Muscle and strength loss will occur during periods of physical inactivity and immobilization. Creatine supplementation may have a favorable effect on muscle mass and strength independently of exercise. The purpose of this study was to determine the effects of creatine supplementation on upper limb muscle mass and muscle performance after immobilization. Before the study, creatine-naïve men (n = 7; 18-25 years) were assessed for lean tissue mass (dual-energy X-ray absorptiometry), strength (1-repetition maximum [1RM] isometric single arm elbow flexion/extension), and muscle endurance (maximum number of single-arm isokinetic elbow flexion/extension repetitions at 60% 1RM). After baseline measures, subjects had their dominant or nondominant (random assignment) upper limb immobilized (long arm plaster cast) at 90 degrees elbow flexion. Using a single-blind crossover design, subjects received placebo (maltodextrin; 4 x 5 gxd-1) during days 1-7 and creatine (4 x 5 gxd-1) during days 15-21. The cast was removed during days 8-14 and 22-29. The dependent measures of lean tissue mass, strength, and endurance were assessed at baseline, postcast, and after the study. During immobilization, compared with isocaloric placebo, creatine supplementation better maintained lean tissue mass (Cr +0.9% vs. PLA -3.7%, p < 0.05), elbow flexor strength (Cr -4.1% vs. PLA -21.5%, p < 0.05), and endurance (Cr -9.6% vs. PLA -43%, p < 0.05), and elbow extensor strength (Cr -3.8% vs. PLA -18%, p < 0.05) and endurance (Cr -6.5% vs. PLA -35%, p < 0.05). These results indicate that short-term creatine supplementation attenuates the loss in muscle mass and strength during upper-arm immobilization in young men.
"Creatine monohydrate supplementation has been shown to reduce the catabolic response of hind limb immobilization in rats . Additionally, Johnston et al.  have demonstrated that short-term creatine monohydrate supplementation (7 days) attenuates losses of muscle mass and strength during upper-arm immobilization in young men. Furthermore, prolonged creatine monohydrate supplementation has been reported to increase satellite cell proliferation and differentiation in resistance-trained subjects versus a placebo group . "
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to examine if L-leucine (Leu), β-hydroxy-β-methylbutyrate (HMB), or creatine monohydrate (Crea) prevented potential atrophic effects of myostatin (MSTN) on differentiated C2C12 myotubes.
After four days of differentiation, myotubes were treated with MSTN (10 ng/ml) for two additional days and four treatment groups were studied: 1) 3x per day 10 mM Leu, 2) 3x per day 10 mM HMB, 3) 3x per day 10 mM Crea, 4) DM only. Myotubes treated with DM without MSTN were analyzed as the control condition (DM/CTL). Following treatment, cells were analyzed for total protein, DNA content, RNA content, muscle protein synthesis (MPS, SUnSET method), and fiber diameter. Separate batch treatments were analyzed for mRNA expression patterns of myostatin-related genes (Akirin-1/Mighty, Notch-1, Ski, MyoD) as well as atrogenes (MuRF-1, and MAFbx/Atrogin-1).
MSTN decreased fiber diameter approximately 30% compared to DM/CTL myotubes (p < 0.001). Leu, HMB and Crea prevented MSTN-induced atrophy. MSTN did not decrease MPS levels compared to DM/CTL myotubes, but MSTN treatment decreased the mRNA expression of Akirin-1/Mighty by 27% (p < 0.001) and MyoD by 26% (p < 0.01) compared to DM/CTL myotubes. shRNA experiments confirmed that Mighty mRNA knockdown reduced myotube size, linking MSTN treatment to atrophy independent of MPS. Remarkably, MSTN + Leu and MSTN + HMB myotubes had similar Akirin-1/Mighty and MyoD mRNA levels compared to DM/CTL myotubes. Furthermore, MSTN + Crea myotubes exhibited a 36% (p < 0.05) and 86% (p < 0.001) increase in Akirin-1/Mighty mRNA compared to DM/CTL and MSTN-only treated myotubes, respectively.
Leu, HMB and Crea may reduce MSTN-induced muscle fiber atrophy by influencing Akirin-1/Mighty mRNA expression patterns. Future studies are needed to examine if Leu, HMB and Crea independently or synergistically affect Akirin-1/Mighty expression, and how Akirin-1/Mighty expression mechanistically relates to skeletal muscle hypertrophy in vivo.
