記述言語：英語   掲載種別：研究論文（学術雑誌）  

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. 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 those simultaneously evaluated in the upstream conduit artery.NEW & NOTEWORTHY Through the concurrent use of diffuse correlation spectroscopy and Doppler ultrasound, we provide the first evidence in humans that a single brief muscle contraction evokes rapid, intensity-dependent hyperemia within the contracted skeletal muscle microvasculature and the upstream conduit artery. We also show that the magnitude and time course of the contraction-induced rapid hyperemia and vasodilatory responses within skeletal muscle microvessels significantly differ from those in the conduit artery.

DOI： 10.1152/ajpheart.00761.2020

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

We investigated the integration of sympathetic vasoconstriction and local vasodilation in the skeletal muscle and skin microvasculature of humans. In 39 healthy volunteers, we simultaneously measured the blood flow index in the flexor carpi radialis muscle using diffuse correlation spectroscopy and the skin using laser-Doppler flowmetry. We examined the effects of acute sympathoexcitation induced by forehead cooling on relatively weak and robust vasodilatory responses during postocclusive reactive hyperemia (PORH) induced by 70-sec and 10-min arterial occlusion in the upper arm. To increase sympathetic tone during PORH, forehead cooling was begun 60 sec before the occlusion release and ended 60 sec after the release. In the 70-sec occlusion trials, acute sympathoexcitation reduced the peak and duration of vasodilation in both skeletal muscle and skin. The inhibition of vasodilation by sympathoexcitation was blunted in both tissues by the robust vasodilatory stimulation produced by the 10-min occlusion, and the degree of blunting was greater in skeletal muscle than in skin, especially the initial and peak responses. Sympathoexcitation reduced the peak vasodilation only in skin, while it accelerated the initial vasodilation only in skeletal muscle. However, the decline in vasodilation after the peak was significantly hastened in skeletal muscle, shortening the duration of the vasodilation. We conclude that, in humans, the integration of sympathetic vasoconstriction and local vasodilation has different effects in skeletal muscle and skin and is likely an important contributor to the selective control of perfusion in the microcirculations of different tissues.

DOI： 10.14814/phy2.14070

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Renal hypoxia is an aggravating factor for tubulointerstitial damage, which is strongly associated with renal prognosis in diabetic kidney disease (DKD). Therefore, urinary markers that can detect renal hypoxia are useful for monitoring DKD. OBJECTIVE: To determine the correlation between urinary liver-type fatty acid-binding protein (L-FABP) and renal hypoxia using a novel animal model of type 2 diabetes. METHODS: Male spontaneously diabetic Torii (SDT) fatty rats (n = 6) were used as an animal model of type 2 diabetes. Age- and sex-matched Sprague-Dawley (SD) rats (n = 8) were used as controls. Body weight, systolic blood pressure, and blood glucose levels were measured at 8, 12, 16, and 24 weeks of age. Urine samples and serum and kidney tissues were collected at 24 weeks of age. Microvascular blood flow index (BFI) was measured using diffuse correlation spectroscopy before sampling both the serum and kidneys for the evaluation of renal microcirculation at the corticomedullary junction. RESULTS: Obesity, hyperglycemia, and hypertension were observed in the SDT fatty rats. Focal glomerular sclerosis, moderate interstitial inflammation, and fibrosis were significantly more frequent in SDT fatty rats than in SD rats. While the frequency of peritubular endothelial cells and phosphoendothelial nitric oxide synthase levels were similar in both types of rats, the degree of renal hypoxia-inducible factor-1α (HIF-1α) expression was significantly higher (and with no change in renal vascular endothelial growth factor expression levels) in the SDT fatty rats. Urinary L-FABP levels were significantly higher and renal microvascular BFI was significantly lower in the SDT fatty rats than in the SD rats. Urinary L-FABP levels exhibited a significant positive correlation with renal HIF-1α expression and a significant negative correlation with renal microvascular BFI. CONCLUSIONS: Urinary L-FABP levels reflect the degree of renal hypoxia in DKD in a type 2 diabetic animal model. Urinary L-FABP may thus prove useful as a renal hypoxia marker for monitoring DKD in patients with type 2 diabetes in clinical practice.

DOI： 10.1159/000503926

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

We propose a novel application of diffuse correlation spectroscopy to evaluate microvascular malfunctions of muscle tissue affected by hyperglycemia and determine their correlation with the severity of diabetic neuropathy at a later stage. Microvascular responses of the thigh muscle and the mechanical pain threshold of the hind paw of streptozotocin-induced type I diabetic rats were continuously monitored once per week for 70 days. Significantly decreased baseline blood flow and reactive hyperemia responses were observed as early as 1 week after hyperglycemia induction. The reactive hyperemia response at 2 weeks of hyperglycemia was highly correlated with the mechanical pain threshold at 8 weeks, at which time a decreased pain threshold was statistically confirmed in hyperglycemic rats relative to controls.

DOI： 10.1364/BOE.9.004539

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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.

DOI： 10.1152/ajpheart.00010.2018

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記述言語：英語   出版者・発行元：Japanese Society for Medical and Biological Engineering  

Diffuse correlation spectroscopy (DCS) is an emerging optical technique for noninvasive measurement of hemodynamics of living tissues. Using emitter and detector optical probes attached to the body surface, DCS estimates the mean speed of blood flow in the tissue, through which the emitted near-infrared light propagates (blood flow index: BFI). The advantage of DCS is that the mean blood flow in deeper tissues such as muscle layers can be measured noninvasively. To investigate the sensitivity of DCS in detecting the physiological changes of blood flow in deep and shallow tissues, we measured the blood flow speed in 14 healthy participants during a reactive hyperemia test and skin temperature changes. In the reactive hyperemia test, blood flow returned to the steady state faster in deep tissues than in shallow tissues, and temperature-dependent reallocation of local blood flow in shallow and deep tissues was clearly observed. These results demonstrate that DCS can measure the differences in physiological blood flow dynamics in deep and shallow tissues, suggesting the potential use of DCS to noninvasively quantify changes at microcirculation level in both shallow and deep tissue layers.

