Changes in Vascular Viscoelasticity Caused by Smooth Muscle Cell Tone and Pressurization Frequency

Author(s):  
Ryan J. DeWall ◽  
Naomi C. Chesler

The cushioning and conduit functions of large arteries allow the body to efficiently circulate blood and perfuse organs. These functions can be characterized by quantifying the viscoelastic properties of arteries. In this study, we investigated the effects of smooth muscle cell (SMC) tone and pressurization frequency on vascular viscoelasticity using an isolated, perfused vessel test. We tested mouse carotid arteries in control, dilated (via sodium nitroprusside) and constricted (via the thromboxane receptor analogue U46619) states at 0.1, 1, 3, and 5 Hz with a pulse pressure from 90 to 120 mmHg. Dose response experiments were first performed in order to determine the optimal vasoconstrictor concentration to be used in frequency response experiments. Our results showed that energy dissipation was significantly higher and elasticity was significantly lower for vasoconstricted arteries. We also found that frequency significantly changed both energy dissipation and elasticity as the frequency was increased from 0.1 to 5 Hz. These results provide insights into the changes in vascular viscoelasticity caused by SMC tone and pressurization frequency, which have implications for vascular function in vivo.

2010 ◽  
Vol 298 (6) ◽  
pp. C1481-C1488 ◽  
Author(s):  
Xiaojun Liu ◽  
Yunhui Cheng ◽  
Jian Yang ◽  
Thomas J. Krall ◽  
Yuqing Huo ◽  
...  

It is well established that vascular smooth muscle cell (VSMC) apoptosis and proliferation are critical cellular events in a variety of human vascular diseases. However, the molecular mechanisms involved in controlling VSMC apoptosis and proliferation are still unclear. In the current study, we have found that programmed cell death 4 (PDCD4) is significantly downregulated in balloon-injured rat carotid arteries in vivo and in platelet-derived growth factor-stimulated VSMCs in vitro. Overexpression of PDCD4 via adenovirus (Ad-PDCD4) increases VSMC apoptosis in an apoptotic model induced by serum deprivation. In contrast, VSMC apoptosis is significantly decreased by knockdown of PDCD4 via its small interfering RNA. In the rat carotid arteries in vivo, VSMC apoptosis is increased by Ad-PDCD4. We have further identified that activator protein 1 is a downstream signaling molecule of PDCD4 that is associated with PDCD4-mediated effects on VSMC apoptosis. In addition, VSMC proliferation was inhibited by overexpression of PDCD4. The current study has identified, for the first time, that PDCD4 is an essential regulator of VSMC apoptosis and proliferation. The downregulation of PDCD4 expression in diseased vascular walls may be responsible for the imbalance of VSMC proliferation and apoptosis. The results indicate that PDCD4 may be a new therapeutic target in proliferative vascular diseases.


2013 ◽  
Vol 99 (3) ◽  
pp. 525-534 ◽  
Author(s):  
Keith Allen-Redpath ◽  
Ou Ou ◽  
John H. Beattie ◽  
In-Sook Kwun ◽  
Jorg Feldmann ◽  
...  

1980 ◽  
pp. 567-569
Author(s):  
Michael B. Stemerman ◽  
Itzhak D. Goldberg ◽  
Ruth T. Gardner ◽  
Robert L. Fuhro

1979 ◽  
Author(s):  
R.L. Kinlough-Rathbone ◽  
H.M. Groves ◽  
S. Maric ◽  
M.A. Packham ◽  
J.F. Mustard

Following a single balloon catheter injury to a rabbit aorta (INJ 1) a monolayer of platelets covers the subendothelium within 10 min, the surface becomes relatively non-reactive to further platelet accumulation and platelet survival is not altered. We have now studied whether a second similar injury (INJ 2) of the non-reactive, smooth muscle cell-rich neointima 7 days after INJ 1 makes the surface of the neointima reactive to platelets or alters platelet survival. 51Cr-platelet adherence to the neointima of aortae subjected to INJ 2 in vitro 7 days after an initial in vivo injury was not significantly different from the adherence following a single in vitro injury (16,600 ± 3100 platelets/mm2 and 27,600 ± 4000 respectively, ρ > 0.2). In vivo adherence of 51Cr-platelets to the surface of rabbit aortae was similar following INJ 1 (0.084 ± 0.009% of the circulate, platelets) and INJ 2 (0.130 ± 0.03%, p > 0.2). Platelet survival after injury to the neointima was not significantly different in animals with an undamaged aortic endothelium (74.6 ± 5.9 hr and 80.2 ± 4.3 hr respectively, ρ > 0.5). Thus, a second injury involving the smooth’ muscle cell-rich neointima that forms after removal of the endothelium with a balloon catheter does not cause more platelets to accumulate than the initial injury, nor shorten platelet survival.


2005 ◽  
Vol 79 (16) ◽  
pp. 10788-10795 ◽  
Author(s):  
Ryan M. Melnychuk ◽  
Patsy Smith ◽  
Craig N. Kreklywich ◽  
Franziska Ruchti ◽  
Jennifer Vomaske ◽  
...  

ABSTRACT Mouse cytomegalovirus (MCMV) encodes two potential seven-transmembrane-spanning proteins with homologies to cellular chemokine receptors, M33 and M78. While these virus-encoded chemokine receptors are necessary for the in vivo pathogenesis of MCMV, the function of these proteins is unknown. Since vascular smooth muscle cell (SMC) migration is of critical importance for the development of atherosclerosis and other vascular diseases, the ability of M33 to promote SMC motility was assessed. Similar to human CMV, MCMV induced the migration of mouse aortic SMCs but not mouse fibroblasts. To demonstrate whether M33 was required for MCMV-induced SMC migration, we employed interfering-RNA technology to specifically knock down M33 expression in the context of viral infection. The knockdown of M33 resulted in the specific reduction of M33 protein expression and ablation of MCMV-mediated SMC migration but failed to reduce viral growth in cultured cells. Adenovirus vector expression of M33 was sufficient to promote SMC migration, which was enhanced in the presence of recombinant mouse RANTES (mRANTES). In addition, M33 promoted the activation of Rac1 and extracellular signal-related kinase 1/2 upon stimulation with mRANTES. These findings demonstrate that mRANTES is a ligand for this chemokine receptor and that the activation of M33 occurs in a ligand-dependent manner. Thus, M33 is a functional homologue of US28 that is required for MCMV-induced vascular SMC migration.


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