Assessment of elastin and collagen contribution to aortic elasticity in conscious dogs.

The elastic behavior of total elastin (EE) and collagen (EC) and the recruitment of collagen fibers (FC) supporting wall stress at a given transmural pressure level were assessed in seven conscious dogs using descending thoracic aortic pressure (microtransducer) and diameter (sonomicrometer) measurements. Stress-strain relationships values calculated at control and during bolus administration of angiotensin and nitroglycerin enabled quantification of angiotensin and nitroglycerin enabled quantification of elastic moduli of elastin (EE = 4.868 +/- 1.753 x 10(6) dyn/cm2; means +/- SD) and collagen (EC = 1,306 +/- 637 x 10(6) dyn/cm2) according to a biphasic model of elastin and collagen parallel arrangement. The FC was found to be 6.1 +/- 2.6% at a pressure level of 118 +/- 16 mmHg. Values for EE and EC were similar to those reported in in vitro studies and showed scarce variability. This approach provides a quantitative evaluation of elastin and collagen moduli in conscious animals and also permits the evaluation of FC, which may be of interest in studies of connective tissue diseases involving the aortic wall.

[1]  E de Forteza,et al.  Real-time pressure-volume diagrams for the evaluation of ventricular function. , 1986, Journal of biomedical engineering.

[2]  A. C. Burton,et al.  The reason for the shape of the distensibility curves of arteries. , 1957, Canadian journal of biochemistry and physiology.

[3]  H. P. Pieper,et al.  Responses of aortic smooth muscle studied in intact dogs. , 1969, The American journal of physiology.

[4]  M Pagani,et al.  Measurement of multiple simultaneous small dimensions and study of arterial pressure-dimension relations in conscious animals. , 1978, The American journal of physiology.

[5]  G. Ordway,et al.  Regional Volume Distensibility of Canine Thoracic Aorta During Moderate Treadmill Exercise , 1988, Circulation research.

[6]  H. Aars Diameter and elasticity of the ascending aorta during infusion of noradrenaline. , 1971, Acta physiologica Scandinavica.

[7]  A. Rovick,et al.  Influence of vascular smooth muscle on contractile mechanics and elasticity of arteries. , 1969, The American journal of physiology.

[8]  A. C. Burton Relation of structure to function of the tissues of the wall of blood vessels. , 1954, Physiological reviews.

[9]  D. Stone,et al.  Changes in smooth muscle tone influence characteristic impedance of the aorta. , 1984, The American journal of physiology.

[10]  D. R. Gross,et al.  Segmental volume distensibility of the canine thoracic aorta in vivo. , 1988, Cardiovascular research.

[11]  M Pagani,et al.  Effects of Age on Aortic Pressure‐Diameter and Elastic Stiffness‐Stress Relationships in Unanesthetized Sheep , 1979, Circulation research.

[12]  G. L’italien,et al.  Noninvasive measurements of nonlinear arterial elasticity. , 1986, The American journal of physiology.

[13]  Lysle H. Peterson,et al.  Mechanical Properties of Arteries in Vivo , 1960 .

[14]  B. S. Gow,et al.  Measurement of Viscoelastic Properties of Arteries in the Living Dog , 1968, Circulation research.

[15]  S. Ling,et al.  The mechanics of corrugated collagen fibrils in arteries. , 1977, Journal of biomechanics.

[16]  R N Vaishnav,et al.  Nonlinear anisotropic elastic properties of the canine aorta. , 1972, Biophysical journal.

[17]  H. P. Pieper,et al.  Effect of acute volume loading on aortic smooth muscle activity in intact dogs. , 1980, The American journal of physiology.

[18]  Constricting and Stiffening Action of Atropine on Aortic Response to Angiotensin in Dogs , 1988, Hypertension.

[19]  D Franklin,et al.  Telemetry of left ventricular diameter and pressure measurements from unrestrained animals. , 1974, Journal of applied physiology.

[20]  H. Bader Importance of the gerontology of elastic arteries in the development of essential hypertension. , 1983, Clinical physiology and biochemistry.

[21]  M. Yano,et al.  Effect of diltiazem on aortic pressure-diameter relationship in dogs. , 1989, The American journal of physiology.