Creatine, Potassium and Phosphorus Content of Cardiac and Voluntary Muscle.

Mangun, George H.; Myers, Victor C.

doi:10.3181/00379727-35-9015p

Cited by 9 publications

(5 citation statements)

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“…These values are smaller than previous estimates of 28 ± 6 μmol/g (2) and 28.9 ± 4.4 μmol/g wet weight (9) possibly reflecting uncertainties in the relaxation corrections, differences between time and frequency domain spectral analysis and partial contamination of the CR signal if the TMA resonance at 3.2 ppm is not fitted independently. However, when comparing the data of this work against biochemical analysis of CR concentrations [17.9 μmol/g (31) and 20.8 ± 4.5 μmol/g (32)] very good correspondence is noted. Likewise, when comparing the data with 31 P measurement results with phosphocreatine concentration found at 9 ± 1.2 μmol/g wet weight (33) and assuming a flux ratio of Cr to phosphocreatine of 0.81, as derived from isolated perfused rat hearts (34), a CR concentration of 16.3 μmol/g wet weight is found in reasonable agreement with the results of this study.…”

Section: Discussionmentioning

confidence: 57%

Metabolic MR imaging of regional triglyceride and creatine content in the human heart

Weiss

Mondaini

Boesiger

et al. 2012

Magnetic Resonance in Med

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An optimized echo-planar spectroscopic imaging sequence is proposed to facilitate spatial mapping of triglyceride and total creatine content in the human heart. The sequence integrates local-look field of view reduction, cardiac and respiratory gating, and dedicated reconstruction steps to account for gradient channel delays, field inhomogeneity, and phase incoherence due to residual motion. The technique is demonstrated in 12 volunteers in comparison to single voxel point-resolved spectroscopy in the septal wall at 1.5 T. Triglyceride-to-water and total creatine-to-water ratios derived from echo-planar spectroscopic imaging (0.48 ± 0.18% and 0.06 ± 0.03%) and point-resolved spectroscopy (0.52 ± 0.17% and 0.07 ± 0.02%) were found to agree well. In the septal region, intraclass correlation coefficients ranging from 0.67 to 0.72 were estimated. A relatively weak agreement (intraclass correlation coefficients: 0.34 and 0.52) was found for sectors in the lateral wall due to field gradients induced by the posterior vein and limited sensitivity of the receive coil array in this area. On the basis of the findings, it is concluded that fast spectroscopic imaging of both cardiac triglyceride and total creatine content is feasible. Shimming and sensitivity challenges in the lateral region remain, however, to be addressed.

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Section: Discussionmentioning

confidence: 57%

Metabolic MR imaging of regional triglyceride and creatine content in the human heart

Weiss

Mondaini

Boesiger

et al. 2012

Magnetic Resonance in Med

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“…A further consideration, given the nature of their sport and specific training undertaken, the population of kayak athletes used in this study had a larger than average proportion of their SMM on their upper body. This might also have implications for the D 3 ‐cr technique given that different muscle groups have also been shown to have distinct concentrations of creatine (eg, pectorals were found to have 4.62 g/kg, abdominals 3.96 g/kg, legs 3.91, and psoas 3.89 g/kg). The vast majority of creatine in the body is in skeletal muscle, and variations in creatine content among muscle groups are due mainly to fiber type composition (eg, Brault and Terjung, 2003).…”

Section: Discussionmentioning

confidence: 99%

“…The D 3 -cr technique has the potential to be a more convenient and cost-effective tool than other methods currently available for the measurement of SMM. 11,28 However, a more complex model reflecting the global intramuscular creatine pool may be required for accuracy in populations of more extreme variation in muscle fiber type composition, such as highly trained athletes. Such a model would need to account for the variability in intramuscular creatine pool between groups of individuals, reflecting differences in fiber distribution as well as diet.…”

Section: Discussionmentioning

confidence: 99%

“…The D 3 ‐cr technique has the potential to be a more convenient and cost‐effective tool than other methods currently available for the measurement of SMM . However, a more complex model reflecting the global intramuscular creatine pool may be required for accuracy in populations of more extreme variation in muscle fiber type composition, such as highly trained athletes.…”

Section: Discussionmentioning

confidence: 99%

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Total body skeletal muscle mass estimated by magnetic resonance imaging and creatine (methyl‐d₃) dilution in athletes

