Passive Wall Stiffness Research Articles

Acetylsalicylic Acid Reduces Passive Aortic Wall Stiffness and Cardiovascular Remodelling in a Mouse Model of Advanced Atherosclerosis.

Acetylsalicylic acid (ASA) is widely used in secondary prevention of cardiovascular (CV) disease, mainly because of its antithrombotic effects. Here, we investigated whether ASA can prevent the progression of vessel wall remodelling, atherosclerosis, and CV complications in apolipoprotein E deficient (ApoE−/−) mice, a model of stable atherosclerosis, and in ApoE−/− mice with a mutation in the fibrillin-1 gene (Fbn1C1039G+/−), which is a model of elastic fibre fragmentation, accompanied by exacerbated unstable atherosclerosis. Female ApoE−/− and ApoE−/−Fbn1C1039G+/− mice were fed a Western diet (WD). At 10 weeks of WD, the mice were randomly divided into four groups, receiving either ASA 5 mg/kg/day in the drinking water (ApoE−/− (n = 14), ApoE−/−Fbn1C1039G+/− (n = 19)) or plain drinking water (ApoE−/− (n = 15), ApoE−/−Fbn1C1039G+/− (n = 21)) for 15 weeks. ApoE−/−Fbn1C1039G+/− mice showed an increased neutrophil–lymphocyte ratio (NLR) compared to ApoE−/− mice, and this effect was normalised by ASA. In the proximal ascending aorta wall, ASA-treated ApoE−/−Fbn1C1039G+/− mice showed less p-SMAD2/3 positive nuclei, a lower collagen percentage and an increased elastin/collagen ratio, consistent with the values measured in ApoE−/− mice. ASA did not affect plaque progression, incidence of myocardial infarction and survival of ApoE−/−Fbn1C1039G+/− mice, but systolic blood pressure, cardiac fibrosis and hypertrophy were reduced. In conclusion, ASA normalises the NLR, passive wall stiffness and cardiac remodelling in ApoE−/−Fbn1C1039G+/− mice to levels observed in ApoE−/− mice, indicating additional therapeutic benefits of ASA beyond its classical use.

Uteroplacental Insufficiency and Lactational Environment Separately Influence Arterial Stiffness and Vascular Function in Adult Male Rats

Early life environmental influences can have lifelong consequences for health, including the risk of cardiovascular disease. Uteroplacental insufficiency causes fetal undernutrition and impairs fetal growth. Previously we have shown that uteroplacental insufficiency is associated with impaired maternal mammary development, compromising postnatal growth leading to hypertension in male rat offspring. In this study we investigated the roles of prenatal and postnatal nutritional environments on endothelial and smooth muscle reactivity and passive wall stiffness of resistance arteries of male rat offspring. Fetal growth restriction was induced by maternal bilateral uterine vessel ligation (restricted) on day 18 of pregnancy. Control offspring were from mothers that had sham surgery (control) and another group from mothers with their litter size reduced (reduced; litter size reduced to 5 at birth, equivalent to the restricted group). On postnatal day 1, offspring (control, restricted, and reduced) were cross-fostered onto control or restricted mothers. At 6 months, mesenteric and femoral arteries were studied using wire and pressure myography. In restricted-on-restricted rats, wall stiffness was increased, and sensitivity to phenylephrine and relaxation evoked by endothelium-derived hyperpolarizing factor and sodium nitroprusside were impaired in mesenteric arteries. In femoral arteries, relaxation to sodium nitroprusside was reduced, whereas wall stiffness was unaltered. Cross-fostering restricted offspring onto control mothers alleviated deficits in vascular stiffness and reactivity. Control or reduced offspring who suckled a restricted mother had marked vascular stiffening. In conclusion, prenatal and early postnatal environments separately influence vascular function and stiffness. Furthermore, the early postnatal lactational environment is a determinant of later cardiovascular function.

Invited editorial on "Neuromechanical interaction in human snoring and upper airway obstruction".

in this issue of the Journal, Huang and Ffowcs Williams ([3][1]) report the development of a mathematical model that couples flow mechanics of the upper airway with neurophysiological activity. The model depends on the mechanical principle that luminal collapse occurs when passive wall stiffness is

Effect of age on passive elastic stiffness of rat heart muscle

A thick-wall spherical model for the rat left ventricle was used to deduce passive wall stiffness from diastolic pressure-volume data. This was done for rats in three age classes: young (1 mo), adult (17 mo) and old (17 mo). The model was based on finite deformation elasticity theory consistent with the magnitude of observed deformation. A least-squares procedure was used to determine elastic constants in postulated nonlinear stress-stretch relations for the myocardium. It was found that at a given level of stress, wall stiffness for ventricles in the young age class was consistently greater than wall stiffness in the other two classes. In addition, the difference in wall stiffness between rats in the adult and old age classes was found to be approximately 10%.