Jean-Jacques Meister

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Recent experimental studies have shown significant alterations of the vascular smooth muscle (VSM) tone when an artery is subjected to an elevation in pressure. Therefore, the VSM participates in the adaptation process not only by means of its synthetic activity (fibronectins and collagen) or proliferative activity (hypertrophy and hyperplasia) but also by adjusting its contractile properties and its tone level. In previous theoretical models describing the time evolution of the arterial wall adaptation in

Protrusion, the first step of cell migration, is driven by actin polymerization coupled to adhesion at the cell's leading edge. Polymerization and adhesive forces have been estimated, but the net protrusion force has not been measured accurately. We arrest ...

Vascular smooth muscle cells exhibit intercellular Ca2+ waves in response to local mechanical or KCl stimulation. Recently, a new type of intercellular Ca2+ wave was observed in vitro in a linear arrangement of smooth muscle cells. The intercellular wave w ...

A three-dimensional finite element model of the carotid artery bifurcation was constructed in order to determine the stress field and assess the modification of the stress field when residual strain is taken into account. Residual strain in the carotid bifurcation was characterized by experimental observations. According to these observations, a geometrical model of the carotid artery was constructed to exhibit a state free of strain. Appropriate boundary conditions were applied to yield the correct geometr

The biophysical properties of the interaction between fibronectin and its membrane receptor were inferred from adhesion tests on living cells. Individual fibroblasts were maintained on fibronectin-coated glass for short time periods (1-16 s) using optical tweezers. After contact, the trap was removed quickly, leading to either adhesion or detachment of the fibroblast. Through a stochastic analysis of bond kinetics, we derived equations of adhesion probability versus time, which fit the experimental data wel

Most previous studies of arterial wall elasticity and rheology have assumed that the properties of the wall are uniform across the thickness of the media and, therefore, that the relationship between stress and strain may be described by a constitutive equation based on a single strain energy function. The few studies where this assumption has been questioned, focussed on differences between the adventitia and the media rather than on differences within the media itself. Here, we report in vitro elasticity

A finite element model of the human carotid bifurcation was developed to investigate the possibility that pressure-induced arterial wall stresses lead to the formation of atherosclerosis. The effect of material non-homogeneity was investigated by measuring the distribution of collagen and elastin in cadaver specimens and applying different material constants where appropriate. Both the homogeneous and non-homogeneous models included the residual stresses. The histology results revealed that the outer wall o

Vasomotion consists of cyclic arterial diameter variations induced by synchronous contractions and relaxations of smooth muscle cells. However, the arteries do not contract simultaneously on macroscopic distances, and a propagation of the contraction can b ...

METHODOLOGY: A new non-invasive ultrasonic device was developed to characterize the biomechanical properties of medium and large peripheral arteries. Simultaneous recordings of internal diameter and blood pressure over the whole cardiac cycle are used to establish compliance-pressure curves. Since blood pressure, which is an inherent co-determinant of arterial compliance, is taken into account, the comparison of arteries from patients with markedly different blood pressures has become possible. In a first s

We studied the changes in vascular smooth muscle (VSM) cell tone during the adaptation of rat common carotids to induced hypertension. Hypertension was induced in 8 week old male Wistar rats by total ligation of the aorta between the two kidneys. Mean blood pressure increased abruptly from 92 +/- 2mm Hg (mean +/- SE) to 145 +/- 4 mm Hg and remained constant thereafter. Rats were sacrificed 2, 4, 8, and 56 days after surgery and the left common carotid artery was excised for analysis. Pressure-diameter curve

Arterial vasomotion and its relation to intraluminal pressure were investigated in vitro in isolated rat arteries. Femoral arteries (mean diameter = 768.2 +/- 25 microns, n = 5) and mesenteric arteries (mean diameter = 393.4 +/- 32 microns, n = 5) were used in this study. Arterial segments were excised, mounted on microcannulas and perfused with Tyrode's solution at a constant flow (100 microliters/min). After equilibration, intraluminal pressure was stepwise changed from 0 to 120 mm Hg. The changes in the

