A comparison of age-related changes in axial prestretch in human carotid arteries and in human abdominal aorta

This study aimed to elucidate the effect of aging on shear-mediated dilation of the common and internal carotid arteries (CCA and ICA, respectively). Hypercapnia-induced shear-mediated dilation in the CCA and ICA were assessed in 10 young (5 women and 5 men, 23 ± 1 yr) and 10 older (6 women/4 men, 68 ± 1 yr) healthy adults. Shear-mediated dilation was induced by two levels of hypercapnia (target end-tidal Pco2, +5 and +10 mmHg from individual baseline values) and was calculated as the percent rise in peak diameter from baseline diameter. There were no differences in shear-mediated dilation between young and older adults in either artery under lower levels of hypercapnia (CCA: 2.8 ± 0.6 vs. 2.0 ± 0.3%, P = 0.35; ICA: 4.6 ± 0.8 vs 3.6 ± 0.4%, P = 0.37). However, shear-mediated dilation in response to higher levels of hypercapnia was attenuated in older compared with young adults in the ICA (4.5 ± 0.5 vs. 7.9 ± 1.2%, P < 0.01) but not in the CCA (3.7 ± 0.6 vs. 4.5 ± 0.8%, P = 0.35). Shear-mediated dilation was significantly correlated to the percent change in shear rate in the ICA (young: r = 0.55, P = 0.01; older: r = 0.49, P = 0.03) but not in the CCA in either young or older adults (young: r = −0.30, P = 0.90; older: r = 0.16, P = 0.50). These data indicate that aging attenuates shear-mediated dilation of the ICA in response to higher levels of hypercapnia, and shear rate is an important stimulus for hypercapnic vasodilation of the ICA in both young and older adults. The present results may provide insights into age-related changes in the regulation of cerebral circulation in healthy adults. NEW & NOTEWORTHY We explored the effect of aging on shear-mediated dilation in the common and internal carotid arteries (CCA and ICA, respectively) in healthy adults. Our findings suggest that 1) aging attenuates shear-mediated dilation of the ICA but not the CCA and 2) shear rate is an important stimulus for hypercapnic vasodilation of the ICA in young and older adults. These findings may provide insights into the age-related changes in cerebrovascular regulation of healthy adults.

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Correlation Between Pulpal and Carotid Arteries Blood Flow in Two Age Groups

Stomatoloski glasnik Srbije ◽

10.1515/sdj-2015-0014 ◽

2015 ◽

Vol 62 (3) ◽

pp. 130-136

Author(s):

Bojan Dželetović ◽

Nikola Aleksić ◽

Djurica Grga ◽

Tatjana Savić-Stanković ◽

Ivana Milanović ◽

...

Keyword(s):

Blood Flow ◽

Carotid Artery ◽

Carotid Arteries ◽

Middle Age ◽

External Carotid Artery ◽

External Carotid ◽

Artery Blood Flow ◽

Pulp Tissue ◽

Age Related ◽

Age Related Changes

Abstract Introduction Vascular network of dental pulp is supplied through common and external carotid artery and terminal dental branches that supply each pulp tissue. Age related changes of pulp tissue influence pulpal vascularization as well. The aim of this study was to compare and correlate pulpal and common and external carotid artery blood flow in young and middle age individuals of general population. Material and Methods Two groups of 10 participants were included in the study, young (20-25 years) and middle age (50-55 years) group. Pulpal blood flow (PBF) measurements on intact right and left upper central incisors were performed using laser Doppler flowmetry (LDF) method. Carotid arteries blood flow was assessed using carotid ultrasonography. Results PBF levels were significantly higher in young (3.11±0.67 and 3.46±1.11, right and left upper central incisors, respectively) compared to middle age (1.93±0.47 and 2.30±0.64, right and left upper central incisors, respectively) participants (independent sample t test; p<0.05). There was no correlation between common and external carotid artery blood flow and upper central incisors PBF in young as well as middle age participants, for right or left side. Conclusion Absence of correlation between carotid arteries blood flow and PBF suggests that reduced PBF in middle age participants was probably not due to reduced blood supply from carotid arteries but it was result of age related changes at the level of pulpal blood vessels.

