Early collateral and microvascular adaptations to intestinal artery
occlusion in the rat.
Unthank, Joseph L., J. Craig Nixon, Harold M. Burkhart, Steven W.
Fath, and Michael C. Dalsing.
Departments of Surgery, and Physiology and Biophysics, Indiana
University Medical Center, Indianapolis, IN 46202
APStracts 3:0081H, 1996.
The technique to repeatedly observe exactly the same vessels in the
rat intestine was used to investigate vascular compensation during
the first week following abrupt arterial ligation. A collateral
-dependent tissue region was created by ligation of 3-4 sequential
intestinal arteries. At the center of the collateral-dependent
region, arterial pressure decreased from 96+/-3.7 to 29+/-2.5 mmHg
and intestinal blood flow fell 80% during maximal dilation initially
post-ligation. One week later, pressure and blood flow at center had
increased 31% and 250% respectively. Relative to pre-ligation values,
the only compensatory adaptation was an enlargement (31+/-11%) of the
collateral arteries located between normal tissue and the center; no
increase was observed for the diameter or numbers of arterioles or
collateral arteries at center. Wall shear rate was increased 173+/
-35% initially post-ligation at the site where luminal enlargement
occurred. The selective enlargement of collateral arteries away from
the center region is consistent with the hypothesis that collateral
enlargement is induced by chronic increases in wall shear rate and
can occur independently of tissue ischemia.
Received 20 November 1995; accepted in final form 8 February
1996.
APS Manuscript Number H1085-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 March 96