Different biomechanical properties of medial and adventitial layers of thoracic aorta in Wistar-Kyoto and spontaneously hypertensive rats

Han, Weiqing; Chen, Jing; Wu, Lin‐Sheng; Zhu, Dongsheng; Gao, Pingjin

doi:10.1038/aps.2010.121

Cited by 9 publications

(16 citation statements)

References 27 publications

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“…For example, it contributes to the E high but not E low parameters in WKY and SHR strains (19). Our study focused on medial characteristics; however, physical separation and tensile testing of the adventitia from the media of the aortic ring, such as that conducted by Han et al (19), would quantify whether mechanical differences at high stress are due to adventitial or medial changes. The adventitia also plays a signaling role causing medial smooth muscle hypertrophy (30) and can regulate vascular inflammation (54), which can ultimately affect arterial stiffness.…”

Section: Discussionmentioning

confidence: 93%

Opposing changes in thoracic and abdominal aortic biomechanical properties in rodent models of vascular calcification and hypertension

Ameer

Salman

Avolio

et al. 2014

American Journal of Physiology-Heart and Circulatory Physiology

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This study investigated the effects of hypertension on regional aortic biomechanical and structural properties in three rat models of vascular calcification: the hypertensive Lewis polycystic kidney (LPK; n = 13) model of chronic kidney disease, spontaneously hypertensive rats (SHRs; n = 12), and calcification in normotensive Lewis rats induced by vitamin D3 and nicotine (VDN; n = 8). Lewis and Wistar-Kyoto rats were controls. Thoracic and abdominal aortic stiffness parameters were assessed by tensile testing. In models where aortic stiffness differences compared with controls existed in both thoracic and abdominal segments, an additional cohort was quantified by histology for thoracic and abdominal aortic elastin, collagen, and calcification. LPK and VDN animals had higher thoracic breaking strain than control animals (P < 0.01 and P < 0.05, respectively) and lower energy absorption within the tensile curve of the abdominal aorta (P < 0.05). SHRs had a lower abdominal breaking stress than Wistar-Kyoto rats. LPK and VDN rats had more elastic lamellae fractures than control rats (P < 0.001), which were associated with calcium deposition (thoracic R = 0.37, P = 0.048; abdominal: R = 0.40, P = 0.046). LPK rats had higher nuclear density than control rats (P < 0.01), which was also evident in the thoracic but not abdominal aorta of VDN rats (P < 0.01). In LPK and VDN rats, but not in control rats, media thickness and cross-sectional area were at least 1.5-fold greater in thoracic than abdominal regions. The calcification models chronic kidney disease and induced calcification in normotension caused differences in regional aortic stiffness not seen in a genetic form of hypertension. Detrimental abdominal aortic remodeling but lower stiffness in the thoracic aorta with disease indicates possible compensatory mechanisms in the proximal aorta.

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Section: Discussionmentioning

confidence: 93%

Opposing changes in thoracic and abdominal aortic biomechanical properties in rodent models of vascular calcification and hypertension

Ameer

Salman

Avolio

et al. 2014

American Journal of Physiology-Heart and Circulatory Physiology

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“…The comparative effect of the intimal and adventitial layers on arterial biomechanics control, in basal and altered conditions, remains to be elucidated. This study aimed (1) to characterize the arterial conduit (CF) and buffering (distensibility) function of the iliac arteries in in vivo animals, in which the intimal and adventitial layers were removed; (2) to determine the effects of intra-aortic ballon pumping (IABP) on simultaneously de-adventitialized (DA) and de-endothelialized (DE) iliac arteries before and after induced heart failure.…”

Section: Purposementioning

confidence: 99%

“…

Purpose The comparative effect of the intimal and adventitial layers on arterial biomechanics control, in basal and altered conditions, remains to be elucidated. This study aimed (1) to characterize the arterial conduit (CF) and buffering (distensibility) function of the iliac arteries in in vivo animals, in which the intimal and adventitial layers were removed; (2) to determine the effects of intra-aortic ballon pumping (IABP) on simultaneously de-adventitialized (DA) and de-endothelialized (DE) iliac arteries before and after induced heart failure.

