Characterizing near-infrared spectroscopy responses to forearm post-occlusive reactive hyperemia in healthy subjects

Bopp, Christopher M.; Townsend, Dana K.; Barstow, Thomas J.

doi:10.1007/s00421-011-1898-z

Cited by 42 publications

(44 citation statements)

References 24 publications

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“…Within the skeletal muscle, light is absorbed by hemoglobin in small arterioles, capillaries, and venules of the microcirculation, causing changes in oxygenated, deoxygenated, and total hemoglobin NIRS signals, and provides information on the balance of oxygen delivery and utilization. 29,31,37 The NIRS signals arise predominantly from capillaries as these microvessels compose the largest portion of vascular volume in skeletal muscle (>90%), and the NIRS light can only pass through vessels <1 mm. 25,31,37,38 Thus, NIRS signals mainly reflect changes in capillary (hemoglobin related) oxygen levels and provide information on the microcirculation.…”

Section: Dipla Et Al Muscle Microvascular Dysfunction In Hypertensionmentioning

confidence: 99%

“…29,31,37 The NIRS signals arise predominantly from capillaries as these microvessels compose the largest portion of vascular volume in skeletal muscle (>90%), and the NIRS light can only pass through vessels <1 mm. 25,31,37,38 Thus, NIRS signals mainly reflect changes in capillary (hemoglobin related) oxygen levels and provide information on the microcirculation. 25,31,37,38 …”

Section: Dipla Et Al Muscle Microvascular Dysfunction In Hypertensionmentioning

confidence: 99%

“…The cuff was rapidly inflated to suprasystolic levels (ie, 250 mm Hg), to obstruct blood flow to forearm muscles and measure the maximal capacity for oxygen extraction by skeletal muscles. 31 Stable blood flow/volume was verified by total hemoglobin. The cuff was then rapidly deflated, and reoxygenation responses were recorded.…”

Section: Testing Procedures and Instrumentationmentioning

confidence: 99%

“…22,23 The peak hyperemic response was calculated as the difference between peak TSI during reperfusion and baseline TSI. 24,31 During exercise, peak and average TSI responses were used as indices of muscle oxygen extraction. 33 The BP response during the first minute of exercise (ΔBP=BP exercise −BP baseline ) was divided by the average TSI response during exercise and was used as an index of exercise BP rise per unit of muscle oxygenation (ie, ΔBP/ΔTSI).…”

Section: Testing Procedures and Instrumentationmentioning

confidence: 99%

“…25,31,37,38 Thus, NIRS signals mainly reflect changes in capillary (hemoglobin related) oxygen levels and provide information on the microcirculation. 25,31,37,38 …”

mentioning

confidence: 99%

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Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients

et al. 2017

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E ssential hypertension is characterized by sustained elevations of blood pressure (BP) that can lead to target organ damage and an increased risk for cardiovascular disease. 1Potential life-threatening outcomes of hypertension, such as stroke, renal insufficiency, and cardiac hypertrophy, had been initially perceived as a result of macrovascular alterations. These macrovascular events, however, do not occur independently of microvascular derangement. [2][3][4] Studies have shown that alterations in microvascular structure (rarefaction), vasomotor tonus (enhanced vasoconstriction or blunted vasodilation), and endothelial dysfunction are principal processes in the pathogenesis of hypertension and are evident in several organs/tissue types. [5][6][7][8] In the skeletal muscle, microvascularization is important for oxygen and nutrient supply and for effective metabolite clearance. Studies in hypertension have shown structural or functional impairments in the microvasculature within skeletal muscles, 8 implying a reduced capacity for oxygen delivery and exchange. Furthermore, animal studies using experimental models of hypertension suggested that mitochondrial dysfunction (ie, decreased expression of mitochondrial components and defects in respiratory complexes) and increased oxidative stress result in impaired oxidative capacity and reduced mitochondrial ATP production.9,10 Importantly, in these animals, the mitochondrial dysfunction and the reduced oxidative capacity were present before the development of hypertension, suggesting a possible role of these processes to the pathogenesis of hypertension.11 However, information on skeletal muscle microvascular alterations and oxidative Abstract-This study examined in vivo (1) skeletal muscle oxygenation and microvascular function, at rest and during handgrip exercise, and (2) their association with macrovascular function and exercise blood pressure (BP), in newly diagnosed, never-treated patients with hypertension and normotensive individuals. Ninety-one individuals (51 hypertensives and 40 normotensives) underwent office and 24-hour ambulatory BP, arterial stiffness, and central aortic BP assessment, followed by a 5-minute arterial occlusion and a 3-minute submaximal handgrip exercise. Changes in muscle oxygenated and deoxygenated hemoglobin and tissue oxygen saturation were continuously monitored by nearinfrared spectroscopy and beat-by-beat BP by Finapres. Hypertensives had higher (P<0.001) central aortic BP and pulse wave velocity versus normotensives and exhibited (1) a blunted tissue oxygen saturation response during occlusion, with slower (P=0.006) deoxygenation rate, suggesting reduced muscle oxidative capacity, and (2) a slower reoxygenation rate and blunted hyperemic response (P<0.05), showing reduced microvascular reactivity. Muscle oxygenation responses were correlated with aortic systolic and pulse pressure and augmentation index (P<0.05; age and body mass index (BMI) adjusted). When exercising at the same submaximal intensity, hypertensives required a sig...

