Utilisation of Intramyocellular Lipids (IMCLs) During Exercise as Assessed by Proton Magnetic Resonance Spectroscopy (1H-MRS)

Brechtel, Klaus; Nieß, Andreas M.; Machann, Juergen; Rett, K.; Schick, Fritz; Claussen, CD; Dickhuth, Hans-Hermann; Haering, Hans U.; Jacob, Stephan

doi:10.1055/s-2001-12407

Cited by 105 publications

(97 citation statements)

References 9 publications

(17 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Boesch et al (2) revealed a decrease of IMCL in one subject performing a mountain bike ride over 3 h at about 70% of VO 2max , for the first time using 1 H-MRS to demonstrate that IMCL are metabolized during this form of exercise. In the following years, numerous reports on reduced IMCL levels during exercise were published and reviewed (17,20,(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49). It became obvious that both exercise duration and intensity are important factors in determining the reduction of IMCL (39).…”

Section: Various Other Influences Upon Imcl Levelsmentioning

confidence: 99%

Role of proton MR for the study of muscle lipid metabolism

et al. 2006

View full text Add to dashboard Cite

1 H-MR spectroscopy (MRS) of intramyocellular lipids (IMCL) became particularly important when it was recognized that IMCL levels are related to insulin sensitivity. While this relation is rather complex and depends on the training status of the subjects, various other influences such as exercise and diet also influence IMCL concentrations. This may open insight into many metabolic interactions; however, it also requires careful planning of studies in order to control all these confounding influences. This review summarizes various historical, methodological, and practical aspects of 1 H-MR spectroscopy (MRS) of muscular lipids. That includes a differentiation of bulk magnetic susceptibility effects and residual dipolar coupling that can both be observed in MRS of skeletal muscle, yet affecting different metabolites in a specific way. Fitting of the intra-(IMCL) and extramyocellular (EMCL) signals with complex line shapes and the transformation into absolute concentrations is discussed. Since the determination of IMCL in muscle groups with oblique fiber orientation or in obese subjects is still difficult, potential improvement with high-resolution spectroscopic imaging or at higher field strength is considered. Fat selective imaging is presented as a possible alternative to MRS and the potential of multinuclear MRS is discussed. 1 H-MRS of muscle lipids allows non-invasive and repeated studies of muscle metabolism that lead to highly relevant findings in clinics and patho-physiology.

show abstract

Section: Various Other Influences Upon Imcl Levelsmentioning

confidence: 99%

Role of proton MR for the study of muscle lipid metabolism

et al. 2006

View full text Add to dashboard Cite

show abstract

“…At an intensity of 80% VO 2 max glycogen stores will be emptied in about 90-180 min 31 and at this intensity, 80% of the energy derives from carbohydrate oxidation 32 of the muscle glycogen, whereas the oxidation of intramuscular triglycerides is inhibited. 33 At even higher intensities, muscle glycogen is oxidized anaerobically and the concentration of lactate will rise to values around 5 mmol/l. 34 The reason for inhibition of fat oxidation at higher intensities is given by the inhibition of mobilization of long-chain fatty acids from subcutaneous adipose tissue, 35 the limited entry of long-chain fatty acids into the mitochondria for oxidation 36 and the inhibition of the oxidation of intramuscular triglycerides.…”

Section: Fitness Levelmentioning

confidence: 99%

“…34 The reason for inhibition of fat oxidation at higher intensities is given by the inhibition of mobilization of long-chain fatty acids from subcutaneous adipose tissue, 35 the limited entry of long-chain fatty acids into the mitochondria for oxidation 36 and the inhibition of the oxidation of intramuscular triglycerides. 33 With increasing intensity, carbohydrate oxidation is increased, whereas fat oxidation is reduced 37 and lactate fails to be completely eliminated. 38 The elimination of lactate in SCI could be reduced compared to ablebodied persons due to differences in muscle mass and muscle fibre distribution.…”

