It has been found that the incidence of cardiovascular disease in patients with lower limb amputation is significantly higher than that in normal individuals, but the relationship between lower limb amputation and the episodes of cardiovascular disease has not been studied from the perspective of hemodynamics. In this paper, numerical simulation was used to study the effects of amputation on aortic hemodynamics by changing peripheral impedance and capacitance. The final results showed that after amputation, the aortic blood pressure increased, the time averaged wall shear stress of the infrarenal abdominal aorta decreased and the oscillatory shear index of the left and right sides was asymmetrically distributed, while the time averaged wall shear stress of the iliac artery decreased and the oscillatory shear index increased. The changes above were more significant with the increase of amputation level, which will result in a higher incidence of atherosclerosis and abdominal aortic aneurysm. These findings preliminarily revealed the influence of lower limb amputation on the occurrence of cardiovascular diseases, and provided theoretical guidance for the design of rehabilitation training and the optimization of cardiovascular diseases treatment.
Amputation ; Aorta, Abdominal/surgery* ; Aortic Aneurysm, Abdominal/surgery* ; Blood Flow Velocity/physiology* ; Hemodynamics/physiology* ; Humans ; Lower Extremity ; Models, Cardiovascular ; Stress, Mechanical

This study aims to explore the effect of aortic sinus diameter on aortic valve opening and closing performance in the case of no obvious disease of aortic valve and annulus and continuous dilation of aortic root. A total of 25 three-dimensional aortic root models with different aortic sinus and root diameters were constructed according to the size of clinical surgical guidance. The valve sinus diameter S is set to 32, 36, 40, 44 and 48 mm, respectively, and the aortic root diameter is set to 26, 27, 28, 29 and 30 mm, respectively. Through the structural mechanics calculation with the finite element software, the maximum stress, valve orifice area, contact force and other parameters of the model are analyzed to evaluate the valve opening and closing performance under the dilated state. The study found that aortic valve stenosis occurs when the = 32 mm, = 26, 27 mm and = 36 mm, = 26 mm. Aortic regurgitation occurs when the = 32, 36 and 40 mm, = 30 mm and = 44, 48 mm, = 29, 30 mm. The other 15 models had normal valve movement. The results showed that the size of the aortic sinus affected the opening and closing performance of the aortic valve. The smaller sinus diameter adapted with the larger root diameter and the larger sinus diameter adapted with the smaller root diameter. When the sinus diameter is 40 mm, the mechanical performance of the valve are good and it can well adapt with the relatively large range of aortic root dilation.
Aorta ; anatomy & histology ; Aortic Valve ; physiology ; Aortic Valve Insufficiency ; physiopathology ; Aortic Valve Stenosis ; physiopathology ; Humans

The mechanical properties of the aorta tissue is not only important for maintaining the cardiovascular health, but also is closely related to the development of cardiovascular diseases. There are obvious differences between the ventral and dorsal tissues of the descending aorta. However, the cause of the difference is still unclear. In this study, a biaxial tensile approach was used to determine the parameters of porcine descending aorta by analyzing the stress-strain curves. The strain energy functions Gasser-Ogden-Holzapfel was adopted to characterize the orthotropic parameters of mechanical properties. Elastic Van Gieson (EVG) and Sirius red stain were used to observe the microarchitecture of elastic and collagen fibers, respectively. Our results showed that the tissue of descending aorta had more orthotropic and higher elastic modulus in the dorsal region compared to the ventral region in the circumferential direction. No significant difference was found in hyperelastic constitutive parameters between the dorsal and ventral regions, but the angle of collagen fiber was smaller than 0.785 rad (45°) in both dorsal and ventral regions. The arrangement of fiber was inclined to be circumferential. EVG and Sirius red stain showed that in outer-middle membrane of the descending aorta, the density of elastic fibrous layer of the ventral region was higher than that of the dorsal region; the amount of collagen fibers in dorsal region was more than that of the ventral region. The results suggested that the difference of mechanical properties between the dorsal and ventral tissues in the descending aorta was related to the microstructure of the outer membrane of the aorta. In the relatively small strain range, the difference in mechanical properties between the ventral and dorsal tissues of the descending aorta can be ignored; when the strain is higher, it needs to be treated differently. The results of this study provide data for the etiology of arterial disease (such as arterial dissection) and the design of artificial blood vessel.
Animals ; Aorta, Thoracic ; physiology ; Biomechanical Phenomena ; Collagen ; Elastic Modulus ; Stress, Mechanical ; Swine

