Postmaximal contraction blood volume responses are blunted in obese and type 2 diabetic subjects in a muscle-specific manner

Sánchez, Otto A.; Copenhaver, Elizabeth A.; Chance, Marti A.; Fowler, Michael J.; Towse, Theodore F.; Kent‐Braun, Jane A.; Damon, Bruce M.

doi:10.1152/ajpheart.00060.2011

Cited by 21 publications

(21 citation statements)

References 69 publications

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“…The current study extends these findings to adults over 60 and includes the posterior leg (SOL) as well as the AC. It is well documented that microvascular function can be influenced by BMI (32) and hypertension (11). To account for these factors in our study, we examined age-related BOLD differences in a BMI-matched subgroup without hypertension and the age effect remained significant.…”

Section: Discussionmentioning

confidence: 99%

“…those that cannot be resolved in MRI images (22, 24, 40). Reduced BOLD magnitude or prolonged BOLD time courses have been reported in obesity (32), peripheral arterial disease (10), and diabetics with microvascular complications (37). Muscle BOLD responses are also remarkably higher in young, endurance trained adults compared to sedentary adults (40, 41) highlighting the influence of physical activity on peripheral vascular function.…”

Section: Introductionmentioning

confidence: 99%

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Age Reduces Microvascular Function in the Leg Independent of Physical Activity

Tonson

Noble

Meyer

et al. 2017

Medicine &Amp; Science in Sports &Amp; Exercise

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The microvasculature is critical in the control of blood flow. Aging and reduced physical activity may both decrease microvascular function. Purpose The primary aim was to evaluate the influence of age on microvascular function in adults with similar physical activity levels (PA). Secondary aims were to assess the reliability of muscle functional MRI in older adults and the relationship between physical activity and microvascular function in older adults. Methods Microvascular BOLD responses were measured in young adults (YA, n=12, 21±1 (±SD) years old, PA=239±73×103 counts/day) and older adults (OA, n=12, 64±4 years old, PA=203±48×103 counts/day). Functional MR images (3T, echo planar blood-oxygen-level dependent (BOLD)), of the leg were acquired following brief (1s) maximal voluntary isometric contractions. Test-retest reliability of BOLD responses and the Pearson correlation between peak BOLD and PA was assessed in a group of older adults (OA-r) with a broad range of PA (66±5 years old, n=9, PA range = 54×103 count/day to 674×103 counts/day). Results Peak BOLD microvascular responses were reduced for OA compared to YA. OA peak BOLD was 27% lower in the soleus (OA: 3.3±0.8% vs. YA: 4.5±1.4% YA, p=0.017) and 40% lower in the anterior compartment (1.6±0.6% OA vs. 2.7±1.1% YA, p=0.006). Coefficient of variation was 8.6% and 11.8% for peak BOLD in the soleus and anterior compartment, respectively, with an intraclass correlation of 0.950 for both muscle regions. The correlation between peak BOLD and PA was r ≥ 0.715, p ≤ 0.030. Conclusions Aging was associated with reduced microvascular function in leg muscles, independent of physical activity. The findings also revealed good reliability for BOLD MRI in older adults for the soleus and anterior compartment muscles.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Age Reduces Microvascular Function in the Leg Independent of Physical Activity

Tonson

Noble

Meyer

et al. 2017

Medicine &Amp; Science in Sports &Amp; Exercise

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“…Figure 4. Using a different assessment, Sanchez et al demonstrated impaired skeletal muscle blood flow in T2D and obese-matched controls (56% lower MRI signal intensity with maximum voluntary isometric contraction) [71]. There is evidence for both structural and functional abnormalities contributing to decrease skeletal muscle blood flow in diabetes.…”

