VITAMIN-D-3 EXACERBATES INTIMAL HYPERPLASIA IN BALLOON-INJURED ARTERIES

Although a high dose of vitamin D-3 is known to cause arterial calcifi cation and degeneration, its effect on intimal hyperplasia has never b een studied. The aim of this study was to examine the influence of a m oderate supplement of vitamin D-3 on intimal hyperplasia in the balloo n-injured rat carotid artery. Forty-four rats had balloon injury to th e carotid artery; 22 were given oral vitamin D-3 supplementation (0.25 mu g kg(-1) day(-1)). Animals were killed at 4 weeks and the carotid arteries were perfusion fixed and assessed morphometrically by means o f computerized image analysis of transverse sections. Mean (s.e.m.) in timal area was significantly greater in the vitamin D-3-treated animal s than in controls: 0.92 (0.05) versus 0.71 (0.07) mm(2) (P = 0.02). T he area of the media of both injured and uninjured arteries was not in fluenced by vitamin D-3 administration. A small dose of vitamin D-3 re sulted in significant exacerbation of intimal hyperplasia in this rat carotid artery model and raises the question of the role of dietary vi tamin D-3 in restenosis following vascular intervention.