The biomechanical adaptation of the arterial wall to hypertension has been studied extensively in recent years; however, the exact biomechanical contribution of vascular smooth muscle cells (VSMCs) during the adaptation process in conduit vessels is not known. We induced hypertension in 8 wk old Wistar rats by total ligation of the aorta between the two kidneys. Mean blood pressure increased from 92 +/- 2 (mean +/- SE) mm Hg to approximately 150 mmHg. Rats were sacrificed 2, 4, and 8 d after surgery and the

Cultured vascular endothelial cells undergo significant morphological changes when subjected to sustained fluid shear stress. The cells elongate and align in the direction of applied flow. Accompanying this shape change is a reorganization at the intracellular level. The cytoskeletal actin filaments reorient in the direction of the cells' long axis. How this external stimulus is transmitted to the endothelial cytoskeleton still remains unclear. In this article, we present a theoretical model accounting for

We investigated the patterns of vasomotion in various conduit arteries of the human arm. The internal diameter of the brachial, radial, ulnar, and digital artery was measured noninvasively in 17 healthy volunteers (aged 24-40 yr), using a high-precision ultrasonic echotracking device. Under resting conditions, the radial, ulnar, and digital internal diameter exhibited spontaneous oscillations (vasomotion) with a relative amplitude ranging from 1 to 5% of the mean diameter and a fundamental frequency ranging

Chondrocytes depend upon solute transport within the avascular extracellular matrix of adult articular cartilage for many of their biological activities. Alterations to bioactive solute transport may, therefore, represent a mechanism by which cartilage compression is transduced into cellular metabolic responses. We investigated the effects of cartilage static compression on diffusivity and partitioning of a range of model solutes including dextrans of molecular weights 3 and 40 kDa, and tetramethylrhodamine

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

The cell nucleus plays a central role in the response of the endothelium to mechanical forces, possibly by deforming during cellular adaptation. The goal of this work was to precisely quantify the mechanical properties of the nucleus. Individual endothelial cells were subjected to compression between glass microplates. This technique allows measurement of the uniaxial force applied to the cell and the resulting deformation. Measurements were made on round and spread cells to rule out the influence of cell m

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

To characterize the dynamics of cell-substrate adhesive rupture, we used a novel micromanipulation technique, in which individual fibroblasts seized on a rigid microplate were placed into contact with a fibronectin-coated flexible microplate, then pulled away. The fibronectin density (0-3000 molecules/microm2) and the pulling rate (1-10 microm/s) were controlled. The extent of the contact zone decreased to zero at a time threshold corresponding to adhesive rupture. The uniaxial force at the interface, compu

Jean-Jacques Meister

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Model of geometrical and smooth muscle tone adaptation of carotid artery subject to step change in pressure

Weak force stalls protrusion at the leading edge of the lamellipodium

Intercellular ultrafast Ca2+ wave in vascular smooth muscle cells: numerical and experimental study

Residual strain effects on the stress field in a thick wall finite element model of the human carotid bifurcation

Short-term binding of fibroblasts to fibronectin: optical tweezers experiments and probabilistic analysis

Assessing the homogeneity of the elastic properties and composition of the pig aortic media

Wall stresses in the carotid bifurcation: Effects of wall non-homogeneity and correlation with intimal thickness

Intercellular calcium waves are associated with the propagation of vasomotion along arterial strips

Non-invasive determination of arterial diameter and distensibility by echo-tracking techniques in hypertension

Adaptation of conduit artery vascular smooth muscle tone to induced hypertension

Intraluminal pressure modulates the magnitude and the frequency of induced vasomotion in rat arteries

Short-Term biomechanical adaptation of the rat carotid to acute hypertension: contribution of smooth muscle

Model for the alignment of actin filaments in endothelial cells subjected to fluid shear stress

Simultaneous ipsilateral and contralateral measurements of vasomotion in conduit arteries of human upper limbs

Static compression of articular cartilage can reduce solute diffusivity and partitioning: implications for the chondrocyte biological response

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

Contribution of the nucleus to the mechanical properties of endothelial cells

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

Dynamics of adhesive rupture between fibroblasts and fibronectin: microplate manipulations and deterministic model