Arterial Wall Mechanics Research Articles

Ultrasonic measurement of arterial wall mechanics

Wollersheim, Hub C.; Buford, Gregory; Bundens, Warner; Fronek, Arnost Author Information

Abnormal arterial flow pattern in untreated essential hypertension: Possible link with the development of atherosclerosis

1. We compared the velocity waveforms in the superficial femoral artery measured by multichannel Doppler ultrasound in 45 subjects: 21 patients with untreated essential hypertension and 24 normal subjects of similar age and sex. 2. The pattern of arterial flow was abnormal in hypertensive patients, with the acceleration time, the duration of reverse flow and the time to maximum flow reversal being abbreviated. The internal arterial diameter, calculated from the velocity profile, was reduced despite raised pressure, suggesting altered arterial wall mechanics in essential hypertension. 3. These abnormalities will influence the wall shear stress, a major determinant of arterial function. The abnormal arterial wall mechanics and abnormal blood flow pattern may contribute to the increased risk of arterial disease in patients with untreated hypertension.

Effects of laser thermal angioplasty on arterial contractions and mechanics

In each of 8 rabbits, a fiberoptic with a 1.5 mm diameter metal tip was inserted into the abdominal aorta. After preheating with 8-10 watts of argon laser energy, the metal tip was passed through the external iliac artery. Thermal injury was evaluated by histology and by measuring arterial contractions and wall mechanics. The contralateral iliac artery was used as a control. Laser thermal angioplasty (LTA) produced foci of coagulation necrosis, medial thinning, and wall rupture. Concomitantly, maximal arterial contractile force was reduced by 80% (p less than 0.01) and arterial wall stiffness was decreased (p less than 0.05). These changes may have clinical implications with regard to the incidence and severity of vasospasm and restenosis following angioplasty.

Comparison of arterial wall properties in young and old racing greyhounds

Arteries were obtained from several sites in young (YGH) and old racing greyhounds (OGH). Segments were used for the determination of arterial wall mechanics under conditions of active (norepinephrine) and passive (Ca 2+ free and 2 mM EGTA) smooth muscle. Contiguous segments were used for the chemical analysis of connective tissue, water and electrolyte content. The passive stiffness of arteries from OGH was consistently greater than that of the YGH. Collagen content and the collagen-elastin ratio were larger at all sites in the OGH. However, the connective tissue changes were not considered to be of sufficient magnitude to explain the changes in passive mechanics. Maximum values of active stress development were generally lower in arteries from the OGH as was their relative cell content. Active stress development normalized to smooth muscle cell cross-section was not uniformly changed in arteries from OGH. In spite of the lower active stress development in some arteries, the ability of smooth muscle to constrict lumen diameter was not different between OGH and YGH at transmural pressures in the physiological range. While a number of changes occur in arteries of purebred greyhounds with aging, they appear to occur in such a fashion that normal function is not grossly altered.

Effects of chronic cigarette smoking on canine arteries.

Segments of carotid and femoral arteries were obtained from beagles subjected to cigarette smoking (12/day for 2 yr) and from unexposed controls. The segments were used for in vitro studies of active and passive mechanics, dose responses to norepinephrine (NE) and K+, connective tissue content, and water and electrolyte content and distribution. No significant differences in passive arterial wall mechanics or geometry at 100 mmHg were found, but a small (significant) increase in passive stiffness was found at wall loads corresponding to higher values of pressure for arteries from smokers. No significant changes in connective tissue composition were found at either site. No significant differences in maximum active force development were found at either site between the two groups. However, values of active force near the middle of the active force-length curve were lower (P less than 0.05) for smoker's arteries when expressed as a fraction of the maximum developed force. No differences in cell volume were found in arteries from the two groups. Mg2+ and K+ content of the femoral and Ca2+ content of both arteries were greater in the smokers. No difference in NE dose-response relations were found for either site. A statistically significant decrease in responsiveness to K+ was found for femoral arteries from smokers, but not for the carotids. The results of these studies demonstrate that some significant changes in arterial wall properties occur in beagle dogs exposed to chronic cigarette smoke.