Morris-Paterson

Stimpson

Miller

et al. 2019

Scandinavian Med Sci Sports

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Creatine dilution (D3‐cr) is a technique for estimating total skeletal muscle mass (SMM) with practical utility, but has not been applied in athletic populations where body composition may differ to that in the normal population. This study aimed to assess the agreement between SMM derived from both D3‐cr and that obtained from whole‐body magnetic resonance imaging (MRI) in 15 male and 5 female national level kayakers (stature: 182.0 ± 13.1 and 170.0 ± 9.0 cm; body mass: 80.6 ± 9.9 and 66.4 ± 6.0 kg; V̇O2peak: 56.5 ± 7.0 and 49.6 ± 4.4 mL kg−1 min−1, mean ± SD). SMM was determined following 60 mg of dosed D3‐cr and analysis of expelled urine collected on four subsequent days for creatine, creatinine, D3‐cr, and D3‐creatinine using liquid chromatography/mass spectroscopy. SMM was then estimated by assuming a creatine pool size of 4.3 g/kg. During the same time period, a whole‐body MRI was undertaken to derive SMM from the analysis of multiple slices taken across the body. A strong positive correlation (F = 74.32; R = 0.90; P < .0001) between the two methods was observed, but the D3‐cr SMM was found to be significantly higher (43.3 ± 6.8 kg) when compared with MRI (36.3 ± 5.8 kg, P < .0001). However, the difference between the methods was removed when a higher intramuscular creatine pool (5.1 g/kg) was assumed. These data show that D3‐cr has potential utility in athletes, as referenced against MRI, but show that assumptions regarding creatine pool size need to be carefully considered.

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“…39 , 40 The combination of high creatine concentration and large mass makes skeletal muscle the largest contributor to the total creatine pool. Heart has a lower creatine concentration (~2 g/kg) 41 and a smaller mass (~0.24–0.33 kg). 39 Brain has a creatine concentration of ~1.2–1.8 g/kg 42 and a mass of about 1.2–1.4 kg.…”

Section: Creatine‐( Methyl ‐D 3 ...mentioning

confidence: 99%

D₃‐creatine dilution for skeletal muscle mass measurement: historical development and current status

McCarthy

Schoeller

Brown

et al. 2022

J cachexia sarcopenia muscle

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The French chemist Michel Eugène Chevreul discovered creatine in meat two centuries ago. Extensive biochemical and physiological studies of this organic molecule followed with confirmation that creatine is found within the cytoplasm and mitochondria of human skeletal muscles. Two groups of investigators exploited these relationships five decades ago by first estimating the creatine pool size in vivo with 14 C and 15 N labelled isotopes. Skeletal muscle mass (kg) was then calculated by dividing the creatine pool size (g) by muscle creatine concentration (g/kg) measured on a single muscle biopsy or estimated from the literature. This approach for quantifying skeletal muscle mass is generating renewed interest with the recent introduction of a practical stable isotope (creatine-(methyl-d 3 )) dilution method for estimating the creatine pool size across the full human lifespan. The need for a muscle biopsy has been eliminated by assuming a constant value for whole-body skeletal muscle creatine concentration of 4.3 g/kg wet weight. The current single compartment model of estimating creatine pool size and skeletal muscle mass rests on four main assumptions: tracer absorption is complete; tracer is all retained; tracer is distributed solely in skeletal muscle; and skeletal muscle creatine concentration is known and constant. Three of these assumptions are false to varying degrees. Not all tracer is retained with urinary isotope losses ranging from 0% to 9%; an empirical equation requiring further validation is used to correct for spillage. Not all tracer is distributed in skeletal muscle with non-muscle creatine sources ranging from 2% to 10% with a definitive value lacking. Lastly, skeletal muscle creatine concentration is not constant and varies between muscles (e.g. 3.89-4.62 g/kg), with diets (e.g. vegetarian and omnivore), across age groups (e.g. middle-age, ~4.5 g/kg; old-age, 4.0 g/kg), activity levels (e.g. athletes, ~5 g/kg) and in disease states (e.g. muscular dystrophies, <3 g/kg). Some of the variability in skeletal muscle creatine concentrations can be attributed to heterogeneity in the proportions of wet skeletal muscle as myofibres, connective tissues, and fat. These observations raise serious concerns regarding the accuracy of the deuterated-creatine dilution method for estimating total body skeletal muscle mass as now defined by cadaver analyses of whole wet tissues and in vivo approaches such as magnetic resonance imaging. A new framework is needed in thinking about how this potentially valuable method for measuring the creatine pool size in vivo can be used in the future to study skeletal muscle biology in health and disease.

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Creatine, Potassium and Phosphorus Content of Cardiac and Voluntary Muscle.

Cited by 9 publications

References 0 publications

Metabolic MR imaging of regional triglyceride and creatine content in the human heart

Metabolic MR imaging of regional triglyceride and creatine content in the human heart

Total body skeletal muscle mass estimated by magnetic resonance imaging and creatine (methyl‐d₃) dilution in athletes

D₃‐creatine dilution for skeletal muscle mass measurement: historical development and current status

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Creatine, Potassium and Phosphorus Content of Cardiac and Voluntary Muscle.

Cited by 9 publications

References 0 publications

Metabolic MR imaging of regional triglyceride and creatine content in the human heart

Metabolic MR imaging of regional triglyceride and creatine content in the human heart

Total body skeletal muscle mass estimated by magnetic resonance imaging and creatine (methyl‐d3) dilution in athletes

D3‐creatine dilution for skeletal muscle mass measurement: historical development and current status

Contact Info

Product

Resources

About

Total body skeletal muscle mass estimated by magnetic resonance imaging and creatine (methyl‐d₃) dilution in athletes

D₃‐creatine dilution for skeletal muscle mass measurement: historical development and current status