PURPOSE: Children born with single ventricle physiology demonstrate poor growth rate and suffer from malnutrition, which lead to increased morbidity and mortality in this population. We assume that an anabolic steroid, oxandrolone, will promote growth in these infants by improving myocardial energy utilization. The purpose of this paper is to study the efficacy of oxandrolone on myocardial energy consumption in these infants. MATERIALS AND METHODS: We modeled single ventricle physiology in a lamb by prenatally shunting the aorta to the pulmonary artery and then postnatally, we monitored cardiac energy utilization by quantitatively measuring the first order reaction rate constant, kf of the creatine-kinase reaction in the heart using magnetization transfer 31P magnetic resonance spectroscopy, home built 1H/31P transmit/receive double tuned coil, and transmit/receive switch. We also performed cine MRI to study the structure and dynamic function of the myocardium and the left ventricular chamber. The spectroscopy data were processed using home-developed python software, while cine data were analyzed using Argus software. RESULTS: We quantitatively measured both the first order reaction rate constant and ejection fraction in the control, shunted, and the oxandrolone-treated lambs. Both kf and ejection fraction were found to be more significantly reduced in the shunted lambs compared to the control lambs, and they are increased in oxandrolone-treated lambs. CONCLUSION: Some improvement was observed in both the first order reaction rate constant and ejection fraction for the lamb treated with oxandrolone in our preliminary study.
Aorta ; Boidae ; Child ; Evaluation Studies as Topic ; Heart ; Humans ; Infant ; Magnetic Resonance Imaging, Cine ; Magnetic Resonance Spectroscopy ; Malnutrition ; Mortality ; Myocardium ; Oxandrolone ; Physiology ; Pulmonary Artery ; Spectrum Analysis

PURPOSE: Diabetes mellitus (DM) is the most common cause of end-stage renal disease (ESRD) and an important risk factor for cardiovascular (CV) disease. We investigated the impact of DM on subclinical CV damage by comprehensive screening protocol in ESRD patients. MATERIALS AND METHODS: Echocardiography, coronary computed tomography angiogram, 24-h ambulatory blood pressure monitoring, and central blood pressure with pulse wave velocity (PWV) were performed in 91 ESRD patients from the Cardiovascular and Metabolic disease Etiology Research Center-HIgh risk cohort. RESULTS: The DM group (n=38) had higher systolic blood pressure than the non-DM group (n=53), however, other clinical CV risk factors were not different between two groups. Central aortic systolic pressure (148.7±29.8 mm Hg vs. 133.7±27.0 mm Hg, p= 0.014), PWV (12.1±2.7 m/s vs. 9.4±2.1 m/s, p<0.001), and early mitral inflow to early mitral annulus velocity (16.7±6.4 vs. 13.7±5.9, p=0.026) were higher in the DM group. Although the prevalence of coronary artery disease (CAD) was not different between the DM and the non-DM group (95% vs. 84.4%, p=0.471), the severity of CAD was higher in the DM group (p=0.01). In multivariate regression analysis, DM was an independent determinant for central systolic pressure (p=0.011), PWV (p<0.001) and the prevalence of CAD (p=0.046). CONCLUSION: Diabetic ESRD patients have higher central systolic pressure and more advanced arteriosclerosis than the non-DM control group. These findings suggest that screening for subclinical CV damage may be helpful for diabetic ESRD patients.
Aged ; Aorta ; Biomarkers ; Blood Pressure/physiology ; Blood Pressure Monitoring, Ambulatory ; Coronary Artery Disease/diagnostic imaging/*physiopathology ; Diabetes Mellitus/*physiopathology ; Diabetic Nephropathies/physiopathology ; Echocardiography ; Female ; Humans ; Kidney Failure, Chronic/*physiopathology ; Male ; Middle Aged ; Pulse Wave Analysis ; Regression Analysis ; Risk Factors ; Systole/physiology

PURPOSE: Oxidative stress during CO2 pneumoperitoneum is reported to be associated with decreased bioactivity of nitric oxide (NO). However, the changes in endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and arginase during CO2 pneumoperitoneum have not been elucidated. MATERIALS AND METHODS: Thirty male Sprague-Dawley rats were randomized into three groups. After anesthesia induction, the abdominal cavities of the rats of groups intra-abdominal pressure (IAP)-10 and IAP-20 were insufflated with CO2 at pressures of 10 mm Hg and 20 mm Hg, respectively, for 2 hours. The rats of group IAP-0 were not insufflated. After deflation, plasma NO was measured, while protein expression levels and activity of eNOS, iNOS, arginase (Arg) I, and Arg II were analyzed with aorta and lung tissue samples. RESULTS: Plasma nitrite concentration and eNOS expression were significantly suppressed in groups IAP-10 and IAP-20 compared to IAP-0. While expression of iNOS and Arg I were comparable between the three groups, Arg II expression was significantly greater in group IAP-20 than in group IAP-0. Activity of eNOS was significantly lower in groups IAP-10 and IAP-20 than in group IAP-0, while iNOS activity was significantly greater in group IAP-20 than in groups IAP-0 and IAP-10. Arginase activity was significantly greater in group IAP-20 than in groups IAP-0 and IAP-10. CONCLUSION: The activity of eNOS decreases during CO2 pneumoperitoneum, while iNOS activity is significantly increased, a change that contributes to increased oxidative stress and inflammation. Moreover, arginase expression and activity is increased during CO2 pneumoperitoneum, which seems to act inversely to the NO system.
Animals ; Aorta/*physiology ; Arginase/*antagonists & inhibitors ; Enzyme Inhibitors/administration & dosage/pharmacology ; Inflammation/etiology/*prevention & control ; Injections, Subcutaneous ; Lung Injury/etiology/prevention & control ; Male ; Nitric Oxide/metabolism ; Nitric Oxide Synthase Type II/*metabolism ; Nitric Oxide Synthase Type III/*metabolism ; Oxidative Stress/*drug effects ; Pneumoperitoneum/*complications/drug therapy ; Rats ; Rats, Sprague-Dawley