Section: Fitness Levelmentioning

confidence: 99%

Optimal exercise intensities for fat metabolism in handbike cycling and cycling

2004

View full text Add to dashboard Cite

Study design: Energy expenditure (EE) and fat oxidation in handbike cycling compared to cycling in order to determine the intensity that elicits maximal fat oxidation in handbike cycling. Objective: To establish the exercise intensity with the highest fat oxidation rate in handbike cycling compared with cycling (control group) in order to give training recommendations for spinal cord-injured (SCI) athletes performing handbike cycling. Setting: Institute of Sports Medicine, Swiss Paraplegic Centre, Nottwil, Switzerland. Methods: Eight endurance-trained handbike cyclists (VO 2 peak handbike cycling 37.577.8 ml/kg/ min) and eight endurance trained cyclists (VO 2 peak cycling 62.574.5 ml/kg/min) performed three 20-min exercise blocks at 55, 65 and 75% VO 2 peak in handbike cycling on a treadmill or in cycling on a cycling ergometer, respectively, in order to find the intensity with the absolutely highest fat oxidation. Results: The contribution of fat to total EE was highest (39.1716.3% EE) at 55% VO 2 peak in handbike cycling compared to cycling, where highest contribution of fat to EE (50.8713.8%) was found at 75% VO 2 peak. In handbike cycling, the highest absolute fat oxidation (0.2870.10 g/min) was found at 55% VO 2 peak compared to cycling, where highest fat oxidation (0.6770.20 g/min) was found at 75% VO 2 peak. Conclusion: Well-trained handbike cyclists have their highest fat oxidation at 55% VO 2 peak handbike cycling compared to well-trained cyclists at 75% VO 2 peak cycling . Handbike cyclists should perform endurance exercise training at 55% VO 2 peak handbike cycling , whereas well-trained cyclists should be able to exercise at 75% VO 2 peak cycling . For training recommendations, the heart rate at 55% VO 2 peak handbike cycling lies at 13576 bpm in handbike cycling in SCI compared to 147714 bpm at 75% VO 2 peak cycling in well-trained cyclists. We presume that the reduced muscle mass involved in exercise during handbike cycling is the most important factor for impaired fat oxidation compared to cycling. But also other factors as fitness level and haemodynamic differences should be considered. Our results are only applicable to well-trained handbike cyclists with SCI and not for the general SCI population.

show abstract

“…A relatively rapid regulation is suggested by clinical studies showing that moderate prolonged exercise decreases IMCL within hours (12). However, which factors control the accumulation of IMCL and how rapidly this occurs is largely unknown.…”

mentioning

confidence: 99%

Effects of Intravenous and Dietary Lipid Challenge on Intramyocellular Lipid Content and the Relation With Insulin Sensitivity in Humans

et al. 2001

View full text Add to dashboard Cite

An increased intramyocellular lipid (IMCL) content, as quantified by 1 H-magnetic resonance spectroscopy ( 1 H-MRS), is associated with reduced insulin sensitivity. At present, it is unclear which factors determine IMCL formation and how rapidly IMCL accumulation can be induced. We therefore studied the impact of hyperinsulinemia and elevated circulating nonesterified fatty acid (NEFA) levels on IMCL formation and insulin sensitivity. We further evaluated the influence of a high-fat diet on IMCL storage. In the infusion protocol, 12 healthy male subjects underwent a 6-h hyperinsulinemic-euglycemic glucose clamp with concomitant infusion of Intralipid plus heparin. IMCL was quantified by 1 H-MRS in soleus (SOL) and tibialis anterior (TA) muscle at baseline and then every hour. IMCL levels started to increase significantly after 2 h, reaching a maximum of 120.8 ؎ 3.4% (SOL) and 164.2 ؎ 13.8% (TA) of baseline after 6 h (both P < 0.05). In parallel, the glucose infusion rate (GIR) decreased progressively, reaching a minimum of 60.4 ؎ 5.4% of baseline after 6 h. Over time, the GIR was strongly correlated with IMCL in TA (r ‫؍‬ ؊0.98, P < 0.003) and SOL muscle (r ‫؍‬ ؊0.97, P < 0.005). In the diet protocol, 12 male subjects ingested both a high-fat and low-fat diet for 3 days each. Before and after completion of each diet, IMCL levels and insulin sensitivity were assessed. After the high-fat diet, IMCL levels increased significantly in TA muscle (to 148.0 ؎ 16.9% of baseline; P ‫؍‬ 0.005), but not in SOL muscle (to 114.4 ؎ 8.2% of baseline; NS). Insulin sensitivity decreased to 83.3 ؎ 5.6% of baseline (P ‫؍‬ 0.033). There were no significant changes in insulin sensitivity or IMCL levels after the low-fat diet. The effects of the high-fat diet showed greater interindividual variation than those of the infusion protocol. The data from the lipid infusion protocol suggest a functional relationship between IMCL levels and insulin sensitivity. Similar effects could be induced by a high-fat diet, thereby underlining the physiological relevance of these observations.

show abstract

Utilisation of Intramyocellular Lipids (IMCLs) During Exercise as Assessed by Proton Magnetic Resonance Spectroscopy (1H-MRS)

Cited by 105 publications

References 9 publications

Role of proton MR for the study of muscle lipid metabolism

Role of proton MR for the study of muscle lipid metabolism

Optimal exercise intensities for fat metabolism in handbike cycling and cycling

Effects of Intravenous and Dietary Lipid Challenge on Intramyocellular Lipid Content and the Relation With Insulin Sensitivity in Humans

Contact Info

Product

Resources

About