Age-related changes in arterial wall mechanics and composition of NIA Fischer rats

Segments of carotid and tail arteries and descending thoracic aorta were obtained from the NIA colony of Fischer rats at ages 3, 12, 24 and 30 months. Measurements of pressure and diameter were made on intact cylindrical segments under conditions of active (147 mM K + and pssive (Ca 2+ -free and 2 mM EGTA) smooth muscle. These data were used to compute active and passive mechanics. Contiguous segments were used for the analysis of connective tissue, water and electrolyte contents. Passive stiffness of the carotid and tail arteries increased monotonically with increasing age. Collagen content in the aorta and tail artery generally increased with age, while elastin content decreased in the aorta and carotid artery. The ratio of collagen to elastin increased at all sites with age. Maximum values of active stress response (force development) increased from 3 to 12 months for the carotid artery, but decreased with age (at 24 and 30 months compared to 3 and 12 months) for the tail artery. Changes in relative cell content were such that active cellular force development was the same at all ages for the carotid artery but was smaller at 24 and 30 months compared to the younger animals for the tail artery. Decreased cellular force development by arterial smooth muscle is not an anatomically uniform finding in this animal model.

Experimental cerebral vasospasm arterial wall mechanics and connective tissue composition.

The elastic properties of the basilar artery were studied in control and treated dogs in which 3 ml of blood was injected intracisternally. Vascular specimens were resected transclivally as cylindrical segments and their external diameters were measured in vitro in the pressure range from 0 mm Hg to 250 mm Hg in the active condition of smooth muscle in Krebs-Ringer solution and in the passive condition in saline solution. The development of cerebral vasospasm was confirmed comparing the diameter difference between these two conditions. The experimental data indicated that vasospasm was most prominent on the 7th day after the treatment of blood injection. In the passive condition no significant dimensional change (i.e. radius and wall thickness) was observed between the control and the treated arteries at various pressure levels. These results imply that the luminal narrowing under vasospasm is not attributable to an irreversible organic change in the wall but to the constriction of vascular smooth muscle. The treated arteries are more distensible and have lower elastic moduli than the control arteries, possibly due to a change in the content of their connective tissues. These changes of the passive elastic properties of arterial walls after blood injection might be one of the factors affecting the development of cerebral vasospasm.

Basis for the altered arterial wall mechanics in the spontaneously hypertensive rat.

Carotid and tail arteries from 20-week-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were used to compare mechanics and biochemical properties. Measurements of pressure-diameter relations were made on isolated segments under conditions of active (145 mM K+) and passive (O mM Ca+2 and 2 mM EGTA) smooth muscle. Connective tissue, water and electrolyte contents, and extracellular water spaces were determined. Chemical data were also obtained from segments of thoracic aorta. The passive mechanics of arteries from the SHR were stiffer compared to those from WKY. Total connective tissue content (collagen + elastin) and collagen/elastin ratio were both smaller in the SHR arteries. Differences in the characteristics of the connective tissue matrix other than total content must exist in SHR and WKY arteries. Maximum values of active stress (force/area) developed by SHR arteries were larger and occurred at smaller values of wall strain compared to WKY arteries. The maximum reduction in wall diameter with smooth muscle activation was larger in the WKY arteries, but these constriction responses were better maintained at higher pressures by SHR arteries. Extracellular water space was lower in SHR arteries, while total water content was not different. The fraction of the wall of SHR arteries occupied by smooth muscle cells was larger than that of WKY arteries. When values of maximum active stress were normalized to the relative cell content, no difference was found for SHR and WKY carotids, but SHR tail arteries still produced a significantly larger active cell stress than WKY tail arteries. This suggests that intrinsic differences exist in the properties of smooth muscle cells of SHR and WKY tail arteries.

