Introduction: A common problem encountered in routine daily practice of cardiovascular surgery is migration of smooth muscle cells leading to intimal hyperplasia developing at vascular anastomosis sites which then causes luminal narrowing. The aim of this study was to investigate the antiproliferative effect of 1,25 (OH)₂D₃ on intimal hyperplasia.
Material and methods: Twenty-one male white New Zealand rabbits weighing 2-3 kg were selected. There were 3 groups of animals each consisting of 7 rabbits. Group 1 was the control group. Group 2 was the sham group and group 3 consisted of rabbits receiving 1,25 (OH)₂D₃. The right carotid arteries of the subjects in groups 2 and 3 were transected and re-anastomosed. A daily dose of 25 ng 1,25 (OH)₂D₃ per 100 γ body weight was administered for 14 days to rabbits in group 3. Rabbits in group 2 were not subject to any pharmaceutical agent. All the subjects were sacrificed at the end of the 28th postoperative day. Their right carotid arteries were resected and then investigated histopathologically.
Results: Intimal thickness and intimal area were measured as significantly lower in group 1 when compared with the other groups (p = 0.004). In group 3, the ratios of thickness of tunica intima/thickness of tunica media and area of tunica intima/area of tunica media were significantly lower than those of group 2 (p = 0.015, p = 0.003).
Conclusions: 1,25 (OH)₂D₃, the active metabolite of vitamin D, reduces the intimal hyperplasia developing after vascular anastomoses.