Biomechanical and Electrical Responses of Normal and Hypertensive Veins to Short-Term Pressure Increases

Monos, E.; Kauser, Katalin; Contney, Stephen J.; CowleyJr., Allen W.; Stekiel, William J.

doi:10.1007/978-3-662-00983-3_5

Cited by 9 publications

(12 citation statements)

References 6 publications

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“…As mentioned in the introduction, to our knowledge, only Monos and his co-workers (29,30,32,33,43) have been doing detailed studies on the biomechanical response of venous wall to blood pressure elevation. For example, Monos et al (30) studied the mechanical and morphological properties of the saphenous vein that was exposed to high blood pressure induced by tilting rats at a 45°angle (gravitational method) for 2 wk.…”

Section: Discussionmentioning

confidence: 99%

“…Later, Monos et al (32) studied the biomechanical response of the rat saphenous vein to the elevation of blood pressure induced by the above-mentioned method (animal tilting method, for 2 wk) and by surgically resecting 75% of renal mass (volume-expansion method, for 6 wk). In both cases, active, smooth muscle-related responses, which are expressed by the difference in vascular diameter between the total response observed in normal Krebs-Henseleit solution and the passive response obtained in calcium-free, magnesium-rich solution were significantly larger compared with the age-matched controls.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, Fridez et al. (8,9) have shown that normal vascular tone related to the smooth muscle cell, which is the sensing and effecting element of the adaptation process, was increased during the early phase of arterial adaptation to hypertension.As far as we know only Monos et al (30,32) directly studied the biomechanical effects of the chronic elevation of blood pressure in the vein, and much less is known about the remodeling of the venous wall compared with arteries. They chronically increased blood pressure in the vein of the lower extremity by exposing rats to head-up tilt for 2 wk, and they studied the pressure-diameter relations and wall thickness of the saphenous vein excised from the animals.…”

mentioning

confidence: 99%

“…As far as we know only Monos et al (30,32) directly studied the biomechanical effects of the chronic elevation of blood pressure in the vein, and much less is known about the remodeling of the venous wall compared with arteries. They chronically increased blood pressure in the vein of the lower extremity by exposing rats to head-up tilt for 2 wk, and they studied the pressure-diameter relations and wall thickness of the saphenous vein excised from the animals.…”

mentioning

confidence: 99%

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Biomechanical response of femoral vein to chronic elevation of blood pressure in rabbits

Hayashi

Mori

Miyazaki

2003

American Journal of Physiology-Heart and Circulatory Physiology

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response of femoral vein to chronic elevation of blood pressure in rabbits. Am J Physiol Heart Circ Physiol 284: H511-H518, 2003. First published September 26, 2002 10.1152/ajpheart.00620.2002-Venous diseases like iliofemoral deep vein thrombosis and valvular dysfunction induce venous hypertension. To know the effects of the hypertension on venous mechanics, blood pressure in the left femoral vein in the rabbit was chronically elevated by the constriction of the left external iliac vein. Wall dimensions and biomechanical properties of the femoral vein were studied in vitro at 1, 2, or 4 wk after surgery. Blood pressure measured immediately before the animal was killed was significantly higher in the left femoral vein than in the sham-operated, contralateral vein. Wall thickness was increased by blood pressure elevation even at 1 wk, which restored circumferential wall stress to a control level. The stress was kept at normal up to 4 wk. Vascular tone and vascular contractility were increased by the elevation of blood pressure; however, wall elasticity and compliance were kept at a normal level. These results are very similar to those observed in hypertensive arteries, indicating that not only arteries but veins optimally operate against blood pressure elevation.hypertrophy; remodeling; wall stress MANY EXPERIMENTAL STUDIES and clinical observations have shown that arteries change their dimensions and properties in response to the chronic elevation of blood pressure (10,14,16,17,19,41). One of the specific biomechanical phenomena appearing in response to arterial hypertension is wall thickening, which restores wall hoop stress to a normal, control level. In addition, vascular tone is increased, although arterial elasticity at in vivo working pressure changes to an optimal level. For example, Matsumoto and Hayashi (26,27) demonstrated in the rat with induced Goldblatt hypertension that the aortic hoop stress at in vivo systolic pressure, which should have been high soon after the induction of hypertension, was rapidly (within 2 wk) restored to a physiologically normal level because of wall hypertrophy and remained at the normal level thereafter. On one hand, the elastic modulus of the wall, which was also high soon after the induction of hypertension, became normal after a relatively long period of time, i.e., at 16 wk. In addition, Fridez et al. (8,9) have shown that normal vascular tone related to the smooth muscle cell, which is the sensing and effecting element of the adaptation process, was increased during the early phase of arterial adaptation to hypertension.As far as we know only Monos et al. (30,32) directly studied the biomechanical effects of the chronic elevation of blood pressure in the vein, and much less is known about the remodeling of the venous wall compared with arteries. They chronically increased blood pressure in the vein of the lower extremity by exposing rats to head-up tilt for 2 wk, and they studied the pressure-diameter relations and wall thickness of the saphenous vein excised from t...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Biomechanical response of femoral vein to chronic elevation of blood pressure in rabbits