Arterial wall properties and dietary atherosclerosis in the racing greyhound

The effects of experimental (dietary) atherosclerosis on arteries from racing greyhounds were studied. Measurements of pressure and external diameter were made on islated carotid and iliac arteries under active (norepinephrine, 5 microgram/ml) and passive (zero Ca2+ and 2 mM EGTA) smooth muscle conditions. Iliac arteries from diet-fed animals demonstrated substantial intimal lesions, but the carotid arteries were usually grossly involved. Arteries from atherosclerotic animals were stiffer during passive conditions, with the iliac arteries having the greater changes. In iliac arteries from treated animals, collagen and elastin contents were decreased, and the collagen-to-elastin ratio was increased; in carotid arteries from treated animals, elastin content was increased and the collagen-to-elastin ratio was decreased. The maximum range of control of arterial wall mechanics by smooth muscle was diminished in treated iliacs but unchanged in carotids. Both force development and constriction responses associated with smooth muscle activation were diminished in treated iliacs but unchanged in treated carotids. Mechanical properties of series elastic elements in treated iliacs were stiffer, but treated carotids were unchanged.

Contribution of smooth muscle to arterial wall mechanics

The contribution of vascular smooth muscle to the mechanical properties of arteries can be quantitated using elastomeric and classical muscle concepts. Such analyses can be performed using pressure-diameter data obtained from a given specimen under conditions of active and passive muscle. The elastomeric approach represents arterial wall mechanics in terms of incremental elastic moduli and theoretical characteristic impedance, Z0. Activation of muscle produces a reduction in values of incremental modulus at almost all values of transmural pressure. Values of Z0 are increased at low pressure and decreased at high pressure following activation of muscle. In the muscle approach, the mechanics of arteries are quantitated in terms of active stress development and constriction responses as a function of muscle length and pressure, respectively. Active stress-muscle lenght and shortening-load relations obtained from arterial smooth muscle are qualitatively similar to those of other types of muscles. The length and load dependencies of these relations are what one would expect based on a sliding filament arrangement of contractile filaments.

Mechanical properties of arteries

Mechanical properties of arteries

Poststenotic dilatation: arterial wall mechanics in response to vibration.

A study of the relationship between the mechanical response of human iliac arteries subjected to sinusoidally varying dynamic pressures superimposed on a static pressure of 100 mm Hg (1mm Hg = 133 N/m2) and the development of arterial dilatation, with particular reference to poststenotic dilatation has been conducted. In 13 experiments, optical measurements of the amplitude of vessel wall movements in response to dynamic pressures of amplitude 5 mm Hg peak to peak indicated the presence of at least one, and at most four resonance peaks for frequencies in the mean range 0-100 Hz. Four specimens were vibrated at resonance and four at frequencies 15 Hz higher than resonance, in response to a dynamic pressure of 5 mm Hg peak to peak for 3 h. All specimens exhibited some dilatation, the average percentage increase in diameter being in the range 0.22 to 0.42% per hour. In four additional experiments, the dynamic pressure was doubled at constant frequency. This resulted in an increased amplitude of vibration and additional dilatation at an increased rate. It is concluded that the dynamic stresses present in the vessel influence the rate of dilatation.

Arterial wall mechanics and composition and the effects of smooth muscle activation.

A comparison of passive mechanics and the effects of smooth muscle (SM) activation has been made in canine carotid and iliac arteries. Measurements of external diameter and axial force were made on isolated cylindrical segments in response to internal pressure variations. Data were obtained during maximal norepinephrine (NE) and potassium (K) activation, and following metabolic inhibition of SM. These data were used to determine wall tangential stress-strain relations. The maximum increase in wall stress after K and after NE was greater for the iliacs and occurred at smaller values of wall strain. Passive stress-strain curves for the iliacs were likewise shifted to smaller strains, suggesting an important role of passive wall elements in setting the length of contractile elements. Diameter responses to K at low values of pressure were the same for iliacs and carotids, but were better maintained at higher pressure levels for the iliacs. Similar findings were found for iliac responses to NE and K. The results suggest that at low values of wall stress, active diameter responses are not strongly dependent on the maximum isometric stress development. However, higher pressure-diameter responses are also determined by the force-generating capacity of SM.

