Adipose tissue thickness affects in vivo quantitative near-IR spectroscopy in human skeletal muscle

2001 ◽  
Vol 101 (1) ◽  
pp. 21 ◽  
Author(s):  
M.C.P. VAN BEEKVELT ◽  
M.S. BORGHUIS ◽  
B.G.M. VAN ENGELEN ◽  
R.A. WEVERS ◽  
W.N.J.M. COLIER
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Ir Spectroscopy ◽  
Human Skeletal Muscle ◽  
Tissue Thickness ◽  
Near Ir

Adipose tissue thickness affects in vivo quantitative near-IR spectroscopy in human skeletal muscle

2001 ◽  
Vol 101 (1) ◽  
pp. 21-28 ◽  
Author(s):  
M. C. P. VAN BEEKVELT ◽  
M. S. BORGHUIS ◽  
B. G. M. VAN ENGELEN ◽  
R. A. WEVERS ◽  
W. N. J. M. COLIER
Keyword(s):  
Adipose Tissue ◽  
Ir Spectroscopy ◽  
Maximum Voluntary Contraction ◽  
Skinfold Thickness ◽  
Voluntary Contraction ◽  
Poor Correlation ◽  
Tissue Thickness ◽  
Isometric Handgrip ◽  
Near Ir

The influence of adipose tissue thickness (ATT) on near-IR spectroscopy (NIRS) measurements in vivo was studied in the human flexor digitorum superficialis muscle at rest and during sustained isometric handgrip exercise. NIRS was used for the quantitative measurement of muscle O2 consumption (mVo2) and forearm blood flow (FBF) in 78 healthy subjects. Skinfold thickness ranged from 1.4 to 8.9 mm within the group. Resting mVo2 was 0.11±0.04 ml of O2 min-1 100 g-1, and FBF was 1.28±0.82 ml min-1 100 ml-1. There was a negative correlation (r =-0.70, P ≤ 0.01), indicating a decrease in mVo2 with increasing ATT. mVo2 in the 10 leanest subjects appeared to be twice as high as that in the 10 subjects with the highest ATT. A poor correlation (r = 0.29, P ≤ 0.01) was found between ATT and FBF. The gender difference that we found for mVo2 was due to the difference in ATT between female and male subjects. No correlation was found between maximum voluntary contraction and mVo2, nor between maximum voluntary contraction and ATT, indicating that the contraction force did not confound our results. These results show that ATT has a substantial confounding influence on in vivo NIRS measurements, and that it is essential to incorporate this factor into future NIRS muscle studies in order to justify comparisons between different groups. To facilitate such comparisons, upper and lower boundaries for normal values of mVo2 and FBF in relation to ATT are presented.

Adipose tissue thickness and optical properties affect differential pathlength factor in NIRS studies on human skeletal muscle

2021 ◽  
Author(s):  
Ileana Pirovano ◽  
Simone Porcelli ◽  
Rebecca Re ◽  
Lorenzo Spinelli ◽  
Davide Contini ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Optical Properties ◽  
Adipose Tissue ◽  
Human Skeletal Muscle ◽  
Tissue Thickness

scholarly journals Noninvasive evaluation of skeletal muscle mitochondrial capacity with near-infrared spectroscopy: correcting for blood volume changes

2012 ◽  
Vol 113 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Terence E. Ryan ◽  
Melissa L. Erickson ◽  
Jared T. Brizendine ◽  
Hui-Ju Young ◽  
Kevin K. McCully
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Oxygen Consumption ◽  
Infrared Spectroscopy ◽  
Blood Volume ◽  
Near Infrared ◽  
Tissue Thickness ◽  
Volume Changes ◽  
Mitochondrial Capacity

Near-infrared spectroscopy (NIRS) is a well-known method used to measure muscle oxygenation and hemodynamics in vivo. The application of arterial occlusions allows for the assessment of muscle oxygen consumption (mV̇o2) using NIRS. The aim of this study was to measure skeletal muscle mitochondrial capacity using blood volume-corrected NIRS signals that represent oxygenated hemoglobin/myoglobin (O2Hb) and deoxygenated hemoglobin/myoglobin (HHb). We also assessed the reliability and reproducibility of NIRS measurements of resting oxygen consumption and mitochondrial capacity. Twenty-four subjects, including four with chronic spinal cord injury, were tested using either the vastus lateralis or gastrocnemius muscles. Ten healthy, able-bodied subjects were tested on two occasions within a period of 7 days to assess the reliability and reproducibility. NIRS signals were corrected for blood volume changes using three different methods. Resting oxygen consumption had a mean coefficient of variation (CV) of 2.4% (range 1–32%). The recovery of oxygen consumption (mV̇o2) after electrical stimulation at 4 Hz was fit to an exponential curve, which represents mitochondrial capacity. The time constant for the recovery of mV̇o2was reproducible with a mean CV of 10% (range 1–22%) only when correcting for blood volume changes. We also examined the effects of adipose tissue thickness on measurements of mV̇o2. We found the mV̇o2measurements using absolute units to be influenced by adipose tissue thickness (ATT), and this relationship was removed when an ischemic calibration was performed, supporting its use to compare mV̇o2between individuals of varying ATT. In conclusion, in vivo oxidative capacity can be assessed using blood volume-corrected NIRS signals with a high degree of reliability and reproducibility.

