MECHANISMS OF STENOSIS AFTER ARTERIAL INJURY

  • 1 January 1983
    • journal article
    • research article
    • Vol. 49  (2) , 208-215
Abstract
The development of luminal narrowing in relationship to intimal thickening was investigated in rat common carotid artery denuded of endothelium. After denudation with a balloon embolectomy catheter endothelium was observed to regenerate from the ends of the denuded segment but not to cover the central third of the artery by 12 wk. Cross-sections of denuded (Evans blue stained) and reendothelialized (white) areas showed that intimal thickening in the blue, but not the white, region progressively increased with time and was maximal between 4 and 12 wk. Luminal narrowing was most pronounced at 2 wk (75%) and less at 12 wk (35%). The apparent discrepancy in these results was resolved by demonstrating that the vessel circumference in the blue region at the level of the internal elastic lamina was reduced at 2 wk and the same as controls at 12 wk; i.v. infusion of papaverine abolished this vasoconstriction of the left carotids at 1 wk after injury. Luminal narrowing early after injury is in large part due to smooth muscle contraction of the vessel and late due only to intimal thickening. During the period between 2 and 12 wk the fraction of the intima occupied by smooth muscle cells decreased markedly, but the total volume due to smooth muscle cells remained relatively constant. By DNA measurements arterial wall cell number is shown to be the same at 2 and 12 wk; Continued intimal thickening at late time points apparently is due to synthesis and accumulation of connective tissue without further increase in smooth muscle cell number.