Hemodynamic forces modulate simultaneously the release of growth factors and the organisation of cytoskeleton of aortic smooth muscle-cells.
Recurrent stenosis because of myointimal hyperplasia or atherosclerosis after carotid endarterectomy occurs in 5-15% of the cases. The key event is the abnormal proliferation of arterial Smooth Muscle Cells (SMC). After endarterectomy SMC are directly exposed to the blood flowing under pressure. The aim of the present study was to determine the changes in morphology, cytoskeleton organisation, and release of growth factors by SMC exposed to laminar flow. Subconfluent SMC were exposed to a level of shear stress of 6 dyne/cm2 (100 ml/min) for 24 hours under conditions of steady laminar flow. The changes in morphology and cytoskeleton organisation were analysed by light and scanning electron microscopy, and by fluorescence microscopy. Growth factors release was assessed by ELISA. After exposure to laminar flow, SMC assumed a spindle-like shape; they lost many of their protrusions and there was a clear reorganisation of the cytoskeleton and simultaneously their released a higher quantity of PDGF and bFGF. In this study, we found simultaneous changes in cytoskeleton organisation and release of growth factors in SMC exposed to flow. Cytoskeleton reorganisation might be the mechanism through which SMC respond to changes in blood flow. These findings may help to explain the genesis of myointimal hyperplasia following carotid endarterectomy.
Cucina
A
A
I Istituto di Clinica Chirugica, University of Rome La Sapienza, Rome.
Sterpetti
A V
AV
di Carlo
A
A
Randone
B
B
Aromatario
C
C
Proietti
P
P
Giustiniani
Q
Q
Cavallaro
A
A
Santoro-D'Angelo
L
L
D003599:Cytoskeleton / Q000648:ultrastructure*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D018056:Hemorheology; D006801:Humans; D008855:Microscopy, Electron, Scanning; D009131:Muscle, Smooth, Vascular / Q000378:metabolism / Q000648:ultrastructure*; D010982:Platelet-Derived Growth Factor / Q000378:metabolism
D010982:Platelet-Derived Growth Factor; D016222:Fibroblast Growth Factor 2