Myoglobin content in human skeletal muscle and myocardium: relation to fibre size and oxidative capacity

Abstract

Myoglobin, muscle fibre diameter, and citrate synthase activity were measured in leg muscle of untrained and trained men and in the myocardium from the apex of the left ventricle and from papillary muscle in patients subjected to open heart surgery. The citrate synthase (CS) activity was 60% higher in trained than in untrained skeletal muscle. In the myocardium it was around four times greater than in untrained skeletal muscle but there was no difference between the apex of the left ventricle and papillary muscle. The fibre diameter varied almost threefold between the different groups of muscles with the largest diameter in untrained skeletal muscle and the with the largest diameter in untrained skeletal muscle and the smallest in papillary muscle. The myoglobin content in trained skeletal muscle did not differ from that of untrained muscle. In the left ventricle it was only 40% of that found in untrained muscle while papillary muscle had almost twice as high a myoglobin content as did the left ventricle. The ratio between myoglobin and fibre diameter, however, was of similar magnitude in skeletal muscle and the left ventricle while it was twice as high in papillary muscle as in the other muscles. In conclusion, the diffusion distance in terms of fibre diameter decreased with increased oxidative capacity (CS activity), when comparing the statistical means of the four different groups. The capacity for oxygen diffusion in relation to oxygen demand measured as the ratio of myoglobin to fibre diameter appeared to be of similar magnitude in skeletal muscle and left ventricle but was higher in papillary muscle.

Mild mitochondrial uncoupling impacts cellular aging in human muscles in vivo

“…Table 1 (15). Similarly, the values for myoglobin (Mb) intermuscular concentration, [Mb], fell within a range of concentrations (0.26-0.52 mM) in tissue biopsies taken from adult quadriceps muscles (16)(17)(18). Most of the age-related differences were either not significant or small (Ͻ15%).…”

“…Resting muscle metabolism is measured to avoid the confounding effects of energetic differences between fiber types during exercise to permit focusing on mitochondrial energetics and the impact of uncoupling on cellular aging. [Mb], fell within a range of concentrations (0.26-0.52 mM) in tissue biopsies taken from adult quadriceps muscles (16)(17)(18). Most of the age-related differences were either not significant or small (Ͻ15%).…”

Utility of Serum Ratio of Heart-Type Fatty Acid-Binding Protein to Myoglobin for Cardiac Damage Regardless of Renal Dysfunction

“…The H-FABP content in cardiac muscle is higher than that in skeletal muscle, whereas the myoglobin content in cardiac muscle is lower than that in skeletal muscle. 7,11 Therefore, there is a sharp contrast in the content of each protein in the heart and skeletal muscle. The molecular weight of H-FABP is 15 kDa and that of myoglobin is 18 kDa, therefore it is expected that the sieving effect of hemodialysis dialysers on H-FABP and myoglobin would be similar because these proteins have almost the same molecular weights.…”

Office Cardiologists Cooperative Study on Whole Blood Rapid Panel Tests in Patients With Suspicious Acute Myocardial Infarction

“…12,13 Comparative studies for the diagnosing of AMI have demonstrated that quantitative measurement of H-FABP is more sensitive than both myoglobin and CK-MB measurements, and more specific than myoglobin. 14,15 Clinical investigations of the release kinetics of H-FABP and other biochemical markers have revealed that H-FABP is elevated above the cut-off level within 3 h of onset, reaching a peak value at 4 h, and its release into the blood is approximately 24-36 h after onset of AMI.…”