A constitutive modeling interpretation of the relationship among carotid artery stiffness, blood pressure, and age in hypertensive subjects

Aging has a profound influence on arterial wall structure and function. We have previously reported the relationship among pulse wave velocity, age, and blood pressure in hypertensive subjects. In the present study, we aimed for a quantitative interpretation of the observed changes in wall behavior with age using a constitutive modeling approach. We implemented a model of arterial wall biomechanics and fitted this to the group-averaged pressure-area ( P-A) relationship of the “young” subgroup of our study population. Using this model as our take-off point, we assessed which parameters had to be changed to let the model describe the “old” subgroup’s P-A relationship. We allowed elastin stiffness and collagen recruitment parameters to vary and adjusted residual stress parameters according to published age-related changes. We required wall stress to be homogeneously distributed over the arterial wall and assumed wall stress normalization with age by keeping average “old” wall stress at the “young” level. Additionally, we required axial force to remain constant over the cardiac cycle. Our simulations showed an age-related shift in pressure-load bearing from elastin to collagen, caused by a decrease in elastin stiffness and a considerable increase in collagen recruitment. Correspondingly, simulated diameter and wall thickness increased by about 20 and 17%, respectively. The latter compared well with a measured thickness increase of 21%. We conclude that the physiologically realistic changes in constitutive properties we found under physiological constraints with respect to wall stress could well explain the influence of aging in the stiffness-pressure-age pattern observed.

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Effect of chronic ANG I-converting enzyme inhibition on aging processes. II. Large arteries

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1994.267.1.r124 ◽

1994 ◽

Vol 267 (1) ◽

pp. R124-R135 ◽

Cited By ~ 19

Author(s):

J. B. Michel ◽

D. Heudes ◽

O. Michel ◽

P. Poitevin ◽

M. Philippe ◽

...

Keyword(s):

Blood Pressure ◽

Smooth Muscle ◽

Arterial Wall ◽

Left Ventricular ◽

Structure And Function ◽

Wall Structure ◽

Large Artery ◽

Converting Enzyme ◽

Wall Stiffness ◽

And Function

The consequences of hypertension and aging on cardiovascular structure and function are reputed to be similar, suggesting that blood pressure plays a role in the aging process. However, the exact relationship between aging, blood pressure, and the arterial structure-function relationship has not been demonstrated. To test the effects of aging, renin-angiotensin system, and pressure on the arterial wall, 20 normotensive male WAG/Rij rats were killed at 6, 12, 24, and 30 mo of age and compared with similar groups treated with an angiotensin (ANG)-converting enzyme inhibitor (ACEI), perindopril. Arterial function was determined by a systemic hemodynamic study and by in situ measurement of carotid compliance. Arterial wall structure was determined by histomorphometric and biochemical methods. Aging did not significantly modify blood pressure, but ACE inhibition decreased blood pressure significantly from 6 to 30 mo. Plasma renin activity decreased with age and increased with ACEI. Plasma atrial natriuretic factor increased with age and was significantly decreased with ACEI. Absolute and relative left ventricular weight increased with age, and ACEI delayed these increases. Arterial wall stiffness increased with age, as shown by a significant decrease in systemic and local arterial compliance and by an increase in aortic characteristic impedance. The increase in carotid wall compliance after poisoning of smooth muscle contractile function (KCN) was greater in young (6- and 12-mo old) than in old (24- and 30-mo old) rats. Chronic ACEI treatment increased basal carotid compliance values slightly and did not change KCN carotid compliance. The aortic and carotid luminal size increased regularly with age. Aging was associated without any change in absolute elastin content. In contrast, collagen content increased with aging. Aging was also associated with an increase in medial thickness. Medial thickening was mainly due to smooth muscle hypertrophy. Aging was associated with intimal proliferation, which became progressively thicker and collagen rich. ACEI treatment did not prevent aortic lumen enlargement but significantly postponed the increase in medial and intimal thickening. Biochemical determinations of the aortic wall components confirmed the morphometric data. In conclusion, the age-dependent large artery enlargement and stiffening were observed both in normotensive rats and in those rats whose blood pressure was lowered by ACEI. This suggests that aging and blood pressure affect arterial wall structure and function by different mechanisms.

