Kg. Birukov et al., STRETCH AFFECTS PHENOTYPE AND PROLIFERATION OF VASCULAR SMOOTH-MUSCLECELLS, Molecular and cellular biochemistry, 144(2), 1995, pp. 131-139
The exertion of periodic dynamic strain on the arterial wall is hypoth
esized to be relevant to smooth muscle cell morphology and function. T
his study has investigated the effect of cyclic mechanical stretching
on rabbit aortic smooth muscle cell proliferation and expression of co
ntractile phenotype protein markers. Cells were cultured on flexible-b
ottomed dishes and cyclic stretch was applied (frequency 30 cycles/min
, 15% elongation) using a Flexercell Strain unit. Cyclic stretch poten
tiated smooth muscle cell proliferation in serum-activated cultures bu
t not in cultures maintained in 0.5% fetal calf serum. Stretching indu
ced a serum-independent increase of h-caldesmon expression and this ef
fect was reversible following termination of mechanical stimulation. S
train was without effect on smooth muscle myosin or calponin expressio
n. In cells grown on laminin stretch-induced h-caldesmon expression wa
s more prominent than in cells cultured on collagen types I and IV, po
ly-L-lysine and gelatin. These data suggest that cyclic mechanical sti
mulation possesses dual effect on vascular smooth muscle cell phenotyp
e characteristics since it: 1) potentiates proliferation, an attribute
of a dedifferentiated phenotype; and 2) increases expression of h-cal
desmon considered a marker of a differentiated smooth muscle cell stat
e.