Nikolaos Stergiopoulos

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Central aortic pressure gives better insight into ventriculo-arterial coupling and better prognosis of cardiovascular complications than peripheral pressures. Therefore transfer functions (TF), reconstructing aortic pressure from peripheral pressures, are ...

Alterations of wall shear stress can predispose the endothelium to the development of atherosclerotic plaques. Ample evidence indicates that arginase expression and/or activity correlates with several risk factors for cardiovascular disease including ather ...

A new separation technique has been developed to determine the forward and backward running arterial pressure wave components. It takes into account friction as well as nonlinear effects due to convective acceleration and to the pressure dependence of the arterial compliance. The new method is a combination of two methods treating friction and nonlinearities separately. The method requires the measurements of pressure and flow at one location as well as the knowledge of the area-pressure relationship. The v

This report demonstrates the feasibility of surface-initiated atom transfer radical polymerization to prepare thin polymer layers ("brushes") that can be functionalized with short peptide ligands and which may be of use as coatings to promote endothelializ ...

Previous theoretical models of arterial remodeling in response to changes in blood flow were based on the assumption that material properties of the arterial wall remain unchanged during the remodeling process. According to experimental findings, however, ...

We derived and tested a new, simple, and accurate method to estimate the compliance of the entire arterial tree and parts thereof. The method requires the measurements of pressure and flow and is based on fitting the pulse pressure (systolic minus diastolic pressure) predicted by the two-element windkessel model to the measured pulse pressure. We show that the two-element windkessel model accurately describes the modulus of the input impedance at low harmonics (0-4th) of the heart rate so that the gross fea

This study aimed to model phenomenologically the dynamics of arterial wall remodeling under hypertensive conditions. Sustained hypertension was simulated by a step increase in blood pressure. The arterial wall was considered to be a thick-walled tube made of nonlinear elastic incompressible material. Remodeling rate equations were postulated for the evolution of the geometric dimensions of the hypertensive artery at the zero-stress state, as well as for one of the material constants in the constitutive equa

The beating heart creates blood pressure and flow pulsations that propagate as waves through the arterial tree that are reflected at transitions in arterial geometry and elasticity. Waves carry information about the matter in which they propagate. Therefore, modeling of arterial wave propagation extends our knowledge about the functioning of the cardiovascular system and provides a means to diagnose disorders and predict the outcome of medical interventions. In this review we focus on the physical and mathe

During aging, systolic blood pressure continuously increases over time, whereas diastolic pressure first increases and then slightly decreases after middle age. These pressure changes are usually explained by changes of the arterial system alone (increase ...

Cannabinoids are considered as key mediators in the pathophysiology of inflammatory diseases, including atherosclerosis. In particular, they have been shown to reduce the ischemic injury after acute cardiovascular events, such as acute myocardial infarction and ischemic stroke. These protective and anti-inflammatory properties on peripheral tissues and circulating inflammatory have been demonstrated to involve their binding with both selective cannabinoid type 1 (CB1) and type 2 (CB2) transmembrane receptor

IntroductionAngiotensin-converting enzyme 2 (ACE2) is a key enzyme of the renin angiotensin system, which breaks down angiotensin II and forms angiotensin-(1-7). In erectile tissues, it has been documented that angiotensin II contributes to the development ...

Martin BA, Reymond P, Novy J, Baledent O, Stergiopulos N. A coupled hydrodynamic model of the cardiovascular and cerebrospinal fluid system. Am J Physiol Heart Circ Physiol 302: H1492-H1509, 2012. First published January 20, 2012; doi: 10.1152/ajpheart.006 ...

Hemodynamic forces play a critical role in atherogenesis, as evidenced by the focal pattern of development of atherosclerotic lesions. Whereas disturbed flow in the branches and curved regions of large arteries is proatherogenic, laminar flow in the straig ...

Ventricular-arterial coupling is a major determinant of cardiovascular performance, however, there are still inherent difficulties in distinguishing ventricular from vascular effects on arterial pulse phenotypes. In the present study, we employed an extens ...

A nonlinear method has been developed to separate arterial pressure and flow waves into their forward and backward running components. It takes into account nonlinearities arising from the area-pressure relationship as well as convective acceleration. The method is based on the treatment of the Riemann invariants and requires measurements of pressure, flow and diameter at one arterial location. The method has been successfully tested by means of a simulation experiment in which the forward and backward wave

Isobaric compliance and distensibility of the radial artery were recently reported to be normal or slightly increased in untreated hypertensive patients. However, these findings provide no information on the intrinsic mechanical properties of the wall material. To address this question, we determined intima-media wall thickness, wall-to-lumen ratio, and incremental elastic modulus in the radial artery of 25 untreated hypertensive patients with blood pressure of 150 +/- 14/103 +/- 6 mm Hg (mean +/- SD) and 2

Background: Neurogenic erectile dysfunction (ED) following radical prostatectomy (RP) is a frequent complication often leading to erectile tissue remodeling and permanent ED. Low-intensity electrostimulation (LIES) has been shown to enhance peripheral nerv ...

Recent advance in imaging modalities used frequently in clinical routine can provide description of the geometrical and hemodynamical properties of the arterial tree in great detail. The combination of such information with models of blood flow of the arte ...

Background and aims: Lysophosphatidylcholine (LPC) - a main component of oxidized LDL -is involved in endothelial dysfunction that precedes atherosclerosis, with an increased superoxide anions and a reduced NO production via endothelial NO synthase (eNOS) ...

Systems and methods are provided for treating diseases that produce elevated pressure, e.g., intraocular pressure or cerebrospinal fluid pressure, such as glaucoma or hydrocephalus, wherein the device includes a housing shell, an elastic membrane, and a local constriction that reduces the area of the fluidic passageway through the housing shell and increases fluidic resistance of the flow of fluid through the passageway. At normal IOP levels, the elastic membrane engages the local constriction to prevent or

Nikolaos Stergiopoulos

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Individualization of transfer function in estimation of central aortic pressure from the peripheral pulse is not required in patients at rest

Regulation of arginase pathway in response to wall shear stress

Separation of arterial pressure waves into their forward and backward running components

RGD-Functionalized polymer brushes as substrates for the integrin specific adhesion of human umbilical vein endothelial cells

Arterial remodeling in response to increased blood flow using a constituent-based model

Simple and accurate way for estimating total and segmental arterial compliance: the pulse pressure method

A model for geometric and mechanical adaptation of arteries to sustained hypertension

Pulse Wave Propagation in the Arterial Tree

Contribution of the Arterial System and the Heart to Blood Pressure during Normal Aging - A Simulation Study

Update on the Role of Cannabinoid Receptors after Ischemic Stroke

Diminazene Protects Corpus Cavernosum Against Hypercholesterolemia-Induced Injury

A coupled hydrodynamic model of the cardiovascular and cerebrospinal fluid system

Shear stress and cyclic circumferential stretch, but not pressure, alter connexin43 expression in endothelial cells

The effect of left ventricular contractility on arterial hemodynamics: A model-based investigation

Forward and backward waves in the arterial system: nonlinear separation using Riemann invariants

Contributions of vascular tone and structure to elastic properties of a medium-sized artery

Low-Intensity Electrostimulation Enhances Neuroregeneration and Improves Erectile Function in a Rat Model of Cavernous Nerve Injury

Generic and patient-specific models of the arterial tree

Role of ERK1/2 activation and nNOS uncoupling on endothelial dysfunction induced by lysophosphatidylcholine

Systems and methods for treating excess pressure having an elastic membrane in fluid contact with bodily fluid