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Experimental Investigation of Mechanical and Structural Inhomogeneity in Bovine Carotid Arteries

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-192480 ◽

2008 ◽

Cited By ~ 2

Author(s):

Lucas H. Timmins ◽

Christopher A. Evagora ◽

James E. Moore ◽

Stephen E. Greenwald

Keyword(s):

Arterial Wall ◽

Constitutive Models ◽

Wall Structure ◽

Histological Structure ◽

Energy Functions ◽

Arterial Structure ◽

Wall Deformation ◽

And Function ◽

Strain Energy Functions ◽

The Relationship

Many constitutive models have been proposed to assess arterial mechanical behavior. Most, however, are largely phenomenological and lack a detailed consideration of arterial wall constituents and the manner in which mechanical loads are distributed amongst them. Recently, strain energy functions (SEF) that consider histological evidence about arterial wall structure have been developed [1,2]. These SEFs incorporate fiber bundle orientation and consider the relative proportions of the major wall constituents to offer a better description of arterial wall deformation. Including histological structure and its affects on arterial elasticity could provide a better understanding of the relationship between arterial structure and function. Further shortcomings in arterial modeling include the assumption that the arterial wall is a homogeneous structure, when in fact it is well known to be a non homogenous, although there are notable exceptions [3,4].

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Morphological and Biochemical Features Affecting the Antithrombotic Properties of the Aorta in Adult Rabbits and Rabbit Pups

Thrombosis and Haemostasis ◽

10.1055/s-0037-1615116 ◽

1998 ◽

Vol 79 (05) ◽

pp. 1034-1040 ◽

Cited By ~ 17

Author(s):

E. Nitschmann ◽

L. Berry ◽

S. Bridge ◽

M. W. C. Hatton ◽

M. Richardson ◽

...

Keyword(s):

Electron Microscopy ◽

Gel Electrophoresis ◽

Arterial Wall ◽

Structure And Function ◽

Wall Structure ◽

Matrix Structure ◽

Antithrombotic Activity ◽

Antithrombin Activity ◽

And Function ◽

Biochemical Features

SummaryWe hypothesised that there are important physiologic differences in arterial wall structure and function with respect to antithrombotic activity in the very young (pre-puberty) compared to adults. Electron microscopy, gel electrophoresis, and activity assays were used to examine differences in aorta structure and function comparing prepubertal rabbits (pups) to adult rabbits. Differences in endothelial function, extracellular matrix structure, proteoglycan (PG) distribution and glycosaminoglycan (GAG) content and function were shown. In both intima and media, total PG, chondroitin sulfate (CS) PG and heparan sulfate (HS) PG content were significantly increased in pups compared to adult rabbits. These findings corresponded to increased concentrations by mass analyses of CS GAG and DS GAG in aortas from pups. There was also a significant increase in antithrombin activity in pups due to HS GAG. In conclusion, differences in both structure and antithrombin activity of aortas from pups compared to adult rabbits suggest that young arteries may have greater antithrombotic potential that is, at least in part, related to increased HS GAG.

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Blood pressure-induced physiological strain variability modulates wall structure and function in aorta rings

Physiological Measurement ◽

10.1088/1361-6579/aae65f ◽

2018 ◽

Vol 39 (10) ◽

pp. 105014 ◽

Cited By ~ 3

Author(s):

Jasmin Imsirovic ◽

Erzsébet Bartolák-Suki ◽

Samer Bou Jawde ◽

Harikrishnan Parameswaran ◽

Béla Suki

Keyword(s):

Blood Pressure ◽

Structure And Function ◽

Wall Structure ◽

Physiological Strain ◽

And Function ◽

Strain Variability

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The CCL7-CCL2-CCR2 Axis Regulates Age-Related Alterations in ADSCs

10.21203/rs.3.rs-390571/v1 ◽

2021 ◽

Author(s):

Keya Li ◽

Guiying Shi ◽

Xuepei Lei ◽

Yiying Huang ◽

Xinyue Li ◽

...

