Systemic and subcutaneous microvascular oxygen tension in conscious Syrian golden hamsters

Kerger, Heinz; Filho, Ivo P. Torres; Rivas, Maria Marta; Winslow, Robert M.; Intaglietta, Marcos

doi:10.1152/ajpheart.1995.268.2.h802

Cited by 68 publications

(79 citation statements)

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“…the kidney). The relative number of arteriolar vessels is high enough that some authors have suggested that a major source for oxygen transport in some tissues is the arterioles, rather than the capillaries (Ellsworth and Pittman, 1990;Kerger et al, 1995;Torres et al, 1996). Longitudinal gradients also exist in normal tissues, but, because of the redundancy of vascular supply, such gradients do not lead to vascular or tissue hypoxia in most cases (Duling and Berne, 1970;Ellsworth et al, 1987;Swain and Pittman, 1989).…”

Section: Discussionmentioning

confidence: 99%

Quantification of longitudinal tissue pO2 gradients in window chamber tumours: impact on tumour hypoxia

et al. 1999

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We previously reported that the arteriolar input in window chamber tumours is limited in number and is constrained to enter the tumour from one surface, and that the p O 2 of tumour arterioles is lower than in comparable arterioles of normal tissues. On average, the vascular p O 2 in vessels of the upper surface of these tumours is lower than the p O 2 of vessels on the fascial side, suggesting that there may be steep vascular longitudinal gradients (defined as the decline in vascular p O 2 along the afferent path of blood flow) that contribute to vascular hypoxia on the upper surface of the tumours. However, we have not previously measured tissue p O 2 on both surfaces of these chambers in the same tumour. In this report, we investigated the hypothesis that the anatomical constraint of arteriolar supply from one side of the tumour results in longitudinal gradients in p O 2 sufficient in magnitude to create vascular hypoxia in tumours grown in dorsal flap window chambers. Fischer-344 rats had dorsal flap window chambers implanted in the skin fold with simultaneous transplantation of the R3230AC tumour. Tumours were studied at 9–11 days after transplantation, at a diameter of 3–4 mm; the tissue thickness was 200 μm. For magnetic resonance microscopic imaging, gadolinium DTPA bovine serum albumin (BSA-DTPA-Gd) complex was injected i.v., followed by fixation in 10% formalin and removal from the animal. The sample was imaged at 9.4 T, yielding voxel sizes of 40 μm. Intravital microscopy was used to visualize the position and number of arterioles entering window chamber tumour preparations. Phosphorescence life time imaging (PLI) was used to measure vascular p O 2 . Blue and green light excitations of the upper and lower surfaces of window chambers were made (penetration depth of light ~50 vs >200 μm respectively). Arteriolar input into window chamber tumours was limited to 1 or 2 vessels, and appeared to be constrained to the fascial surface upon which the tumour grows. PLI of the tumour surface indicated greater hypoxia with blue compared with green light excitation ( P < 0.03 for 10th and 25th percentiles and for per cent pixels < 10 mmHg). In contrast, illumination of the fascial surface with blue light indicated less hypoxia compared with illumination of the tumour surface ( P < 0.05 for 10th and 25th percentiles and for per cent pixels < 10 mmHg). There was no significant difference in p O 2 distributions for blue and green light excitation from the fascial surface nor for green light excitation when viewed from either surface. The PLI data demonstrates that the upper surface of the tumour is more hy...

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Section: Discussionmentioning

confidence: 99%

Quantification of longitudinal tissue pO2 gradients in window chamber tumours: impact on tumour hypoxia

et al. 1999

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“…High-resolution microvascular PO2 measurements were made using phosphorescence quenching microscopy, which has been described in greater detail elsewhere (12). Oxygen measurements are based on the oxygen-dependent quenching of phosphorescence emitted by an albumin-bound metalloporphyrin complex after light excitation.…”

Section: Methodsmentioning

confidence: 99%

Microcirculatory changes during chronic adaptation to hypoxia

Saldı́var¹,

Cabrales²,

Tsai³

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

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Microcirculatory changes in the window chamber preparation in Syrian golden hamsters, secondary to chronic hypoxia adaptation, are presented herein. Adaptation was attained by keeping animals in a 10% oxygen environment for 1 wk and 5% the following week. The following groups were studied: group 1, adapted to chronic hypoxia and kept in a 5% oxygen environment throughout the experiment; group 2, adapted to chronic hypoxia and kept in a 21% oxygen environment 24 h before and during the experiment; and group 3, control. Adaptation caused venule enlargement and hematocrit increase (68.6 ± 2.44 in group 1, 70 ± 2.66 in group 2, and 43.27 ± 2.30 in group 3; P < 0.05). Whereas heart rate decreased in adapted animals, blood pressure remained constant. Group 1 presented alkalosis, hypocapnia, and hypoxemia. The adapted groups had decreased blood flow velocity in arterioles and veins. We found no difference in microvasculature oxygen tension between groups 2 and 3; however, the number of capillaries with flow was markedly reduced in group 1 but significantly increased in group 2. Our findings suggest that, as an adaptation to hypoxia, erythropoiesis may prove beneficial by increasing blood viscosity and shear stress, leading to vasodilatation, in addition to the increase in oxygen-carrying capacity. Calculations show that oxygen extraction in the tissue of the window chamber model was significantly lowered in adapted animals breathing 5% oxygen, but was unchanged from the control when breathing 21% oxygen, even though blood hemoglobin content was increased from 14.5 ± 0.07 g/dl at control to 21.04 ± 1.24 g/dl in the adapted animals ( P < 0.05).

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“…Data are given as means Ϯ SD for the indicated number of animals. Data were analyzed by using analysis of variance, followed by Fisher's protected leastsignificant difference test between the groups according to the previous studies (11,12,24). Student's t-test was used for the comparisons within each group.…”

Section: Methodsmentioning

confidence: 99%

Systemic and microvascular responses to hemorrhagic shock and resuscitation with Hb vesicles

Sakai

Takeoka

Wettstein

et al. 2002

American Journal of Physiology-Heart and Circulatory Physiology

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Systemic and subcutaneous microvascular oxygen tension in conscious Syrian golden hamsters

Cited by 68 publications

References 0 publications

Quantification of longitudinal tissue pO2 gradients in window chamber tumours: impact on tumour hypoxia

Quantification of longitudinal tissue pO2 gradients in window chamber tumours: impact on tumour hypoxia

Microcirculatory changes during chronic adaptation to hypoxia

Systemic and microvascular responses to hemorrhagic shock and resuscitation with Hb vesicles

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