scholarly journals Skeletal muscle arteriolar function following myocardial infarction: Analysis of branch-order effects

2011 ◽  
Vol 81 (3) ◽  
pp. 337-343 ◽  
Author(s):  
Michael A. Tevald ◽  
John D. Lowman ◽  
Roland N. Pittman
Author(s):  
Feng Li-Li ◽  
Li Bo-Wen ◽  
Xi Yue ◽  
Tian Zhen-Jun ◽  
Cai Meng-Xin

Objectives: Myocardial infarction (MI)-induced heart failure (HF) is commonly accompanied with profound effects on skeletal muscle. With the process of MI-induced HF, perturbations in skeletal muscle contribute to muscle atrophy. Exercise is viewed as a feasible strategy to prevent muscle atrophy. The aims of this study were to investigate whether exercise could alleviate MI-induced skeletal muscle atrophy via insulin-like growth factor 1 (IGF-1) pathway in mice. Materials and Methods: Male C57/BL6 mice were used to establish the MI model and divided into three groups: sedentary MI group, MI with aerobic exercise group and MI with resistance exercise group, sham-operated group was used as control. Exercise-trained animals were subjected to four-weeks of aerobic exercise (AE) or resistance exercise (RE). Cardiac function, muscle weight, myofiber size, levels of IGF-1 signaling and proteins related to myogenesis, protein synthesis and degradation and cell apoptosis in gastrocnemius muscle were detected. And H2O2-treated C2C12 cells were intervened with recombinant human IGF-1, IGF-1R inhibitor NVP-AEW541 and PI3K inhibitor LY294002 to explore the mechanism. Results:Exercises up-regulated the IGF-1/IGF-1R-phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling, increased the expressions of Pax7, myogenic regulatory factors (MRFs) and protein synthesis, reduced protein degradation and cell apoptosis in MI-mice. In vitro, IGF-1 up-regulated the levels of Pax7 and MRFs, mTOR and P70S6K, reduced MuRF1, MAFbx and inhibited cell apoptosis via IGF-1R-PI3K/Akt pathway. Conclusion: AE and RE, safely and effectively, alleviate skeletal muscle atrophy by regulating the levels of myogenesis, protein degradation and cells apoptosis in mice with MI via activating IGF-1/IGF-1R-PI3K/Akt pathway.


1997 ◽  
Vol 83 (4) ◽  
pp. 1291-1299 ◽  
Author(s):  
Michael D. Delp ◽  
Changping Duan ◽  
John P. Mattson ◽  
Timothy I. Musch

Delp, Michael D., Changping Duan, John P. Mattson, and Timothy I. Musch. Changes in skeletal muscle biochemistry and histology relative to fiber type in rats with heart failure. J. Appl. Physiol. 83(4): 1291–1299, 1997.—One of the primary consequences of left ventricular dysfunction (LVD) after myocardial infarction is a decrement in exercise capacity. Several factors have been hypothesized to account for this decrement, including alterations in skeletal muscle metabolism and aerobic capacity. The purpose of this study was to determine whether LVD-induced alterations in skeletal muscle enzyme activities, fiber composition, and fiber size are 1) generalized in muscles or specific to muscles composed primarily of a given fiber type and 2) related to the severity of the LVD. Female Wistar rats were divided into three groups: sham-operated controls ( n = 13) and rats with moderate ( n = 10) and severe ( n = 7) LVD. LVD was surgically induced by ligating the left main coronary artery and resulted in elevations ( P < 0.05) in left ventricular end-diastolic pressure (sham, 5 ± 1 mmHg; moderate LVD, 11 ± 1 mmHg; severe LVD, 25 ± 1 mmHg). Moderate LVD decreased the activities of phosphofructokinase (PFK) and citrate synthase in one muscle composed of type IIB fibers but did not modify fiber composition or size of any muscle studied. However, severe LVD diminished the activity of enzymes involved in terminal and β-oxidation in muscles composed primarily of type I fibers, type IIA fibers, and type IIB fibers. In addition, severe LVD induced a reduction in the activity of PFK in type IIB muscle, a 10% reduction in the percentage of type IID/X fibers, and a corresponding increase in the portion of type IIB fibers. Atrophy of type I fibers, type IIA fibers, and/or type IIB fibers occurred in soleus and plantaris muscles of rats with severe LVD. These data indicate that rats with severe LVD after myocardial infarction exhibit 1) decrements in mitochondrial enzyme activities independent of muscle fiber composition, 2) a reduction in PFK activity in type IIB muscle, 3) transformation of type IID/X to type IIB fibers, and 4) atrophy of type I, IIA, and IIB fibers.


1982 ◽  
Vol 28 (1) ◽  
pp. 166-169 ◽  
Author(s):  
P M Bayer ◽  
M Boehm ◽  
P Hajdusich ◽  
H Hotschek ◽  
H Koehn ◽  
...  