Age-related changes in the mechanics of the aorta and pulmonary artery of man.

Age-related changes in the mechanics of the aorta and pulmonary artery of man.

Chemical and kinetic analyses of sodium distribution in canine lingual artery.

ARTICLESChemical and kinetic analyses of sodium distribution in canine lingual arteryAW Jones, and ML SwainAW Jones, and ML SwainPublished Online:01 Nov 1972https://doi.org/10.1152/ajplegacy.1972.223.5.1110MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByVascular smooth muscle response to ouabain. Relation of tissue Na+ to the contractile response.Circulation Research, Vol. 73, No. 6Effects of hypertension and its reversal on canine arterial wall properties.Hypertension, Vol. 12, No. 3Sodium 22+ washout from cultured rat cellsJournal of Cellular Physiology, Vol. 129, No. 1Direct measurement of sodium influx in vascular smooth muscle. Stimulation by aldosterone.Hypertension, Vol. 7, No. 6_pt_1Uptake and efflux of calcium by canine coronary arteries and the action of adenosineBasic Research in Cardiology, Vol. 79, No. 5Electron probe analysis of sodium and other elements in hypertrophied and sodium-loaded smooth muscle.Circulation Research, Vol. 54, No. 3A simple ashing method for determination of Mg and Ca in laboratory animal feed and tissues.Journal of the American College of Nutrition, Vol. 2, No. 2Diffusional and compartmental models for tracer washout records of Na in dog carotidInternational Journal of Bio-Medical Computing, Vol. 13, No. 4Aldosterone infusion into the rat and dose-dependent changes in blood pressure and arterial ionic transport.Hypertension, Vol. 4, No. 3Evidence for an enhanced transmembrane sodium (Na+) gradient induced by aldosterone in the incubated rat tail artery.Hypertension, Vol. 4, No. 2Electrolyte Metabolism of the Arterial WallTime course of arterial wall changes with DOCA plus salt hypertension in the rat.Hypertension, Vol. 4, No. 1Kinetics of active sodium transport in aortas from control and deoxycorticosterone hypertensive rats.Hypertension, Vol. 3, No. 6Basis for the altered arterial wall mechanics in the spontaneously hypertensive rat.Hypertension, Vol. 3, No. 4Abnobmal Saphenous Vein Composition in Human Hypertension3 July 2009 | Clinical and Experimental Hypertension, Vol. 3, No. 1Content and Fluxes of Electrolytes1 January 2011Effects of sympathetic denervation or chronic reserpine on potassium (42K) and chloride (36Cl) efflux from guinea-pig vas deferensEuropean Journal of Pharmacology, Vol. 66, No. 1Multiexponential and multicompartmental approaches for analysis of tracer washout data from animal tissuesInternational Journal of Bio-Medical Computing, Vol. 10, No. 6Effects of pentobarbital, ethanol and morphine on subcellular localization of calcium and magnesium in brainBiochemical Pharmacology, Vol. 28, No. 20Computer simulation as an aid to incorporating diffusion effects into multicompartment models of Na exchange in tissuesAnnals of Biomedical Engineering, Vol. 6, No. 4Mediated transport and metabolism of lactate in rat aortaBiochimica et Biophysica Acta (BBA) - General Subjects, Vol. 541, No. 3Some remarks on compartmental analysis of uptake and washout dataLife Sciences, Vol. 22, No. 13-15Arterial Smooth Muscle MechanicsThe effect of norepinephrine on aortic 42K turnover during deoxycorticosterone acetate hypertension and antihypertensive therapy in the rat.Circulation Research, Vol. 41, No. 2Altered ion transport in aortic smooth muscle during deoxycorticosterone acetate hypertension in the rat.Circulation Research, Vol. 37, No. 3Extracellular Space MeasurementsEstimation of the State of Ions in Smooth MuscleAnalysis of Bulk-Diffusion-Limited Exchange of Ions in Smooth Muscle PreparationsLithium Substitution and the Distribution of Sodium in the Rat Tail ArteryCirculation Research, Vol. 34, No. 2Myocardial Mechanical Responses and Ionic Exchange in High-Sodium PerfusateCirculation Research, Vol. 34, No. 1Altered Ion Transport in Vascular Smooth Muscle from Spontaneously Hypertensive RatsCirculation Research, Vol. 33, No. 5 More from this issue > Volume 223Issue 5November 1972Pages 1110-1118 Copyright & PermissionsCopyright © 1972 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1972.223.5.1110PubMed4265952History Published online 1 November 1972 Published in print 1 November 1972 Metrics