This study evaluated the myocardial strain and aortic elasticity in patients with bicuspid aortic valve (BAV) and then investigated the relation between them. Thirty-nine patients (30 males; mean age 44±19 years; range 6 to 75 years) with BAV were recruited as BAV group, and 29 age- and sex-matched healthy controls (21 males; mean age 42±11 years; range 20 to 71 years) served as control group. Aortic strain, distensibility and stiffness index were derived using M-mode echocardiography. Left ventricular global myocardial strain was acquired with speckle-tracking echocardiography. Correlation between aortic elasticity and myocardial strain was also analyzed. The results showed that aortic stiffness was higher (17.5±14.0 vs. 5.3±2.7, P<0.001), and aortic strain (4.9±4.7 vs. 11.0±4.1, P<0.001) and distensibility (1.8±2.1 vs. 3.7±1.6, P<0.001) were lower significantly in BAV group than in control group. Global circumferential strain (-19.1±4.2 vs.-22.5±3.7, P<0.001), radial stain (29.8±14.9 vs. 38.0±8.8, P<0.001) and longitudinal stain (-18.4±3.4 vs.-20.8±3.5, P<0.001) were significantly lower in BAV group than in control group. There was weak association between aortic elasticity and myocardial strain. These findings indicated BAV patients manifest reduced myocardial strain which had weak relationship with aortic elastic lesion.
Adolescent ; Adult ; Aged ; Aorta ; pathology ; Aortic Valve ; abnormalities ; pathology ; Child ; Echocardiography ; Elasticity ; Female ; Heart Valve Diseases ; pathology ; Humans ; Male ; Middle Aged ; Myocardium ; pathology ; Sprains and Strains ; pathology ; Vascular Stiffness ; physiology

The present study attempted to test a novel hypothesis that Ca(2+) sparks play an important role in arterial relaxation induced by tacrolimus. Recorded with confocal laser scanning microscopy, tacrolimus (10 µmol/L) increased the frequency of Ca(2+) sparks, which could be reversed by ryanodine (10 µmol/L). Electrophysiological experiments revealed that tacrolimus (10 µmol/L) increased the large-conductance Ca(2+)-activated K(+) currents (BKCa) in rat aortic vascular smooth muscle cells (AVSMCs), which could be blocked by ryanodine (10 µmol/L). Furthermore, tacrolimus (10 and 50 µmol/L) reduced the contractile force induced by norepinephrine (NE) or KCl in aortic vascular smooth muscle in a concentration-dependent manner, which could be also significantly attenuated by iberiotoxin (100 nmol/L) and ryanodine (10 µmol/L) respectively. In conclusion, tacrolimus could indirectly activate BKCa currents by increasing Ca(2+) sparks released from ryanodine receptors, which inhibited the NE- or KCl-induced contraction in rat aorta.
Animals ; Aorta ; cytology ; metabolism ; physiology ; Calcium Signaling ; Cells, Cultured ; Large-Conductance Calcium-Activated Potassium Channels ; metabolism ; Male ; Muscle, Smooth, Vascular ; drug effects ; metabolism ; physiology ; Myocytes, Smooth Muscle ; drug effects ; metabolism ; Norepinephrine ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Ryanodine ; pharmacology ; Tacrolimus ; pharmacology ; Vasoconstriction