Keyword(s):

Autologous Transplantation ◽

Hippo Signaling ◽

Related Disorder ◽

Promising Strategy ◽

Age Related ◽

Minimum Number ◽

And Function ◽

The Relationship ◽

Harmful Effects

Abstract Background and ObjectivesAdipose-tissue derived stem cells (ADSCs) autologous transplantation have been a promising strategy for aging-related disorder. But the relationship between ADSCs senescence and organismal aging were still no consistent conclusions. Toward this end, we analyzed the senescence properties of ADSCs from different age donors to furthermore understand the differences of cells between young and senile donors and verify the influence of organismal aging on the proliferation and function of ADSCs in vitro, providing the theoretical basis for the clinical application of autologous ADSCs transplantation.Methods and ResultsWe detected the characteristics, function, gene expression, apoptosis, cell cycle, SA-β-gal staining, and transcription features of ADSCs from 1-month mice and 20-month mice. ADSCs from old donors had some senescence-associated changes with less ability to proliferation than ADSCs from 1-month mice. Differentiation ability, cell surface markers, and SA-β-Gal staining did not differ across donor age, while cells exhibit a more remarkable age-related changes through continuous passages. According to the results of transcriptome analysis, the CCL7-CCL2-CCR2 axis and Hippo signaling pathway would be considered as its possible mechanisms. ConclusionsOur study reveals that ADSCs from old donors have some age-related alterations. The CCL7-CCL2-CCR2 which lies behind this change would be a potential target for gene therapy to reduce harmful effects of ADSCs from old donors. To make autologous transplantation work better, we would recommend that ADSCs should be cryopreserved in youth with minimum number of passages.

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Abstract TP451: Age-associated Changes in the Structure and Biomechanical Properties of Parenchymal Arterioles

Stroke ◽

10.1161/str.47.suppl_1.tp451 ◽

2016 ◽

Vol 47 (suppl_1) ◽

Author(s):

Janice M Diaz-Otero ◽

William F Jackson ◽

Anne M Dorrance

Keyword(s):

Blood Pressure ◽

Extracellular Matrix ◽

Wall Thickness ◽

Biomechanical Properties ◽

Wall Structure ◽

Collagen Deposition ◽

Artery Wall ◽

Wall Area ◽

Age Related ◽

Artery Remodeling

Arterial aging, a phenomenon that we do not fully understand, results in dysfunctional arteries. Age-associated changes in physiological and vascular functions increase the risk of cardiovascular disease. Aging results in peripheral artery remodeling, described as a change in artery size and wall structure. Age-related cerebral artery remodeling could increase the risk of stroke and vascular dementia particularly in situations where comorbidities, such as hypertension, are present. The effects of aging on the biomechanical properties of parenchymal arterioles (PAs) have not been characterized. PAs regulate perfusion of the cerebral microcirculation and are important in determining cerebrovascular resistance. We hypothesized that aging would decrease the lumen diameter, and increase the wall thickness and collagen deposition in PAs from C57Bl/6 mice. PAs were collected from 3-5 month (young; n=8) and 22-24 month (old; n=8) old male mice for assessment of structure by pressure myography. Data collected at 60mmHg are presented as mean ± SEM, young vs. old. Advanced age was associated with increased systolic blood pressure (126 ± 1 vs 145 ± 2mmHg). Aging did not significantly affect the outer (49 ± 5 vs 53 ± 3μm) or lumen (41 ± 5 vs 41 ± 2μm) diameter of the PAs (p > 0.05 for all comparisons). However, the PAs from older mice had increased wall thickness (4 ± 1 vs 6 ± 1μm), wall area (591 ± 96 vs 853 ± 101μm2), and wall-to-lumen ratio (0.10 ± 0.01 vs 0.13 ± 0.01) (p < 0.05 for all comparisons). Wall stress (302 ± 27 vs 220 ± 11 dynes/cm2) was reduced with age. Changes in artery wall structure have been associated with modifications in the components of the extracellular matrix such as collagen and calcium. The PAs from older mice had increased collagen deposition in the wall (427 ± 172 vs 2699 ± 442μm2; p < 0.05) but the number of arteries with calcium deposits was similar between groups (2 ± 1 vs 3 ± 1 positive vessels/area; p > 0.05). Our studies of geriatric mice with high blood pressure suggest that aging is associated with hypertrophic remodeling of the PAs that is accompanied by alterations in the extracellular matrix of the artery wall; these changes could increase the risk of cerebrovascular diseases.