Journal of the International Society of Sports Nutrition 08/2014; 11(1):38. DOI:10.1186/1550-2783-11-38 · 1.91 Impact Factor
"The longer artificial ventilation is implemented, the more difficulties such patients experience in resuming independent breathing. Since Cr has been shown to significantly alleviate muscle disuse atrophy (Johnston et al. 2009), it is to be expected that resumption of breathing and rehabilitation of ICU patients may also be positively influenced by Cr. The same, of course, holds true for severely ill patients presenting with cachexia, as often occurs for cancer patients. "
[Show abstract][Hide abstract] ABSTRACT: The pleiotropic effects of creatine (Cr) are based mostly on the functions of the enzyme creatine kinase (CK) and its high-energy product phosphocreatine (PCr). Multidisciplinary studies have established molecular, cellular, organ and somatic functions of the CK/PCr system, in particular for cells and tissues with high and intermittent energy fluctuations. These studies include tissue-specific expression and subcellular localization of CK isoforms, high-resolution molecular structures and structure-function relationships, transgenic CK abrogation and reverse genetic approaches. Three energy-related physiological principles emerge, namely that the CK/PCr systems functions as (a) an immediately available temporal energy buffer, (b) a spatial energy buffer or intracellular energy transport system (the CK/PCr energy shuttle or circuit) and (c) a metabolic regulator. The CK/PCr energy shuttle connects sites of ATP production (glycolysis and mitochondrial oxidative phosphorylation) with subcellular sites of ATP utilization (ATPases). Thus, diffusion limitations of ADP and ATP are overcome by PCr/Cr shuttling, as most clearly seen in polar cells such as spermatozoa, retina photoreceptor cells and sensory hair bundles of the inner ear. The CK/PCr system relies on the close exchange of substrates and products between CK isoforms and ATP-generating or -consuming processes. Mitochondrial CK in the mitochondrial outer compartment, for example, is tightly coupled to ATP export via adenine nucleotide transporter or carrier (ANT) and thus ATP-synthesis and respiratory chain activity, releasing PCr into the cytosol. This coupling also reduces formation of reactive oxygen species (ROS) and inhibits mitochondrial permeability transition, an early event in apoptosis. Cr itself may also act as a direct and/or indirect anti-oxidant, while PCr can interact with and protect cellular membranes. Collectively, these factors may well explain the beneficial effects of Cr supplementation. The stimulating effects of Cr for muscle and bone growth and maintenance, and especially in neuroprotection, are now recognized and the first clinical studies are underway. Novel socio-economically relevant applications of Cr supplementation are emerging, e.g. for senior people, intensive care units and dialysis patients, who are notoriously Cr-depleted. Also, Cr will likely be beneficial for the healthy development of premature infants, who after separation from the placenta depend on external Cr. Cr supplementation of pregnant and lactating women, as well as of babies and infants are likely to be of benefit for child development. Last but not least, Cr harbours a global ecological potential as an additive for animal feed, replacing meat- and fish meal for animal (poultry and swine) and fish aqua farming. This may help to alleviate human starvation and at the same time prevent over-fishing of oceans.
"Studies have shown several benefits of creatine supplementation, such as increased muscle power  , increased fat-free mass    and increase strength in healthy subjects . The benefits of Cr supplementation on exercise performance have been extended as a possible therapeutic agent in the treatment of disease conditions . Creatine (Cr) (Fig. 1) is a non-essential dietary element occurring naturally in the human body and is partly synthesized by the kidney, pancreas and liver (approximately 1–2 g per day), and partly ingested with food (approximately 1–5 g per day), especially with meat and fish . "
[Show abstract][Hide abstract] ABSTRACT: In this study, Raman spectroscopy was employed in order to provide information about the effects of different doses of creatine on bone tissue composition of phosphate apatite (960 cm −1), carbonate apatite (1170 cm −1) representing the mineral content and collagen matrix (amide I, 1665 cm −1). The animals (27 Balb-C male) were divided into three groups (n = 9 per group): control (CON), supplemented with 0.5 g/kg (Cre-0.5) and with 2.0 g/kg (Cre-2.0) creatine. The experiment was carried out for thirty days. After this time, the right femur of each animal was harvested. The specimens were assessment by FT-Raman spectroscopy and in a total of 81 spectra were acquired in the medial diaphysis of the femur. The Raman data strongly suggest that only the creatine supplementation of 0.5 g/kg effective to the bone constitution. Furthermore, the present results demonstrate that creatine ingestion provokes decrease in the relative presence of carbonate in the chemical constitution of bones. The decrease in the carbonate content can be associated to a significantly bone resistance altered to several mammalians. The analysis evidenced that the mineral concentrations in the Raman spectroscopy could be a feasible method for non-invasive or minimally invasive assessment of bone tissue composition. Probably this high sensitivity can be employed to determine spectral profiles, such as wavelength of maximum absorption and maximum intensity of absorption of each wavelength, of several bone diseases.
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