Rapid vasodilation within contracted skeletal muscle in humans: new insight from concurrent use of diffuse correlation spectroscopy and Doppler ultrasound

Author(s):  
Masashi Ichinose ◽  
Mikie Nakabayashi ◽  
Yumie Ono

Previous studies showed that conduit artery blood flow rapidly increases after even a brief contraction of muscles within the dependent limb. Whether this rapid hyperemia occurs within contracted skeletal muscle in humans has yet to be confirmed, however. We therefore used diffuse correlation spectroscopy (DCS) to characterize the rapid hyperemia and vasodilatory responses within the muscle microvasculature induced by single muscle contractions in humans. Twenty-five healthy male volunteers performed single 1-s isometric handgrips at 20%, 40%, 60% and 80% of maximum voluntary contraction (MVC). DCS probes were placed on the flexor digitorum superficialis muscle, and a skeletal muscle blood flow index (SMBFI) was derived continuously. At the same time, brachial artery blood flow (BABF) responses were measured using Doppler ultrasound. Single muscle contractions evoked rapid, monophasic increases in both SMBFI and BABF that occurred within 3 s after release of contraction. The initial and peak responses increased with increases in contraction intensity and were greater for BABF than for SMBFI at all intensities. BABF reached its peak within 5 to 8 s after the end of contraction. The SMBFI continued to increase after the BABF passed its peak and was decreasing toward the resting level and peaked about 10 to 15 s after completion of the contraction. We conclude that single muscle contractions induce rapid, intensity-dependent hyperemia within the contracted skeletal muscle microvasculature. Moreover, the characteristics of the rapid hyperemia and vasodilatory responses of skeletal muscle microvessels differ from that simultaneously evaluated in the upstream conduit artery.

2020 ◽  
Vol 318 (1) ◽  
pp. R81-R88
Author(s):  
Wesley J. Tucker ◽  
Ryan Rosenberry ◽  
Darian Trojacek ◽  
Belinda Sanchez ◽  
Robert F. Bentley ◽  
...  

Near-infrared diffuse correlation spectroscopy (NIR-DCS) is an emerging technology for simultaneous measurement of skeletal muscle microvascular oxygen delivery and utilization during exercise. The extent to which NIR-DCS can track acute changes in oxygen delivery and utilization has not yet been fully established. To address this knowledge gap, 14 healthy men performed rhythmic handgrip exercise at 30% maximal voluntary contraction, with and without isolated brachial artery compression, designed to acutely reduce convective oxygen delivery to the exercising muscle. Radial artery blood flow (Duplex Ultrasound) and NIR-DCS derived variables [blood flow index (BFI), tissue oxygen saturation ([Formula: see text]), and metabolic rate of oxygen ([Formula: see text])] were simultaneously measured. During exercise, both radial artery blood flow (+51.6 ± 20.3 mL/min) and DCS-derived BFI (+155.0 ± 82.2%) increased significantly ( P < 0.001), whereas [Formula: see text] decreased −7.9 ± 6.2% ( P = 0.002) from rest. Brachial artery compression during exercise caused a significant reduction in both radial artery blood flow (−32.0 ± 19.5 mL/min, P = 0.001) and DCS-derived BFI (−57.3 ± 51.1%, P = 0.01) and a further reduction of [Formula: see text] (−5.6 ± 3.8%, P = 0.001) compared with exercise without compression. [Formula: see text] was not significantly reduced during arterial compression ( P = 0.83) due to compensatory reductions in [Formula: see text], driven by increases in deoxyhemoglobin/myoglobin (+7.1 ± 6.1 μM, P = 0.01; an index of oxygen extraction). Together, these proof-of-concept data help to further validate NIR-DCS as an effective tool to assess the determinants of skeletal muscle oxygen consumption at the level of the microvasculature during exercise.


2017 ◽  
Vol 9 (1) ◽  
pp. 131 ◽  
Author(s):  
Chandan-Ganesh Bangalore-Yogananda ◽  
Ryan Rosenberry ◽  
Sagar Soni ◽  
Hanli Liu ◽  
Michael D. Nelson ◽  
...  

Author(s):  
Yasuhiro Matsuda ◽  
Mikie Nakabayashi ◽  
Tatsuya Suzuki ◽  
Sinan Zhang ◽  
Masashi Ichinose ◽  
...  

Manipulative therapy (MT) is applied to motor organs through a therapist’s hands. Although MT has been utilized in various medical treatments based on its potential role for increasing the blood flow to the local muscle, a quantitative validation of local muscle blood flow in MT remains challenging due to the lack of appropriate bedside evaluation techniques. Therefore, we investigated changes in the local blood flow to the muscle undergoing MT by employing diffuse correlation spectroscopy, a portable and emerging optical measurement technology that non-invasively measures blood flow in deep tissues. This study investigated the changes in blood flow, heart rate, blood pressure, and autonomic nervous activity in the trapezius muscle through MT application in 30 volunteers without neck and shoulder injury. Five minutes of MT significantly increased the median local blood flow relative to that of the pre-MT period (p &lt; 0.05). The post-MT local blood flow increase was significantly higher in the MT condition than in the control condition, where participants remained still without receiving MT for the same time (p &lt; 0.05). However, MT did not affect the heart rate, blood pressure, or cardiac autonomic nervous activity. The post-MT increase in muscle blood flow was significantly higher in the participants with muscle stiffness in the neck and shoulder regions than in those without (p &lt; 0.05). These results suggest that MT could increase the local blood flow to the target skeletal muscle, with minimal effects on systemic circulatory function.


