Hypoxia- or hyperoxia-induced changes in arteriolar vasomotion in skeletal muscle microcirculation

Bertuglia, Silvia; Colantuoni, Antonio; Coppini, Giuseppe; Intaglietta, Marcos

doi:10.1152/ajpheart.1991.260.2.h362

Cited by 84 publications

(89 citation statements)

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“…13͑d͒ and 13͑e͔͒ suggested that arteriole A1 had a more significant vasomotion than did V1 under hyperoxia but with a similar oscillation frequency of ϳ1.6 cycles/ min ͑cpm͒, which is in good agreement with the observation from a previous invasive study. 112 By isolating the vasodilation effect, an increase of 96Ϯ 3% in the arteriolar diameter and 26Ϯ 5% in the venular diameter under hypoxia was observed ͓Fig. 13͑c͔͒, which agrees with a scanning laser fluorescent ophthalmoscopy study.…”

Section: Microhemodynamic Monitoringsupporting

confidence: 87%

Photoacoustic imaging and characterization of the microvasculature

2010

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Abstract. Photoacoustic ͑optoacoustic͒ tomography, combining optical absorption contrast and highly scalable spatial resolution ͑from micrometer optical resolution to millimeter acoustic resolution͒, has broken through the fundamental penetration limit of optical ballistic imaging modalities-including confocal microscopy, two-photon microscopy, and optical coherence tomography-and has achieved high spatial resolution at depths down to the diffusive regime. Optical absorption contrast is highly desirable for microvascular imaging and characterization because of the presence of endogenous strongly light-absorbing hemoglobin. We focus on the current state of microvascular imaging and characterization based on photoacoustics. We first review the three major embodiments of photoacoustic tomography: microscopy, computed tomography, and endoscopy. We then discuss the methods used to characterize important functional parameters, such as total hemoglobin concentration, hemoglobin oxygen saturation, and blood flow. Next, we highlight a few representative applications in microvascular-related physiological and pathophysiological research, including hemodynamic monitoring, chronic imaging, tumor-vascular interaction, and neurovascular coupling. Finally, several potential technical advances toward clinical applications are suggested, and a few technical challenges in contrast enhancement and fluence compensation are summarized.

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Section: Microhemodynamic Monitoringsupporting

confidence: 87%

Photoacoustic imaging and characterization of the microvasculature

2010

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“…It is possible that the vasomotion may reflect local autoregulatory responses to DEA/NO-induced hypotension, lowered TBF and hypoxia. Induction of vasomotor activity in normal arterioles has previously been reported in response to reduction in systemic pressure as well as reduction in oxygenation (Bertuglia et al, 1991;Vollmar et al, 1994). However, the effect seems to be controlled at the tissue level, rather than by systemic factors.…”

Section: Discussionmentioning

confidence: 90%

Effects of diethylamine/nitric oxide on blood perfusion and oxygenation in the R3230Ac mammary carcinoma

Shan

Rosner²,

Braun³

et al. 1997

Br J Cancer

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Summary The effects of intravenous diethylamine/nitric oxide (DEANNO), a short-acting nitric oxide (NO) donor, on systemic haemodynamics, muscle and tumour blood flow (MBF and TBF) and tumour oxygenation were examined in rats bearing subcutaneous R3230Ac carcinoma in the leg. The effects of DEA/NO on the diameters of tumour-feeding and normal arterioles were evaluated in window chambers with and without implanted tumours. DEA/NO reduced mean arterial pressure (MAP) when given at doses .100 nmol kg-1, with maximal suppression at 0.5-1 min followed by return to baseline within 20 min. DEA/NO did not affect MBF except at the highest doses (500 and 1000 nmol kg-'). In contrast, DEANNO reduced TBF and constricted tumour arterioles at doses .100 nmol kg-'. Tumour arteriolar vasomotion occurred in more than half the animals during hypotension and with a significantly higher frequency than in normal granulating tissue at a dose of 500 nmol kg-'. Normal arterioles rapidly and significantly vasodilated for about 3 min and then returned to baseline. The reductions in TBF and MAP were accompanied by synchronous reduction in tumour P02-Our findings suggest that DEA/NO decreases TBF in two ways. In the window chamber model, vascular steal occurs as normal arterioles adjacent to tumour dilate more than tumour arterioles during the initial period of hypotension. In leg tumours, the predominant mechanism is attributable to reduced perfusion pressure induced by lowered MAP, which decreases flow to the tumour, probably because of relatively higher flow resistance. The vasoconstriction and vasomotion in tumour arterioles during DEANNO-induced hypotension may reflect differences in regulatory metabolism of NO between neoplastic and normal arterioles. Thus, intravenous injection of a short-acting NO donor, DEANNO, decreases MAP and heart rate, leading to subsequent decreases in tumour blood flow and oxygenation.Keywords: DEANNO; nitric oxide; tumour blood flow; arteriolar diameter; vasomotion; tumour oxygenationThe relatively recent discovery that nitric oxide (NO) is a primary mediator of vascular tone has raised interest in its effects on tumour blood flow and oxygenation. It has previously been demonstrated that systemic or local administration of inhibitors of nitric oxide synthase (NOS) leads to reduction of tumour blood flow or bioenergetics that in some cases is relatively irreversible compared with its effects in normal tissue (Andrade et al, 1992;Wood et al, 1993 Wood et al, , 1994Meyer et al, 1995).Nitric oxide, either NO gas or released from NO donors, has also shown a radiosensitization effect in vitro (Howard-Flanders, 1957;Mitchell et al, 1993) and in tumours in vivo (Wood et al, 1993). An NO donor drug, diethylamine nitric oxide (DEA/NO), has been reported to sensitize hypoxic mammalian cells to irradiation; no sensitization was seen in aerobic cells (Mitchell et al, 1993). This NO-mediated hypoxic radiosensitization has been shown to be similar to that of oxygen (Howard-Flanders, 1957;Mitchell et al, 1993). Use of t...

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“…Under in vitro conditions, moderate hypoxia has been shown to inhibit L-type Ca 2ϩ channels in arterial smooth muscle cells leading to a decrease in intracellular Ca 2ϩ , promoting muscle relaxation without vasomotion (5). In contrast, in the hamster skeletal microcirculation, moderate to severe hypoxia has been shown to increase the frequency of arteriolar rhythmic diameter changes (2). Increased flow motion was suppressed by phentolamine, a selective ␣-adrenoceptor blocker (4).…”

Section: Discussionmentioning

confidence: 99%