mo (3 times/wk) ↑ T2DM ↑ T2DM → T2DM Sparks et al [31] T2DM and ET 9 mo (150 min/wk) → T2DM → T2DM → T2DM Bajpeyi et al [32] T2DM and CON (L and O) ET 10 d (every day) ND → T2DM ND → CON (L and O) Nielsen et al [84] T2DM and CON ET 10 wk ( bout) [85] in patients with type 2 diabetes. Unfortunately no control group was included by Little and colleagues [85] , but in another study a similar improvement in CS activity was observed in overweight women using the same training protocol [86] .…”

Section: High Intensity Trainingmentioning

confidence: 99%

“…It has been suggested that insulin resistant people may have an attenuated response to exercise training, compared with healthy control subjects [28] . Furthermore it has been reported that the response to an acute bout of exercise is attenuated in insulin-resistant compared with lean control subjects [29] , when investigating genes coding for mitochondrial biogenesis (PGC-1α mRNA and protein abundance), which could explain the lack of a training effect in patients with type 2 diabetes in some studies [30][31][32] . It has been reported that different molecular signals in the skeletal muscle are responsible for the activation of mitochondrial biogenesis after exercise.…”

Section: Introductionmentioning

confidence: 99%

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Effects of exercise training on mitochondrial function in patients with type 2 diabetes

Larsen

Skaaby

Helge

et al. 2014

WJD

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Core tip: It is well described that exercise interventions improves insulin sensitivity and maximal oxygen uptake in patients with type 2 diabetes as well as in control subjects. When it comes to adaptations in mitochondrial function after an exercise intervention the literature is more sparse especially in patients with type 2 diabetes. Furthermore the medication that patients with type 2 diabetes are using, are often not described well in the papers, and it is known that the different medication (statins and antihypertensive agents) have a major effect on mitochondrial function and insulin sensitivity.Larsen S, Skaaby S, Helge JW, Dela F. Effects of exercise training on mitochondrial function in patients with type 2 diabetes.

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Lipid in skeletal muscle myotubes is associated to the donors' insulin sensitivity and physical activity phenotypes

Bajpeyi

Myrland

Covington

et al. 2013

Obesity

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Objective This study investigated the relationship between in-vitro lipid content in myotubes and in-vivo whole body phenotypes of the donors such as insulin sensitivity, intramyocellular lipids (IMCL), physical activity and oxidative capacity. Design and Methods Six physically active donors were compared to 6 sedentary lean and 6 T2DM. Lipid content was measured in tissues and myotubes by immunohistochemistry. Ceramides, triacylglycerols (TAGs) and diacylglycerols (DAGs) were measured by LC-MS-MS and GC-FID. Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp (80mU/min/m2), maximal mitochondrial capacity (ATPmax) by 31P-MRS, physical fitness by VO2max and physical activity level (PAL) by accelerometers. Results Myotubes cultured from physically active donors had higher lipid content (0.047±0.003 vs. 0.032±0.001 and 0.033±0.001AU; p<0.001) than myotubes from lean and T2DM donors. Lipid content in myotubes was not associated with IMCL in muscle tissue but importantly, correlated with in-vivo measures of ATPmax (r=0.74; p<0.001), insulin sensitivity (r=0.54; p<0.05), type-I fibers (r=0.50; p<0.05) and PAL (r=0.92; p<0.0001). DAGs and ceramides in myotubes were inversely associated with insulin sensitivity (r=−0.55, r=−0.73; p<0.05) and ATPmax (r=−0.74, r=−0.85; p<0.01). Conclusions These results indicate that cultured human myotubes can be used in mechanistic studies to study the in vitro impact of interventions on phenotypes such as mitochondrial capacity, insulin sensitivity, and physical activity.

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Effect of short-term exercise training on intramyocellular lipid content

Cited by 21 publications

References 34 publications

Muscle Arnt/Hif1β Is Dispensable in Myofiber Type Determination, Vascularization and Insulin Sensitivity

Muscle Arnt/Hif1β Is Dispensable in Myofiber Type Determination, Vascularization and Insulin Sensitivity

Effects of exercise training on mitochondrial function in patients with type 2 diabetes

Lipid in skeletal muscle myotubes is associated to the donors' insulin sensitivity and physical activity phenotypes

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