Hayashi

Mori

Miyazaki

2003

American Journal of Physiology-Heart and Circulatory Physiology

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“…These mechanisms include an enhancement of the acute-pressure-induced myogenic response of saphenous vein with increases in smooth muscle cell count and in passive vessel diameter without much change in the wall thickness [1,[4][5][6]. Chronic head-up tilt also influences the microcirculatory network properties.…”

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Does Chronic Experimental Head-Down Tilt Alter Intramural Innervation Density of Limb Blood Vessels?

Lorant¹,

Raffai²,

Nádasy³

et al. 2005

JJP

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Earlier, substantial increases in the intramural sympathetic innervation density of rat hind-limb blood vessels were found after 2 weeks of experimental orthostasis with tubular 45° headup tilt cages. In the present study, we presumed that chronic head-down tilting induces opposite changes in the innervation density. Tilted rats were kept 45° head-down in long tubular cages for either 2 or 4 weeks (HDT2, HDT4), and the control animals were maintained in horizontal tilt cages for the same period (HOR2, HOR4). Segments of the saphenous and brachial veins and arteries were used for quantitative electron microscopic examinations. Intramural innervation density was defined by nerve terminal density (NTD) and synaptic microvesicle count (SVC) within the vascular Our previous work, applying a novel chronic 45°head-up tilt model of orthostasis [1,2], revealed several long-term vascular mechanisms supporting orthostatic tolerance in the hind limbs [3]. These mechanisms include an enhancement of the acute-pressure-induced myogenic response of saphenous vein with increases in smooth muscle cell count and in passive vessel diameter without much change in the wall thickness [1,[4][5][6]. Chronic head-up tilt also influences the microcirculatory network properties. A significant rarefaction of microvessels was found in the hind-limb oxidative skeletal muscles of rat after two weeks of orthostasis [7]. Branching angles decreased, and vessel diameters increased in the superficial venous system of the saphenous region of rats in response to long-term orthostasis [8]. The amount of electron-dense vesicles of ap- adventitia. Neither HDT2 nor HDT4 resulted in a decrease of NTD or SVC of the saphenous and brachial veins or arteries; instead, a tendency to increase was observed in some cases. Thus, in contrast to the large increases we found earlier in hind-limb vascular innervation density after 2 weeks of head-up tilting, head-down tilting of the same duration-or even twice as long-did not decrease the adventitial innervation density in our model. We assume that the quasi-free locomotor exercise the tilted animals in the long tubular cages were allowed may counteract a possible suppressive effect of chronic head-down tilt on hind-limb vascular innervation density. [The Japanese Journal of Physiology 55: [127][128][129][130][131][132][133][134] 2005] Key words: brachial vein, head-down tilt, saphenous artery, saphenous vein, vascular innervation.proximately 0.1-0.2 µm diameter (which we identified in the endothelium cells of rat saphenous vein) greatly decreased during two weeks of orthostatic body position [9,10].After 2 weeks of 45° head-tilting, among the most interesting observations we made in this model of orthostasis was a surprisingly large increase (nearly double) in the adventitial (intramural) sympathetic innervation density of hind-limb blood vessels, especially the veins [2]. This increase included both the density of nerve terminals (NTD) and the number of synaptic microvesicles in the terminals (SVC). The...

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Vacuole formation in the endothelium of rat extremity vessels depends on fixation techniques and vessel type

Raffai

Fehér

Nádasy

et al. 2004

Pathology - Research and Practice

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Biomechanical and Electrical Responses of Normal and Hypertensive Veins to Short-Term Pressure Increases

Cited by 9 publications

References 6 publications

Biomechanical response of femoral vein to chronic elevation of blood pressure in rabbits

Biomechanical response of femoral vein to chronic elevation of blood pressure in rabbits

Does Chronic Experimental Head-Down Tilt Alter Intramural Innervation Density of Limb Blood Vessels?

Vacuole formation in the endothelium of rat extremity vessels depends on fixation techniques and vessel type

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