DOI： 10.14326/abe.6.53

DOI： 10.1117/12.2288044_references_DOI_QwVep9aHJlEga3zaZ46iU17wem8

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その他リンク： https://search.jamas.or.jp/link/ui/2018364077

記述言語：日本語   出版者・発行元：日本体育大学  

掲載誌：Yasuhiro Matsuda, Mikie Nakabayashi, Tatsuya Suzuki, Sinan Zhang, Masashi Ichinose, Yumie Ono (2022). Evaluation of Local Skeletal Muscle Blood Flow in Manipulative Therapy by Diffuse Correlation Spectroscopy, Frontiers in Bioengineering and Biotechnology, 9: 800051
研究紹介：国外学術誌掲載論文から

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出版者・発行元：IEEE  

DOI： 10.1109/ipc48725.2021.9592861

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-21K11457/

Using diffuse correlation spectroscopy we quantitatively verified that the manipulative therapy could significantly increase local muscle blood flow.

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出版者・発行元：Optica Publishing Group  

<jats:p>We developed a dual-channel diffuse correlation spectroscopy system, which was validated by simultaneous blood flow measurement of the skeletal muscles of the upper and lower limbs during the head-up-tilt test.</jats:p>

DOI： 10.1364/boda.2021.jtu4a.7

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-21K11457/

出版者・発行元：SPIE  

DOI： 10.1117/12.2545267

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17K19932/

出版者・発行元：SPIE  

DOI： 10.1117/12.2542876

DOI： 10.1109/ipc48725.2021.9592861_references_DOI_RtEHdCfn1uEGzC802OFfSNE0sud

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17K19932/

記述言語：日本語   出版者・発行元：日本体育大学  

手技療法は様々な医療の分野での治療の目的として運動器へ適用されている代表的な治療法である。手技療法は局所血流を増加させ，浮腫および疼痛を減少させるという仮定のもとに適用されているが，科学的な根拠に基づく計測方法や評価方法が確立されていない。本研究では，近年開発が進んでいる血流光計測技術である拡散相関分光法（diffuse correlation spectroscopy: DCS）を用いて，手技療法前後の局所筋血流の変化を非侵襲的かつ定量的に評価することを目的とした。健康な被験者（男性3名/女性3名，年齢：22.5±0.7歳）がこの研究に参加した。股関節を屈曲するために被験者は施術ベッドで背臥位とした。始めに疼痛が誘発されるまで股関節を最大屈曲させ，股関節屈曲角度と主観的疼痛感（visual analog scale: VAS）を計測した（Pre屈曲時）。続いて，腹臥位になり安静時5分間の大腿部後面の血流を計測した（Pre安静）。その後，5分間の手技療法を行い，手技療法後に再び大腿部後面の血流を計測した（Post安静）。最後に背臥位の状態でPre屈曲時と同角度まで股関節を屈曲した際のVAS値を再度計測した（Post屈曲時）。被験者は，2回の股関節屈曲の間に手技療法を行う手技療法条件と，手技療法を行わず腹臥位で安静とする対照条件の2試行をランダムな順序で行った。その結果，Post屈曲時のVAS値はPre屈曲時に比べて手技療法条件のみに減少傾向が確認された（p=0.08）が，対照条件では変化はみられなかった（p=0.41）。さらに，手技療法条件ではPre安静時に比べてPost安静時において筋血流速度の有意な増加がみられた（p<0.05）。このことは，手技療法による皮膚や筋組織への機械的な圧力が身体への静脈還流を促進し，組織血流の増加が引き起こされたことを示している。
本研究は科研費（助成金番号JP 17K19932）と立石科学振興財団（助成金番号 2177005）から支援を受けて行なった。
原著論文

CiNii Article

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J-GLOBAL

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その他リンク： http://id.ndl.go.jp/bib/029769472

出版者・発行元：SPIE  

DOI： 10.1117/12.2288044

DOI： 10.3389/fbioe.2021.800051_references_DOI_P3pwp2teSf4xwUd7dDM947V6Bug

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17K19932/

開催年月日： 2019年

記述言語：日本語  

拡散相関分光法(diffuse correlation spectroscopy: DCS)は、赤血球が近赤外光を拡散する性質に着目して、生体組織の血流速度を非侵襲的に計測する光学技術である。DCSは送光・受光プローブ間距離の変更によって深部組織の血流動態の情報を含むことができ、近赤外分光法との併用によって局所的な組織酸素消費動態(metabolic rate of oxygen extraction)を導出することができる。そのため、手術中や脳血管障害・睡眠時無呼吸症候群患者の脳血流動態のモニタリング・乳癌の位置検出・運動時筋血流の定量化など幅広い応用が期待されている。本発表では、DCSが組織血流の変化を高感度に検出可能であることを示す一例として、糖尿病モデルラットを用いた筋・腎組織の血流計測結果について紹介する。糖尿病モデルラットの下肢筋・腎皮質に対して定期的に反応性充血試験と血流計測を行い、DCSによる血流パラメータを取得したところ、感覚障害や筋力低下といった慢性症状の発言よりも早期に対照群に対する変化が生じ、糖尿病性合併症の早期診断におけるDCSの有用性を示すことができた。

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開催年月日： 2018年2月

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17K19932/