Physical exercise increases autophagic signaling through ULK1 in human skeletal muscle

2015 ◽  
Vol 118 (8) ◽  
pp. 971-979 ◽  
Author(s):  
Andreas Buch Møller ◽  
Mikkel Holm Vendelbo ◽  
Britt Christensen ◽  
Berthil Forrest Clasen ◽  
Ann Mosegaard Bak ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Physical Exercise ◽  
Light Chain ◽  
Human Skeletal Muscle ◽  
Transgenic Animal ◽  
Dependent Manner ◽  
Healthy Humans ◽  
Transgenic Animal Models ◽  
Exercise Induced

Data from transgenic animal models suggest that exercise-induced autophagy is critical for adaptation to physical training, and that Unc-51 like kinase-1 (ULK1) serves as an important regulator of autophagy. Phosphorylation of ULK1 at Ser555 stimulates autophagy, whereas phosphorylation at Ser757 is inhibitory. To determine whether exercise regulates ULK1 phosphorylation in humans in vivo in a nutrient-dependent manner, we examined skeletal muscle biopsies from healthy humans after 1-h cycling exercise at 50% maximal O2 uptake on two occasions: 1) during a 36-h fast, and 2) during continuous glucose infusion at 0.2 kg/h. Physical exercise increased ULK1 phosphorylation at Ser555 and decreased lipidation of light chain 3B. ULK1 phosphorylation at Ser555 correlated positively with AMP-activated protein kinase-α Thr172 phosphorylation and negatively with light chain 3B lipidation. ULK1 phosphorylation at Ser757 was not affected by exercise. Fasting increased ULK1 and p62 protein expression, but did not affect exercise-induced ULK1 phosphorylation. These data demonstrate that autophagy signaling is activated in human skeletal muscle after 60 min of exercise, independently of nutritional status, and suggest that initiation of autophagy constitutes an important physiological response to exercise in humans.

scholarly journals FGF-2–dependent signaling activated in aged human skeletal muscle promotes intramuscular adipogenesis

2021 ◽  
Vol 118 (37) ◽  
pp. e2021013118 ◽  
Author(s):  
Sebastian Mathes ◽  
Alexandra Fahrner ◽  
Umesh Ghoshdastider ◽  
Hannes A. Rüdiger ◽  
Michael Leunig ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Transcriptional Activation ◽  
Human Skeletal Muscle ◽  
Muscle Growth ◽  
Muscle Cells ◽  
Adeno Associated Virus ◽  
Adult Skeletal Muscle

Aged skeletal muscle is markedly affected by fatty muscle infiltration, and strategies to reduce the occurrence of intramuscular adipocytes are urgently needed. Here, we show that fibroblast growth factor-2 (FGF-2) not only stimulates muscle growth but also promotes intramuscular adipogenesis. Using multiple screening assays upstream and downstream of microRNA (miR)-29a signaling, we located the secreted protein and adipogenic inhibitor SPARC to an FGF-2 signaling pathway that is conserved between skeletal muscle cells from mice and humans and that is activated in skeletal muscle of aged mice and humans. FGF-2 induces the miR-29a/SPARC axis through transcriptional activation of FRA-1, which binds and activates an evolutionary conserved AP-1 site element proximal in the miR-29a promoter. Genetic deletions in muscle cells and adeno-associated virus–mediated overexpression of FGF-2 or SPARC in mouse skeletal muscle revealed that this axis regulates differentiation of fibro/adipogenic progenitors in vitro and intramuscular adipose tissue (IMAT) formation in vivo. Skeletal muscle from human donors aged >75 y versus <55 y showed activation of FGF-2–dependent signaling and increased IMAT. Thus, our data highlights a disparate role of FGF-2 in adult skeletal muscle and reveals a pathway to combat fat accumulation in aged human skeletal muscle.

scholarly journals Microdialysis of skeletal muscle at rest

1999 ◽  
Vol 58 (4) ◽  
pp. 919-923 ◽  
Author(s):  
Jan Henriksson
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Human Skeletal Muscle ◽  
Human Metabolism ◽  
High Expectations ◽  
Perfusate Flow ◽  
Muscle Research ◽  
Interstitial Glucose

Techniques in human skeletal muscle research are by necessity predominantly 'descriptive'.Microdialysis has raised high expectations that it could meet the demand for a method that allows 'mechanistic' investigations to be performed in human skeletal muscle. In the present review, some views are given on how well the initial expectations on the use of the microdialysis technique in skeletal muscle have been fulfilled, and the areas in which additional work is needed in order to validate microdialysis as an important metabolic technique in this tissue. The microdialysis catheter has been equated to an artificial blood vessel, which is introduced into the tissue. By means of this 'vessel' the concentrations of compounds in the interstitial space can be monitored. The concentration of substances in the collected samples is dependent on the rate of perfusate flow. When perfusate flow is slow enough to allow complete equilibration between interstitial and perfusate fluids, the concentration in the perfusate is maximal and identical to the interstitial concentration. Microdialysis data may be influenced by changes in blood flow, especially in instances where the tissue diffusivity limits the recovery in vivo, i.e. when recovery in vitro is 100 %, whereas the recovery in vivo is less than 100 %. Microdialysis data indicate that a significant arterial-interstitial glucose concentration gradient exists in skeletal muscle but not in adipose tissue at rest. While the concentrations of glucose and lactate in the dialysate from skeletal muscle are close to the expected values, the glycerol values obtained for muscle are still puzzling. Ethanol added to the perfusate will be cleared by the tissue at a rate that is determined by the nutritive blood flow (the microdialysis ethanol technique). It is concluded that microdialysis of skeletal muscle has become an important technique for mechanistic studies in human metabolism and nutrition.

Effects of a 3-day fast on regional lipid and glucose metabolism in human skeletal muscle and adipose tissue

2007 ◽  
Vol 191 (3) ◽  
pp. 205-216 ◽  
Author(s):  
J. Gjedsted ◽  
L. C. Gormsen ◽  
S. Nielsen ◽  
O. Schmitz ◽  
C. B. Djurhuus ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Glucose Metabolism ◽  
Human Skeletal Muscle
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