Author(s):  
Miles F. Bartlett ◽  
Scott M. Jordan ◽  
Dennis M. Hueber ◽  
Michael D. Nelson

Near-infrared diffuse correlation spectroscopy (DCS) is increasingly utilized to study relative changes in skeletal muscle blood flow. However, most diffuse correlation spectrometers assume that tissue optical properties- such as absorption (μa) and reduced scattering (μ's) coefficients- remain constant during physiological provocations, which is untrue for skeletal muscle. Here, we interrogate how changes in tissue μa and μ's affect DCS calculations of blood flow index (BFI). We recalculated BFI using raw autocorrelation curves and μa/μ's values recorded during a reactive hyperemia protocol in 16 healthy young individuals. First, we show that incorrectly assuming baseline μa and μ's substantially affects peak BFI and BFI slope when expressed in absolute terms (cm2/s, p<0.01) but these differences are abolished when expressed in relative terms (% baseline). Next, to evaluate the impact of physiologic changes in μa and μ's, we compared peak BFI and BFI slope when μa and μ's were held constant throughout the reactive hyperemia protocol versus integrated from a 3s-rolling average. Regardless of approach, group means for peak BFI and BFI slope did not differ. Group means for peak BFI and BFI slope were also similar following ad absurdum analyses, where we simulated supraphysiologic changes in μa/μ's. In both cases, however, we identified individual cases where peak BFI and BFI slope were indeed affected, with this result being driven by relative changes in μa over μ's. Overall, these results provide support for past reports in which μa/μ's were held constant but also advocate for real-time incorporation of μa and μ's moving forward.


2018 ◽  
Vol 315 (2) ◽  
pp. H242-H253 ◽  
Author(s):  
Masashi Ichinose ◽  
Mikie Nakabayashi ◽  
Yumie Ono

We used diffuse correlation spectroscopy to investigate sympathetic vasoconstriction, local vasodilation, and integration of these two responses in the skeletal muscle microvasculature of 20 healthy volunteers. Diffuse correlation spectroscopy probes were placed on the flexor carpi radialis muscle or vastus lateralis muscle, and a blood flow index was derived continuously. We measured hemodynamic responses during sympathoexcitation induced by forehead cooling, after which the effects of the increased sympathetic tone on vasodilatory responses during postocclusive reactive hyperemia (PORH) were examined. PORH was induced by releasing arterial occlusion (3 min) in an arm or leg. To increase sympathetic tone during PORH, forehead cooling was begun 60 s before the occlusion release and ended 60 s after the release. During forehead cooling, mean arterial pressure rose significantly and was sustained at an elevated level. Significant vasoconstriction and decreases in blood flow index followed by gradual blunting of the vasoconstriction also occurred. The time course of these responses is in good agreement with previous observations in animals. The acute sympathoexcitation diminished the peak vasodilation during PORH only in the vastus lateralis muscle, but it hastened the decline in vasodilation after the peak in both the flexor carpi radialis muscle and vastus lateralis muscle. Consequently, the total vasodilatory response assessed as the area of the vascular conductance during the first minute of PORH was significantly diminished in both regions. We conclude that, in humans, the integrated effects of sympathetic vasoconstriction and local vasodilation have an important role in vascular regulation and control of perfusion in the skeletal muscle microcirculation. NEW & NOTEWORTHY We used diffuse correlation spectroscopy to demonstrate that acute sympathoexcitation constrains local vasodilation in the human skeletal muscle microvasculature during postocclusive reactive hyperemia. This finding indicates that integration of sympathetic vasoconstriction and local vasodilation is importantly involved in vascular regulation and the control of perfusion of the skeletal muscle microcirculation in humans.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saeed Samaei ◽  
Piotr Sawosz ◽  
Michał Kacprzak ◽  
Żanna Pastuszak ◽  
Dawid Borycki ◽  
...  

AbstractMonitoring of human tissue hemodynamics is invaluable in clinics as the proper blood flow regulates cellular-level metabolism. Time-domain diffuse correlation spectroscopy (TD-DCS) enables noninvasive blood flow measurements by analyzing temporal intensity fluctuations of the scattered light. With time-of-flight (TOF) resolution, TD-DCS should decompose the blood flow at different sample depths. For example, in the human head, it allows us to distinguish blood flows in the scalp, skull, or cortex. However, the tissues are typically polydisperse. So photons with a similar TOF can be scattered from structures that move at different speeds. Here, we introduce a novel approach that takes this problem into account and allows us to quantify the TOF-resolved blood flow of human tissue accurately. We apply this approach to monitor the blood flow index in the human forearm in vivo during the cuff occlusion challenge. We detect depth-dependent reactive hyperemia. Finally, we applied a controllable pressure to the human forehead in vivo to demonstrate that our approach can separate superficial from the deep blood flow. Our results can be beneficial for neuroimaging sensing applications that require short interoptode separation.


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