To investigate the changes of aortic stiffness and its influencing factors in patients with chronic kidney diseases (CKD).Eightyfour patients with CKD from Department of Nephrology, Zhejiang Provincial People's Hospital were divided into the dialysis group (CKD stage 5,=48) and non-dialysis group (CKD stage 3-5,=36). Clinical data, biochemical parameters and echocardiography findings were collected. SphygmoCor pulse wave analysis system was used to obtain pulse wave analysis (PWA) parameters including central aortic systolic blood pressure (CSP), central pulse pressure (CPP), augmented pressure (AP), augmentation index (AIX), and heart rate 75-adjusted augmentation index (HR75AIX). The influencing factors of aortic stiffness were analyzed by spearman correlation analysis and multiple regression analysis.CSP, CPP, AP, AIX and HR75AIX in dialysis patients had no significant differences compared with those in non-dialysis group (all>0.05). Spearman correlation analysis showed that CSP was positively correlated with systolic blood pressure, diastolic blood pressure, cholesterol, low-density lipoprotein cholesterol, left atrial diameter (LA),left ventricular systolic diameter (LVDs), left ventricular diastolic diameter (LVDd), and negatively correlated with calcium and hemoglobin levels. CPP was positively correlated with systolic blood pressure, age, LA, LVDd, and negatively correlated with diastolic blood pressure and hemoglobin levels. AP was positively correlated with systolic blood pressure, age, LA, LVDd, and negatively correlated with hemoglobin levels. AIX was positively correlated with systolic blood pressure, age, sodium, and negatively correlated with phosphorus levels. HR75AIX was positively correlated with systolic blood pressure, sodium, cholesterol, and negatively correlated with hemoglobin and albumin levels. Multiple regression analysis showed that higher systolic blood pressure was the independent risk factor for CSP (β=0.944,<0.01); lower diastolic blood pressure (β=0.939,<0.01) and higher systolic blood pressure (β=-1.010,<0.01) were the independent risk factors for CPP; older age (β=0.237,<0.01) and higher systolic blood pressure (β=0.200,<0.01) were the independent risk factors for AP; higher systolic blood pressure (β=0.163 and 0.115,<0.05 and<0.01) and higher sodium (β=0.646 and 0.625, all<0.05) were independent risk factors for both AIX and HR75AIX.No significant correlation is observed between aortic stiffness and CKD of different stages. Control blood pressure and restrict sodium intake may be effective means of delaying arterial stiffness in patients with CKD.
Age Factors ; Aorta ; pathology ; Blood Pressure ; physiology ; Cholesterol ; Dialysis ; Female ; Heart Atria ; Humans ; Male ; Middle Aged ; Regression Analysis ; Renal Insufficiency, Chronic ; complications ; Risk Factors ; Sodium, Dietary ; adverse effects ; Vascular Stiffness ; physiology

OBJECTIVETo observe the effect of β₃adrenoceptors (β₃-AR) activation on rat thoracic aorta smooth muscle contractility and the possible related mechanism.

METHODSThe endothelium removed thoracic aorta was pre-contracted with 30 mmol/L KCl physiological saline solution (PSS). Then the tension of the thoracic aorta was recorded in presence of BRL37344 (BRL) to determine the action of β₃-AR. The tension of the thoracic aorta was also recorded in the presence of Propranolol (PRA), SR59230A (SR), L-NNA, H-89 and Iberiotoxin (IBTX) respectively to reveal the underling mechanism of β₃-AR activation on rat vascular smooth muscle. Immunohistochemistry was adopted to confirm the existence and the distribution of β₃-AR in rat thoracic aorta.

RESULTSThe results showed that: (1) The thoracic aorta was relaxed by β₃-AR activation, with a relaxation percentage of (10.59 ± 0.79). (2) β₃-AR was expressed in both endothelial and smooth muscle layer in thoracic aorta sections of rats. (3) PRA did not block the effect of BRL on the thoracic aorta. The relaxation actions of BRL could be antagonized by pre-incubating the thoracic aorta with SR. (4) L-NNA (a NOS inhibitor) and H-89 (a PKA inhibitor) reversed the relaxation effect of BRL on vascular smooth muscle. (5) The effect of BRL was decreased after application of Ibriotoxin (IBTX), a large conductance calcium dependent potassium channel blocker.

CONCLUSIONThe results confirmed that activation of β₃-AR led to relaxation of thoracic aorta smooth muscle. The relaxation action of β₃-AR on smooth muscle of rat thoracic aorta was related to activation of NOS and PKA signaling pathway. Large conductance Ca²⁺-K⁺ channels were involved in the relaxation action of β₃-AR activation on rat thoracic aorta smooth muscle.

Animals ; Aorta, Thoracic ; physiology ; In Vitro Techniques ; Isoquinolines ; Large-Conductance Calcium-Activated Potassium Channels ; physiology ; Muscle Contraction ; Muscle Relaxation ; Muscle, Smooth, Vascular ; physiology ; Nitroarginine ; Peptides ; Propanolamines ; Propranolol ; Rats ; Receptors, Adrenergic, beta-3 ; physiology ; Signal Transduction ; Sulfonamides