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Age Dependency of the Biaxial Biomechanical Behavior of Human Abdominal Aorta

Journal of Biomechanical Engineering ◽

10.1115/1.1824121 ◽

2004 ◽

Vol 126 (6) ◽

pp. 815-822 ◽

Cited By ~ 108

Author(s):

Jonathan P. Vande Geest ◽

Michael S. Sacks ◽

David A. Vorp

Keyword(s):

Experimental Data ◽

Abdominal Aorta ◽

Energy Function ◽

Strain Energy ◽

Strain Energy Function ◽

Infrarenal Aorta ◽

Biomechanical Behavior ◽

Age Related ◽

Human Abdominal Aorta ◽

Group 1

Background: The biomechanical behavior of the human abdominal aorta has been studied with great interest primarily due to its propensity to develop such maladies as atherosclerotic occlusive disease, dissections, and aneurysms. The purpose of this study was to investigate the age-related biaxial biomechanical behavior of human infrarenal aortic tissue. Methods of Approach: A total of 18 samples (13 autopsy, 5 organ donor) were harvested from patients in each of three age groups: Group 1 (<30years old, n=5), Group 2 (between 30 and 60 years old, n=7), and Group 3 (>60years old, n=6). Each specimen was tested biaxially using a tension-controlled protocol which spanned a large portion of the strain plane. Response functions fit to experimental data were used as a tool to guide the appropriate choice of the strain energy function W. Results: Under an equibiaxial tension of 120 N/m, the average peak stretch values in the circumferential direction for Groups 1, 2, and 3 were mean±SD1.46±0.07,1.15±0.07, and 1.11±0.06, respectively, while the peak stretch values in the longitudinal direction were 1.41±0.03,1.19±0.11, and 1.10±0.04, respectively. There were no significant differences between the average longitudinal and circumferential peak stretch within each group p>0.1, but both of these values were significantly less p<0.001 for Groups 2 and 3 when compared to Group 1. Patients in Group 1 were modeled using a polynomial strain energy function W, while patients in Groups 2 and 3 were modeled using an exponential form of W, suggesting an age-dependent shift in the mechanical response of this tissue. Conclusion: The biaxial tensile testing results reported here are, to our knowledge, the first given for the human infrarenal aorta and reinforce the importance of determining the functional form of W from experimental data. Such information may be useful for the clinician or researcher in identifying key changes in the biomechanical response of abdominal aorta in the presence of an aneurysm.

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Age-related changes in the abdominal aorta shown by computed tomography

Clinical Radiology ◽

10.1016/s0009-9260(84)80228-7 ◽

1984 ◽

Vol 35 (1) ◽

pp. 33-37 ◽

Cited By ~ 56

Author(s):

A.K. Dixon ◽

J.P. Lawrence ◽

J.R.A. Mitchell

Keyword(s):

Computed Tomography ◽

Abdominal Aorta ◽

Age Related ◽

Age Related Changes

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Age-related increase in wall stress of the human abdominal aorta: An in vivo study

Journal of Vascular Surgery ◽

10.1016/j.jvs.2005.07.010 ◽

2005 ◽

Vol 42 (5) ◽

pp. 926-931 ◽

Cited By ~ 33

Author(s):

Håkan Åstrand ◽

Åsa Rydén-Ahlgren ◽

Tomas Sandgren ◽

Toste Länne

Keyword(s):

Abdominal Aorta ◽

Wall Stress ◽

In Vivo Study ◽

Age Related ◽

Human Abdominal Aorta ◽

Related Increase

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In vivo estimation of the contribution of elastin and collagen to the mechanical properties in the human abdominal aorta: effect of age and sex

Journal of Applied Physiology ◽

10.1152/japplphysiol.00579.2010 ◽

2011 ◽

Vol 110 (1) ◽

pp. 176-187 ◽

Cited By ~ 47

Author(s):

H. Åstrand ◽

J. Stålhand ◽

J. Karlsson ◽

M. Karlsson ◽

B. Sonesson ◽

...

Keyword(s):

Mechanical Properties ◽

Abdominal Aorta ◽

Aortic Wall ◽

Human Aorta ◽

Material Parameters ◽

Age Related ◽

Human Abdominal Aorta ◽

Effect Of Age

The mechanical properties of the aorta affect cardiac function and are related to cardiovascular morbidity/mortality. This study was designed to evaluate the isotropic (mainly elastin, elastiniso) and anisotropic (mainly collagen, collagenani) material parameters within the human aorta in vivo. Thirty healthy men and women in three different age categories (23–30, 41–54, and 67–72 yr) were included. A novel mechanical model was used to identify the mechanical properties and the strain field with aid of simultaneously recorded pressure and radius in the abdominal aorta. The magnitudes of the material parameters relating to both the stiffness of elastiniso and collagenani were in agreement with earlier in vitro studies. The load-bearing fraction attributed to collagenani oscillated from 10 to 30% between diastolic and systolic pressures during the cardiac cycle. With age, stiffness of elastiniso increased in men, despite the decrease in elastin content that has been found due to elastolysis. Furthermore, an increase in stiffness of collagenani at high physiological pressure was found. This might be due to increased glycation, as well as changed isoforms of collagen in the aortic wall with age. A marked sex difference was observed, with a much less age-related effect, both on elastiniso and collagenani stiffness in women. Possible factors of importance could be the effect of sex hormones, as well as differing collagen isoforms, between the sexes.

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