Abstract We examined sera from six different groups of patients for CK-MB activity by means of two commercially available tests, an immunoinhibition method (E. Merck) and the CK-MB test as used with the aca (Du Pont). In the first group of patients (suspicion of myocardial infarction) the correlation between the two methods was good: r = 0.9191, y = 1.068x -- 0.888, x = 18.7 U/L, y = 19.0 U/L. In the second group, patients with high adenylate kinase activity, no interference was detectable on the aca, whereas the immunoinhibition method yielded falsely high CK-MB values. The third group consisted of persons with macro-CK-BB in their serum. In the immunoinhibition test these patients usually showed a high CK-MB:total CK ratio, whereas such results were rarely found for the aca. The fourth group, patients with a different electrophoretic mobility of their CK-isoenzymes (migration of an active band towards the cathode), were detected by the immunoinhibition method (high ratio of CK-MB to total CK), but not with the aca. In the presence of free CK-BB (group five) the immunoinhibition test resulted in "falsely" high CK-MB values, whereas CK-BB was retained on the column of the aca. In skeletal muscle diseases (group six) results by the two methods differed, values for CK-MB on the aca being much higher. It was demonstrated experimentally that this was due to CK-MM with altered surface charge.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
M J Gomes ◽  
A R R Lima ◽  
L U Pagan ◽  
F C Damatto ◽  
L R S Oliveira ◽  
...  

Abstract Background Skeletal muscle changes contribute to reduced physical performance after myocardial infarction (MI). Exercise has been recommended to stable patients. However, the effects of resistance exercise after MI are not clear. We compared the effects of aerobic and resistance exercise initiated during compensated cardiac remodeling in infarcted rat gastrocnemius muscle. Methods Three months after MI induction, Wistar rats were divided into four groups: Sham (n=20); sedentary MI (MI-S, n=9); aerobic exercised MI (MI-A, n=9); and resistance exercised MI (MI-R, n=13). Exercised rats trained three times a week for 12 weeks on a treadmill or ladder. Energy metabolism, oxidative stress markers, and antioxidant enzyme activities were assessed by spectrophotometry. Satellite cells activation markers (MyoD, NCAM, and myosin heavy chain neonatal isoform) were assessed by immunofluorescence or Western blot (Pax-7). Statistical analysis: ANOVA or Mann Whitney. Results Physical aerobic capacity was greater in MI-A and strength gain higher in MI-R. Cardiac structures and left ventricular function evaluated by echocardiogram did not differ between infarcted groups. Histological analysis showed that MI size and gastrocnemius cross sectional area did not differ between infarcted groups. Oxygen reactive species production was higher in MI-S than Sham and lipid hydroperoxide concentration was lower in MI-A than the other groups. Catalase activity was higher and glutathione peroxidase lower in infarcted groups than Sham. Superoxide dismutase activity was higher in Sham and MI-R than MI-S. Skeletal muscle metabolism enzyme activity did not differ between groups, except for increase pyruvate kinase in MI-S against the other groups, and β-hydroxyacyl CoA dehydrogenase in MI-S against Sham. Satellite cell activation and protein expression of MAPK and NF-kB did not differ between groups. Conclusion Aerobic and resistance exercise respectively improves physical capacity and muscle strength without changing echocardiographic parameters of infarcted rats. Myocardial infarction increases oxygen reactive species production and changes antioxidant enzyme activity and glucose and fatty acid metabolism. Aerobic exercise is superior to resistance exercise against oxidative stress reducing muscle lipid hydroperoxide concentration and attenuating change in glutathione peroxidase activity. Acknowledgement/Funding Financial support: Fapesp, CNPq, Capes, and UNESP


1999 ◽  
Vol 31 (Supplement) ◽  
pp. S365
Author(s):  
P. C. Pfeifer ◽  
K. L. Luther ◽  
S. Wolfram ◽  
N. Cardona ◽  
K. S. Hageman ◽  
...  

1994 ◽  
Vol 87 (4) ◽  
pp. 403-406 ◽  
Author(s):  
C. H. Thompson ◽  
G. J. Kemp ◽  
B. Rajagopalan ◽  
G. K. Radda

1. The effect of experimental myocardial infarction on exercise and recovery of rat skeletal muscle was studied using 31P n.m.r. 4 weeks post-operatively. 2. Myocardial infarction (12 ± 3% of left ventricular volume), insufficient to produce haemodynamic manifestations of heart failure, was without significant effect on exercise bioenergetics of skeletal muscle. 3. Citrate synthase activity was reduced by 17% in the infarcted animals and there was a marked slowing of the rate of phosphocreatine recovery after infarction (half-time 0.7 ± 0.1 min to 1.6 ± 0.2 min) in the absence of evidence of left ventricular failure or hypertrophy. 4. The study of recovery bioenergetics could provide a more sensitive measure of mitochondrial function than exercise, where no bioenergetic abnormality was detected. 5. Myocardial infarction can produce evidence of mitochondrial abnormality in skeletal muscle in the absence of haemodynamic compromise.


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