Methods Pressure and diameter signals were measured in the iliac arteries of sheep (n = 7) in which the adventitial and intima layer were removed. Intra-aortic balloon pump (IABP) assistance was used in a control state and after heart failure induction.

Results Both DE and DA determined significant changes in arterial diameter, distensibility and CF.

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mentioning

confidence: 99%

Comparative in Vivo Analysis of the Role of the Adventitia and the Endothelium on Arterial Mechanical Function: Relevance for Aortic Counterpulsation

et al. 2017

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“…The adventitial layer was, therefore, presumed to play a role in vascular biomechanical properties, but not contribute to passive mechanics at physiological load. 9 Ang II has been targeted more than once as a potential contributor to adventitial remodeling. In a model of transverse aortic constriction, extensive vascular remodeling was reported.…”

Section: Lehoux Adventures In the Adventitia 837mentioning

confidence: 99%

Adventures in the Adventitia

Lehoux

2016

Hypertension

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A rterial hypertension, by definition, imparts accrued strain on the vascular wall. This in turn elicits counteracting radial and tangential forces, driving transformations in the vessel wall that aim to accommodate the new conditions and to ultimately restore basal levels of tensile stress. Vascular accumulation of type I, III, and IV collagen in hypertensive patients and in animal models of hypertension effectively counteracts the distending force of blood pressure, but at length it also results in increased vascular stiffness. Clinically, vascular stiffness translates to greater pulse pressure, which is an independent predictor of mortality in patients with end-stage renal failure, hypertension, and diabetes mellitus and in older individuals. 1Conventionally, hypertensive vascular remodeling has been ascribed essentially to smooth muscle cell hypertrophy and amplified collagen synthesis by these cells. However, there is a growing body of knowledge that points to the adventitia as a significant and perhaps even the principal contributor to pathological hypertensive remodeling. In this issue of Hypertension, Bersi et al 2 provide convincing evidence that when it comes to stiffness and stress, we ought to take a closer look at the outer aspect of the arterial wall.Bersi et al 2 found that a 2-or 4-week infusion of angiotensin II (Ang II) in mice, augmenting blood pressure significantly and persistently, resulted in arteries that are both less distensible and less extensible, associated with reduced elastic energy storage. The increased stiffness was attributed essentially to the thickened wall structure. Although smooth muscle hypertrophy and greater deposition of collagen within the lamellae were observed in the aortas of hypertensive mice, the most striking difference between these animals and their normotensive counterparts was in the extent of adventitial fibrillar collagen accumulation. The adventitial collagen was thus considered to bear a greater amount of load under hypertensive conditions compared with normotensive conditions (Figure).These results are reminiscent of and lend strong support to observations made by the same group using a model of carotid artery banding in mice. Both morphological and biaxial mechanical responses were recorded after 6 weeks. In banded arteries, increased pulse pressure and systolic pressure were found to correlate with arterial thickening, adventitial collagen accumulation, as well as decreased axial stretch. 3Moreover, although the media contained a greater fraction of type III collagen, the adventitia contained instead a greater proportion of type I collagen.This latter point is of fundamental importance because there are key differences between medial and adventitial collagen that bear mentioning. For one thing, type III collagen is more extensible than the type I collagen. 4 It forms a relatively elastic network that stores kinetic energy. Perhaps because of this characteristic, the structure of medial collagen changes at the onset of biaxial loading in porcine arteri...

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Different biomechanical properties of medial and adventitial layers of thoracic aorta in Wistar-Kyoto and spontaneously hypertensive rats

Cited by 9 publications

References 27 publications

Opposing changes in thoracic and abdominal aortic biomechanical properties in rodent models of vascular calcification and hypertension

Opposing changes in thoracic and abdominal aortic biomechanical properties in rodent models of vascular calcification and hypertension

Comparative in Vivo Analysis of the Role of the Adventitia and the Endothelium on Arterial Mechanical Function: Relevance for Aortic Counterpulsation

Adventures in the Adventitia

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