Insulin increases reendothelialization and inhibits cell migration and neointimal growth after arterial injury.
OBJECTIVE
Insulin has both growth-promoting and protective vascular effects in vitro, however the predominant effect in vivo is unclear. We investigated the effects of insulin in vivo on neointimal growth after arterial injury.


RESULTS
Rats were given subcutaneous control (C) or insulin implants (3U/d;I) 3 days before arterial (carotid or aortic) balloon catheter injury. Normoglycemia was maintained by oral glucose and, after surgery, by intraperitoneal glucose infusion (saline in C). Insulin decreased intimal area (P<0.01) but did not change intimal cell proliferation or apoptosis. However, insulin inhibited cell migration into the intima (P<0.01) and increased expression of smooth muscle cell (SMC) differentiation markers (P<0.05). Insulin also increased reendothelialization (P<0.01) and the number of circulating progenitor cells (P<0.05).


CONCLUSIONS
These results are the first demonstration that insulin has a protective effect on both SMC and endothelium in vivo, resulting in inhibition of neointimal growth after vessel injury.
Department of Physiology, University of Toronto. Ontario, Canada.
Danna M
DM
Breen
Kalam K
KK
Chan
Jiwanjeet K
JK
Dhaliwall
Michael R
MR
Ward
Nael
N
Al Koudsi
Loretta
L
Lam
Melissa
M
De Souza
Husam
H
Ghanim
Paresh
P
Dandona
Duncan J
DJ
Stewart
Michelle P
MP
Bendeck
Adria
A
Giacca
D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects; D000818:Animals; D002340:Carotid Artery Diseases / Q000503:physiopathology*; D002465:Cell Movement / Q000502:physiology*; D023903:Coronary Restenosis / Q000503:physiopathology; D004730:Endothelium, Vascular; D007328:Insulin / Q000502:physiology*; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000293:injuries / Q000503:physiopathology*; D032389:Myocytes, Smooth Muscle / Q000502:physiology; D051381:Rats; D017539:Tunica Intima / Q000503:physiopathology*
D007328:Insulin