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The Relationship between the 24 h Blood Pressure Variability and Carotid Intima-Media Thickness: A Compared Study

Computational and Mathematical Methods in Medicine ◽

10.1155/2014/303159 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 16

Author(s):

Huahua Xiong ◽

Dan Wu ◽

Xiaohong Tian ◽

Wan-Hua Lin ◽

Chunyue Li ◽

...

Keyword(s):

Blood Pressure ◽

Blood Pressure Variability ◽

Vascular System ◽

Large City ◽

Intima Media Thickness ◽

Carotid Intima Media Thickness ◽

Media Thickness ◽

Average Real Variability ◽

And Function ◽

The Relationship

Large blood pressure variability (BPV) will not only harm the target organ but also increase the possibility of the cardiovascular events. Since the damage of vascular system always leads to the alteration of the carotid wall, the structure and function of the carotid artery have been extensively examined in previous studies. In this work we conduct a study (60 subjects, aged 33–79) to evaluate the relationship between BPV and carotid intima-media thickness (IMT) in Shenzhen, which is one large city in the southern area of China. In our study, the blood pressure (BP) was collected using the 24 h ambulatory BP monitoring, and the BPV was evaluated using standard deviation (SD), coefficient of variation (CV), and average real variability (ARV) during 24 h, daytime and nighttime. All the IMT measurements are collected by ultrasound. The results show that both the daytime, and 24 h systolic BPV evaluated by three indices are positively associated with IMT. Among them, daytime systolic BPV evaluated with ARV is the best variable to represent the increasing of carotid IMT. In addition, after adjusting by age, sex, smoking, hypertension, and mean BP and PP values, 24 h diastolic BPV evaluated with SD also presents the favorable performance.

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The Relationship between Birthweight and Longitudinal Changes of Blood Pressure Is Modulated by Beta-Adrenergic Receptor Genes: The Bogalusa Heart Study

Journal of Biomedicine and Biotechnology ◽

10.1155/2010/543514 ◽

2010 ◽

Vol 2010 ◽

pp. 1-8 ◽

Cited By ~ 5

Author(s):

Wei Chen ◽

Sathanur R. Srinivasan ◽

D. Michael Hallman ◽

Gerald S. Berenson

Keyword(s):

Blood Pressure ◽

Adrenergic Receptor ◽

Low Birthweight ◽

Receptor Gene ◽

Bogalusa Heart Study ◽

Longitudinal Changes ◽

Age Related ◽

Heart Study ◽

Blacks And Whites ◽

The Relationship

This study examines the genetic influence ofβ-adrenergic receptor gene polymorphisms (β2-AR Arg16Gly andβ3-AR Trp64Arg) on the relationship of birthweight to longitudinal changes of blood pressure (BP) from childhood to adulthood in 224 black and 515 white adults, aged 21–47 years, enrolled in the Bogalusa Heart Study. Blacks showed significantly lower birthweight and frequencies ofβ2-AR Gly16 andβ3-AR Trp64 alleles and higher BP levels and age-related trends than whites. In multivariable regression analyses using race-adjusted BP and birthweight, low birthweight was associated with greater increase in age-related trend of systolic BP (standardized regression coefficientβ=−0.09,P=.002) and diastolic BP (β=−0.07,P=.037) in the combined sample of blacks and whites, adjusting for the first BP measurement in childhood, sex, age, and gestational age. Adjustment for the current body mass index strengthened the birthweight-BP association. Importantly, the strength of the association, measured as regression coefficients, was modulated by the combination ofβ2-AR andβ3-AR genotypes for systolic (P=.042for interaction) and diastolic BP age-related trend (P=.039for interaction), with blacks and whites showing a similar trend in the interaction. These findings indicate that the intrauterine programming of BP regulation later in life depends onβ-AR genotypes.

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