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Some other groups and circumstances
Published in Geoffrey P. Webb, Nutrition, 2019
In explosive events like short sprints, jumping or throwing, the energy supply of the muscle during the event is mainly from creatine phosphate plus a contribution from the anaerobic metabolism of glycogen. Creatine phosphate is the muscle’s short-term energy reserve and it can be used to convert ADP to ATP by transfer of a phosphate moiety:
Metabolic Diseases
Published in Stephan Strobel, Lewis Spitz, Stephen D. Marks, Great Ormond Street Handbook of Paediatrics, 2019
Stephanie Grünewald, Alex Broomfield, Callum Wilson
Creatine is required for the formation of creatine phosphate, an important short-term source for cellular energy. There are three known defects of creatine metabolism, arginine glycine amidinotransferase (AGAT), GAMT and creatine transporter defect. The latter is responsible for the transport of creatine across the blood–brain barrier. All three diseases result in decreased cerebral creatine. However, the additional peripheral symptoms seen in GAMT deficiency are thought to arise from the toxicity of accumulating guanidinoacetate. AGAT and GAMT deficiencies are inherited in an autosomal recessive manner, whereas defects in the creatine transporter are due to a defect in the X-linked gene SLC6A8. Several female carriers of SCL6A8 mutation have been recorded having a phenotype of mild learning problems.
Functional Foods
Published in Datta Sourya, Debasis Bagchi, Extreme and Rare Sports, 2019
Kamesh Venkatakrishnan, Chin-Kun Wang
During resting/full fed state (ATP are stored): free FAs (from plasma) undergo oxidation (β-oxidation) to yield acetyl co-A as well as NADH and FADH2, which enters TCA and ETC to produce ATP. These ATPs are used for storing excess glucose to glycogen by the process called glycogenesis. Moreover, these ATP were also used for converting creatine to creatine phosphate as a phosphate reserve to aid in ATP production (phosphagen system) during intense or strenuous exercise (Greenhaff, 1997). The remaining ATP is used for the regular (normal) contraction and relaxation process.
Effects of Creatine Supplementation on Properties of Muscle, Bone, and Brain Function in Older Adults: A Narrative Review
Published in Journal of Dietary Supplements, 2022
Scott C. Forbes, Darren G. Candow, Luis H. B. Ferreira, Tacito P. Souza-Junior
Accumulating research suggests that creatine supplementation acts through a variety of different cellular mechanisms (for reviews see (Candow et al. 2019a; Candow et al. 2019b; Chilibeck et al. 2017; Gualano et al. 2016; Kreider et al. 2017; Stares and Bains 2020). Creatine also aids in shuttling of high-energy phosphates from sites of ATP production (i.e. the mitochondria) to sites of ATP utilization via the creatine phosphate shuttle (Kreider et al. 2003; Wallimann et al. 1998). This mechanism is associated with a reduction in oxidative stress (Strumia et al. 2012). Animal studies have shown an attenuation of oxidative stress in plasma and muscles in rodents who ingested creatine. In addition, the antioxidant capacity of creatine supplemented rodents increased significantly (Deminice and Jordao 2012). Deminice et al. (2013) found an attenuation of inflammatory markers (TNF-α and C-reactive protein) following 1 week of creatine supplementation. These results are further supported by others that found creatine to have protective effects against tissue damage (Sestili et al. 2011). Creatine thus appears to protect mitochondrial DNA as well as preserve the integrity of mitochondria, and it may also protect ribonucleic acid (RNA) from oxidative damage (Sestili et al. 2011), however the precise mechanism(s) remains to be elucidated. Furthermore, PCr acts as a spatial energy buffer during periods of rapid ATP turnover (Greenhaff et al. 1993; Kreider et al. 2017), thereby buffering increases in hydrogen ions (H+) (Greenhaff et al. 1993).
Cystatin C as a biomarker of chronic kidney disease: latest developments
Published in Expert Review of Molecular Diagnostics, 2020
Stefanie W. Benoit, Eileen A. Ciccia, Prasad Devarajan
The most commonly used method of estimating glomerular filtration rate (GFR) is measurement of serum creatinine. Creatinine is a breakdown product of creatine phosphate in skeletal muscle and is derived from a patient’s native muscle metabolism as well as consumption of dietary creatine (e.g. meat and creatine supplements). While it is freely filtered by the renal glomeruli, with no reabsorption or renal metabolism, it is actively secreted by the proximal tubule. Due to the substantial amount of urinary creatinine derived from tubular secretion, GFR calculated by 24-creatinine clearance can exceed the measured GFR by the gold standard inulin clearance by 10% to 40% [4]. In addition, given the endogenous source of creatinine is skeletal muscle, there are a variety of demographic factors that affect serum creatinine, including age, gender, and race/ethnicity [5]. Multiple GFR estimating equations have been developed in an attempt to account for these variations. The equations recommended in 2012 by Kidney Disease Outcomes Quality Initiative are the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation for adults and the Updated ‘Bedside’ Schwartz equation for children [5]. However, only approximately 85% and 79% of estimated GFRs using these two equations, respectively, are within 30% of simultaneously accurately measured GFR values [5].
Effects of chronic treatment with gold nanoparticles on inflammatory responses and oxidative stress in Mdx mice
Published in Journal of Drug Targeting, 2020
Daniela Pacheco dos Santos Haupenthal, Jonathann Corrêa Possato, Rubya Pereira Zaccaron, Carolini Mendes, Matheus Scarpatto Rodrigues, Renata Tiscoski Nesi, Ricardo Aurino Pinho, Paulo Emilio Feuser, Ricardo Andrez Machado-de-Ávila, Clarissa M. Comim, Paulo Cesar Lock Silveira
Inflammation and elevation in concentrations of serum enzymes, such as creatine kinase (CK), are important features of DMD. CK catalyses the transfer of high-energy ATP phosphate to creatine, producing creatine phosphate, a component of muscle fibre cytosol. CK serum activity is positively correlated with the progressive muscle damage observed in DMD [31,32]. Fenichel et al. [33] reported an increase in the serum levels of CK, GOT, GPT and LDH, which are diagnostic markers of the disease. These results confirm the results of this study where increased CK and LDH levels were observed in muscle tissue of Mdx mice. Furthermore, such increases were reversed in tissue from mice treated with GNP [34–36]. Increased serum concentrations of ALT/GPT and AST/GOT are biomarkers of liver toxicity [37,38]. Treatment with 2.5, 7 and 21 mg/kg GNP did not increase the levels of these enzymes, suggesting that there was no pathological effect on the liver.