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Section: Dipla Et Al Muscle Microvascular Dysfunction In Hypertensionmentioning

confidence: 99%

Section: Dipla Et Al Muscle Microvascular Dysfunction In Hypertensionmentioning

confidence: 99%

Section: Testing Procedures and Instrumentationmentioning

confidence: 99%

Section: Testing Procedures and Instrumentationmentioning

confidence: 99%

“…25,31,37,38 Thus, NIRS signals mainly reflect changes in capillary (hemoglobin related) oxygen levels and provide information on the microcirculation. 25,31,37,38 …”

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Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients

et al. 2017

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Idiopathic inflammatory myopathies evaluated by near-infrared spectroscopy

et al. 2015

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Impairments in microvascular function and skeletal muscle oxygenation in women with gestational diabetes mellitus: links to cardiovascular disease risk factors

et al. 2016

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Aims/hypothesis Gestational diabetes mellitus (GDM) is a risk factor for the development of endothelial dysfunction and cardiovascular disease. However, in vivo microvascular endothelial function in GDM has not been investigated. This study aimed to examine, using near-infrared spectroscopy (NIRS), whether: (1) there are differences in microvascular reactivity and skeletal muscle oxygen consumption (mVat rest and during exercise between GDM and uncomplicated pregnancies; and (2) ) and blunted hyperaemia (ΔTSI 6.8 ± 2.9 vs 9.5 ± 3.4) compared with controls (p < 0.01). Despite similar handgrip strength in the GDM and control groups (29.1 ± 8.1 vs 26.2 ± 10.4 kg, respectively), during repeated forearm contractions, women with GDM presented a blunted TSI response (6.5 ± 3.9 vs 19.2 ± 10.9; p < 0.01) and a reduced capacity to maintain the predetermined handgrip (23.4 ± 2.9 vs 27.4 ± 3.8%, p < 0.05). NIRS indices correlated with PWV, 24 h BP and blood glucose concentration earlier in pregnancy (r = 0.40-0.60; p < 0.05). Conclusions/interpretation Women with GDM exhibited a characteristic blunted TSI curve, showing alterations in muscle oxygenation and microvascular responsiveness compared with women with uncomplicated pregnancies. These alterations were manifested during exercise and possibly contribute to the reduced exercise tolerance in GDM. NIRS indices correlated with macrovascular indices (arterial stiffness) and 24 h BP.

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Characterizing near-infrared spectroscopy responses to forearm post-occlusive reactive hyperemia in healthy subjects

Cited by 42 publications

References 24 publications

Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients

Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients

Idiopathic inflammatory myopathies evaluated by near-infrared spectroscopy

Impairments in microvascular function and skeletal muscle oxygenation in women with gestational diabetes mellitus: links to cardiovascular disease risk factors

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