Section: Muscle Contribution To Exercise Dysfunction In T2dmentioning

confidence: 99%

Type 2 diabetes mellitus and exercise impairment

Reusch

Bridenstine

Regensteiner

2013

Rev Endocr Metab Disord

117

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Limitations in physical fitness, a consistent finding in individuals with both type I and type 2 diabetes mellitus, correlate strongly with cardiovascular and all-cause mortality. These limitations may significantly contribute to the persistent excess cardiovascular mortality affecting this group. Exercise impairments in VO2 peak and VO2 kinetics manifest early on in diabetes, even with good glycemic control and in the absence of clinically apparent complications. Subclinical cardiac dysfunction is often present but does not fully explain the observed defect in exercise capacity in persons with diabetes. In part, the cardiac limitations are secondary to decreased perfusion with exercise challenge. This is a reversible defect. Similarly, in the skeletal muscle, impairments in nutritive blood flow correlate with slowed (or inefficient) exercise kinetics and decreased exercise capacity. Several correlations highlight the likelihood of endothelial-specific impairments as mediators of exercise dysfunction in diabetes, including insulin resistance, endothelial dysfunction, decreased myocardial perfusion, slowed tissue hemoglobin oxygen saturation, and impairment in mitochondrial function. Both exercise training and therapies targeted at improving insulin sensitivity and endothelial function improve physical fitness in subjects with type 2 diabetes. Optimization of exercise functions in people with diabetes has implications for diabetes prevention and reductions in mortality risk. Understanding the molecular details of endothelial dysfunction in diabetes may provide specific therapeutic targets for the remediation of this defect. Rat models to test this hypothesis are under study.

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“…Structural and functional changes in the microvasculature play a pivotal role in the pathogenesis of cardiovascular disease, hypertension, and diabetes (4,5). Therefore, muscle BOLD may be a powerful tool for measuring peripheral vascular function in individuals with peripheral arterial occlusive disease (6), obesity (7), and diabetes (7,8). Despite these advances, muscle BOLD imaging still suffers from relatively low signal-to-noise ratio (SNR) and an incomplete understanding of its biophysical basis.…”

Section: Introductionmentioning

confidence: 99%

“…Unlike the case in the brain, blood vessels in skeletal muscle are primarily oriented parallel to each other and to the muscle fibers (5), imparting an orientation-dependence to the extravascular BOLD effect. When muscle fibers are aligned parallel to B 0 , as is the case in many MRI experiments, the extravascular contribution to the BOLD effect at field strengths of 3T or lower is negligible (1,7,10). Conversely, at higher field strengths such as 7T, the T 2 * of blood (~9 ms; (11)) is several rimwa shorter than at 3T (12).…”

Section: Introductionmentioning

confidence: 99%

Post‐contractile BOLD contrast in skeletal muscle at 7 T reveals inter‐individual heterogeneity in the physiological responses to muscle contraction

et al. 2016

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Muscle blood oxygenation-level dependent (BOLD) contrast is greater in magnitude and potentially more influenced by extravascular BOLD mechanisms at 7 T than it is at lower field strengths. Muscle BOLD imaging of muscle contractions at 7 T could, therefore, provide greater or different contrast than at 3 T. The purpose of this study was to evaluate the feasibility of using BOLD imaging at 7 T to assess the physiological responses to in vivo muscle contractions. Thirteen subjects (four females) performed a series of isometric contractions of the calf muscles while being scanned in a Philips Achieva 7 T human imager. Following 2 s maximal isometric plantarflexion contractions, BOLD signal transients ranging from 0.3 to 7.0% of the pre-contraction signal intensity were observed in the soleus muscle. We observed considerable inter-subject variability in both the magnitude and time course of the muscle BOLD signal. A subset of subjects (n = 7) repeated the contraction protocol at two different repetition times (T : 1000 and 2500 ms) to determine the potential of T -related inflow effects on the magnitude of the post-contractile BOLD response. Consistent with previous reports, there was no difference in the magnitude of the responses for the two T values (3.8 ± 0.9 versus 4.0 ± 0.6% for T = 1000 and 2500 ms, respectively; mean ± standard error). These results demonstrate that studies of the muscle BOLD responses to contractions are feasible at 7 T. Compared with studies at lower field strengths, post-contractile 7 T muscle BOLD contrast may afford greater insight into microvascular function and dysfunction.

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Postmaximal contraction blood volume responses are blunted in obese and type 2 diabetic subjects in a muscle-specific manner

Cited by 21 publications

References 69 publications

Age Reduces Microvascular Function in the Leg Independent of Physical Activity

Age Reduces Microvascular Function in the Leg Independent of Physical Activity

Type 2 diabetes mellitus and exercise impairment

Post‐contractile BOLD contrast in skeletal muscle at 7 T reveals inter‐individual heterogeneity in the physiological responses to muscle contraction

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