Is smooth muscle growth in primate arteries regulated by endothelial nitric oxide synthase?
OBJECTIVE
We investigated whether control of constitutive endothelial cell nitric oxide synthase (cNOS) and nitric oxide (NO) by changes in shear stress might be important for the regulation of smooth muscle cell (SMC) growth and vascular diameter.


METHODS
Bilateral femoral arteriovenous fistulas were placed in baboons to increase the blood flow in the external iliac arteries. At 2 months, the fistula was ligated on one side to restore normal flow (flow switch).


RESULTS
In response to flow switch and a decrease in shear stress, iliac artery lumenal area decreased and SMC proliferation was induced. A decline in NO production, cNOS messenger RNA (mRNA), and protein were associated with these biological effects. In a subset of animals with iliac arteries under high flow, infusion of N(omega)-nitro-L-arginine, an inhibitor of cNOS, did not induce proliferation.


CONCLUSIONS
Shear stress can regulate cNOS, vasoconstriction, and SMC proliferation. A decrease in nitric oxide may be necessary, but is not sufficient to induce SMC proliferation in response to a decrease in blood flow.
Mattsson
E J
EJ
Department of Surgery, Sahlgrenska Universitetssjukhuset, Goteborg, Sweden.
Geary
R L
RL
Kraiss
L W
LW
Vergel
S
S
Liao
J K
JK
Corson
M A
MA
Au
Y P
YP
Hanson
S R
SR
Clowes
A W
AW
D000818:Animals; D007083:Iliac Artery / Q000166:cytology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000502:physiology*; D009569:Nitric Oxide / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000502:physiology*; D052250:Nitric Oxide Synthase Type III; D019335:Nitroarginine / Q000494:pharmacology; D010215:Papio; D012333:RNA, Messenger / Q000032:analysis; D013314:Stress, Mechanical
D012333:RNA, Messenger; D019335:Nitroarginine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III