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Oxygen Transport
Published in James N. Cobley, Gareth W. Davison, Oxidative Eustress in Exercise Physiology, 2022
P.N. Chatzinikolaou, N.V. Margaritelis, A.N. Chatzinikolaou, V. Paschalis, A.A. Theodorou, I.S. Vrabas, A. Kyparos, M.G. Nikolaidis
Once inside the muscle cell, oxygen flow to mitochondria is achieved by two ways: (i) as dissolved oxygen and (ii) via myoglobin-mediated delivery (Pias, 2020). Intracellular oxygen bound to myoglobin exceeds free oxygen by a ratio of 30:1, leaving an approximate sarcoplasmic free oxygen of ≈3.2 μM at 37°C (Pias, 2020). The role of myoglobin has been debated over the years, with the prevailing theories being that it serves as a (1) short-term oxygen storage (e.g., at rest), (2) oxygen transporter to mitochondria (e.g., during exercise) and (3) redox catalyst (Meyer, 2004). Oxygen binding to myoglobin during exercise could decrease the intramyocellular oxygen pressure gradient and enhance oxygen diffusion (Clanton, Hogan and Gladden, 2013). On the other, exercise-induced muscle damage increases serum myoglobin concentration (Balnave and Thompson, 1993) limiting oxygen availability intracellularly. Another molecule with the ability to store oxygen inside muscle is cytoglobin, which is found in micromolar concentrations (Fago et al., 2004). Despite the limited information in exercise conditions, cytoglobin has been reported to buffer intracellular oxygen (Clanton, Hogan and Gladden, 2013), regulate NO• availability (Mathai et al., 2020) and serve a role in muscle repair in mice (Singh et al., 2014).
Effects of Hypoxia/Blood Flow Restriction on Cellular Adaptations to Training
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Scott J. Dankel, Jeremy P. Loenneke
Other physiologic adaptations that are regulated by increased activity of HIF-1α include an up-regulation of the signalling protein, vascular endothelial growth factor (VEGF), which is responsible for the formation of new blood vessels (i.e., angiogenesis). Increased capillarization would theoretically improve one's ability to transport oxygen and nutrients, while also clearing metabolic by-products. While there is some suggestion that new blood vessels are formed as a result of hypoxic exposure (1), others have suggested that there is not an increase in blood vessels per se, but rather an increase in blood vessels per unit of muscle mass (12, 16), and this is related to a decrease in muscle mass accompanying hypoxia acclimation. With that being said, an increase in the ratio of capillaries to muscle fibre area would still enable a greater transport of oxygen and clearance of waste products. Additionally, an increase in myoglobin content may enhance the ability to carry and store oxygen within the muscle and generate adenosine triphosphate (ATP), the body's energy source.
Medical Problems in Alcoholics
Published in Frank Lynn Iber, Alcohol and Drug Abuse as Encountered in Office Practice, 2020
Severe drinkers often have muscular pains, elevation of the aldolase or CPK in the serum, and muscular atrophy. Occasionally this is associated with myoglobin in the serum and urine and may produce renal excretory problems. These problems are confined to very severe drinkers. With cessation of drinking the muscle returns to normal. Although this abnormality is frequent, it is not particularly important.22
Determination of histopathological effects and myoglobin, periostin gene-protein expression levels in Danio rerio muscle tissue after acaricide yoksorrun-5EC (hexythiazox) application
Published in Drug and Chemical Toxicology, 2023
Yücel Başımoğlu Koca, Serdar Koca, Zübeyde Öztel, Erdal Balcan
We found that following yoksorrun (hexythiazox) treatments, myoglobin level was increased, depending on the skeletal muscle atrophy. This can point at two things: firstly, the acaricide may have reduced the oxygen content of the water. Secondly, oxygen may be insufficient in the muscle tissue due to muscle damage. Therefore, the unknown myoglobin gene expression mechanisms may be induced in intact and/or slightly damaged muscle cells to obtain the required oxygen. On the other hand, previous reports suggested that this pesticide is highly toxic to larvae of Tetranychus urticae but not harmful for deutonymph and adults (Dekeyser 2005, Leviticus et al.2020). More recently, Demaeght et al. (2014) proposed that hexythiazox binds to central pore region of chitin synthase enzyme and block the chitin translocation (Demaeght et al.2014). In a recent study, the regulatory effect of glycogen synthase and glycogen phosphorylase on chitin biosynthesis was investigated (Zhang et al.2019). Glycogen synthase is a key glycosyltransferase in the glycogen biosynthesis. Muscle glycogen is an essential energy source during mechanical action. To evaluate the glycogen content in hexythiazox-treated zebrafish skeletal muscle, we performed PAS technique. Our results indicated that glycogen is decreased upon the pesticide treatment. These data suggest that hexythiazox is not only responsible for the loss of muscle mass in zebrafish but also responsible for the decreasing of glycogen deposits in the skeletal muscles.
Serum creatine kinase levels are not associated with an increased need for continuous renal replacement therapy in patients with acute kidney injury following rhabdomyolysis
Published in Renal Failure, 2022
Liuniu Xiao, Xiao Ran, Yanxia Zhong, Yue Le, Shusheng Li
The myoglobin released from damaged muscles plays a dominant role in the pathogenesis ofRM–induced AKI [10]. Myoglobin is an iron-containing small protein with a molecular weight of 17.8 kDa and exists at a low concentration in serum under physiological conditions [11]. However, for a skeletal muscle injury, serum myoglobin levels increase within one hour and return to a normal range within one to six hours after lesion resolution. Myoglobin is freely filtered by the glomerulus and absorbed in the proximal tubule by endocytosis [12]. Excess myoglobin released into the circulation will lead to myoglobinuria and renal insufficiency, which brings about renal tubular obstruction and oxidative injury. A persistently increased serum creatinine, as well as a decreased glomerular filtration rate (eGFR), predicts deterioration of renal functions, resulting in AKI.
Cardioprotective effects of corilagin on doxorubicin induced cardiotoxicity via P13K/Akt and NF-κB signaling pathways in a rat model
Published in Toxicology Mechanisms and Methods, 2022
Jing Huang, Ying Lei, Shengping Lei, Xinwen Gong
Cardiac biomarkers are largely circulating molecules or proteins which can be found in blood. The levels of MYO, H-FABP, GP-BBP, TGF-β, cTnI and BNP were elevated in DOX induced rats, whereas corilagin treatment reduced these cardiac markers. No particular changes were observed in corilagin alone treated rats and control. These biomarkers are used for the primary analysis of myocardial infarction. Myoglobin is mainly found in the cytoplasm of cardiac myocytes. Serum analysis of myoglobin is necessary for the quick determination of heart attack and thrombolytic treatment (Klocke et al. 1982). In the vein of myoglobin, measurement of H-FABP is the primary detection for cardiac dysfunction which gets rapidly released into the blood during myocardial injury (De Groot et al. 2001). Glycogen phosphorylase isoenzyme BB (GP-BB) is the glucose provider for heart muscle cells and it is released upon cardiac injury (Lippi et al. 2013).