It is well known that vascular stiffness increases with aging, and that the effects of aging on arterial stiffness are relatively protected in older women. Although most prior mechanistic work on the effects of aging on vascular regulation and stiffness has been conducted in rodent models, the extent to which these data can be extrapolated to humans is limited by the marked differences in lifespan over which changes in vascular stiffness develop. Studies of gender differences with aging are even more limited in rodents, due to the fact that the estrogen levels never decline even in very old rodents, and they do not go through menopause. It is generally agreed that non-humans primates are the best models to study gender differences with aging, since the changes in hormones and menstruation in old female (OF) monkeys parallel those in older human females. Our previous studies and preliminary data in aging monkeys have demonstrated that the stiffness of the aorta increases with aging and this aging alteration is greater in males than females, and also much greater in the abdominal aorta (AA) vs. the thoracic aorta (TA), which is only partially explained by variance in extracellular matrix (ECM). Here, we will test the novel Hypothesis that intrinsic mechanisms in the vascular smooth muscle cells (VSMCs) as well as alterations in VSMC-ECM interaction also contribute to the increased stiffness of the aorta in older males, particularly the AA, and conversely, contribute to the protection in pre-menopausal females. This Hypothesis is supported by Preliminary Data demonstrating enhanced stiffness of VSMC in culture from old male (OM) aortas and showing that the number of senescent VSMC increases in OM compared to young males (YM), particularly in AA. Specifically, we will test our Hypothesis through two approaches. In the first approach, we will determine how VSMC stiffness and senescence are affected by age and gender using atomic force microscopy (AFM) and also an artificial tissue model. In the second approach, we will determine both in vivo and in vitro how these factors may explain the regional differences in aortic stiffness between TA and AA.
The increase in vascular stiffness is a major health problem for an increasing aging population in the US. This grant is directed at examining mechanisms inherent in this process which ultimately could be approached therapeutically.
|De Lorenzo, Mariana S; Chen, Wen; Baljinnyam, Erdene et al. (2014) 'Reduced malignancy as a mechanism for longevity in mice with adenylyl cyclase type 5 disruption'. Aging Cell 13:102-10|
|Lai, Lo; Yan, Lin; Gao, Shumin et al. (2013) Type 5 adenylyl cyclase increases oxidative stress by transcriptional regulation of manganese superoxide dismutase via the SIRT1/FoxO3a pathway. Circulation 127:1692-701|
|Bravo, Claudio; Kudej, Raymond K; Yuan, Chujun et al. (2013) Metabolomic analysis of two different models of delayed preconditioning. J Mol Cell Cardiol 55:19-26|
|Sehgel, Nancy L; Zhu, Yi; Sun, Zhe et al. (2013) Increased vascular smooth muscle cell stiffness: a novel mechanism for aortic stiffness in hypertension. Am J Physiol Heart Circ Physiol 305:H1281-7|
|Zhao, Xin; Park, Jiyeon; Ho, David et al. (2012) Cardiomyocyte overexpression of the *1A-adrenergic receptor in the rat phenocopies second but not first window preconditioning. Am J Physiol Heart Circ Physiol 302:H1614-24|
|Iwatsubo, Kosaku; Bravo, Claudio; Uechi, Masami et al. (2012) Prevention of heart failure in mice by an antiviral agent that inhibits type 5 cardiac adenylyl cyclase. Am J Physiol Heart Circ Physiol 302:H2622-8|
|Gelpi, Ricardo J; Park, Misun; Gao, Shumin et al. (2011) Apoptosis in severe, compensated pressure overload predominates in nonmyocytes and is related to the hypertrophy but not function. Am J Physiol Heart Circ Physiol 300:H1062-8|
|Ho, David; Zhao, Xin; Gao, Shumin et al. (2011) Heart Rate and Electrocardiography Monitoring in Mice. Curr Protoc Mouse Biol 1:123-139|
|Zhao, Xin; Ho, David; Gao, Shumin et al. (2011) Arterial Pressure Monitoring in Mice. Curr Protoc Mouse Biol 1:105-122|
|Zhao, Xin; Ho, David; Abarzua, Patricio et al. (2011) Inhibition of smooth muscle myosin as a novel therapeutic target for hypertension. J Pharmacol Exp Ther 339:307-12|
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