Contractile response of vascular smooth muscle of renal hypertensive rats.

Contractile response of vascular smooth muscle of renal hypertensive rats.

Changes in connective tissue colloidal charge density with atherosclerosis and age.

ARTICLESChanges in connective tissue colloidal charge density with atherosclerosis and ageSP Porterfield, TB Calhoon, and HS WeissSP Porterfield, TB Calhoon, and HS WeissPublished Online:01 Aug 1968https://doi.org/10.1152/ajplegacy.1968.215.2.324MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited BySwelling of interlamellar GAGs/PGs as an initiation mechanism for aortic dissection: constitutive modeling and numerical simulations27 July 2022 | Mechanics of Soft Materials, Vol. 4, No. 1Intramural Glycosaminoglycans Distribution vs. Residual Stress in Porcine Ascending Aorta: a Computational StudyComputational modelling suggests good, bad and ugly roles of glycosaminoglycans in arterial wall mechanics and mechanobiology6 August 2014 | Journal of The Royal Society Interface, Vol. 11, No. 97Biomechanical roles of medial pooling of glycosaminoglycans in thoracic aortic dissection15 March 2013 | Biomechanics and Modeling in Mechanobiology, Vol. 13, No. 1Possible Mechanical Roles of Glycosaminoglycans in Thoracic Aortic Dissection and Associations with Dysregulated Transforming Growth Factor-�Journal of Vascular Research, Vol. 50, No. 1Continuum Modeling of Biological Tissue Growth by Cell Division, and Alteration of Intracellular Osmolytes and Extracellular Fixed Charge Density1 September 2009 | Journal of Biomechanical Engineering, Vol. 131, No. 10Heterogeneous transmural proteoglycan distribution provides a mechanism for regulating residual stresses in the aortaEvren U. Azeloglu, Michael B. Albro, Vikrum A. Thimmappa, Gerard A. Ateshian, and Kevin D. Costa1 March 2008 | American Journal of Physiology-Heart and Circulatory Physiology, Vol. 294, No. 3On the theory of reactive mixtures for modeling biological growth6 January 2007 | Biomechanics and Modeling in Mechanobiology, Vol. 6, No. 6Histochemical study on the glycosaminoglycans (acid mucopolysaccharides) of the human coronary arteriesActa Histochemica, Vol. 59, No. 2Respiration of the avian aorta in relation to spontaneous atherosclerosisComparative Biochemistry and Physiology Part A: Physiology, Vol. 38, No. 3Histochemical Studies on the Onset of Chronic LesionsProgress in Histochemistry and Cytochemistry, Vol. 2, No. 2Studies on the age-related changes occurring in human cerebral arteriesAtherosclerosis, Vol. 11, No. 3 More from this issue > Volume 215Issue 2August 1968Pages 324-329 Copyright & PermissionsCopyright © 1968 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1968.215.2.324PubMed5665163History Published online 1 August 1968 Published in print 1 August 1968 Metrics