984-29 Modulation of s-Homocysteine Associated with Intimal Thickening After Balloon Angioplasty Injury of the Rabbit Iliac Artery

Hyperhomocysteinemia is associated with arterial disease. Elevated levels of s-homocystein (Hcy) have been suggested to cause intimal injury and smooth muscle cell recruitment. Since a similar vessel wall response is also seen in restenotic lesions after balloon angioplasty, we studied the effects of moderate reduction and elevation of s-Hcy levels on the potentiation of arterial wall thickening after balloon injury in the iliac artery of rabbits.Methods16 female Chinchilla (Chbb:CH) rabbits were randomized to receive either Hcy-lowering therapy with pryridoxin, cobalamin, folic acid and Betain (group 1, weight 3.9 kg) or Hcy-increasing therapy with methionin (group 2, weight 3.8 kg, p=NS). After one week transcatheter balloon angioplasty was performed via right carotidotomy using an oversized (3.0mm) balloon catheter. Angiography was performed after angioplasty and after 9 weeks, when the rabbits were sacrified and perfusion-fixed. Injury response was measured by histomorphometry.ResultsPre-treatment s-HcY-levels were 17.2+6.9 vs 16.7+5.3 mmol/l for group 1 and 2 (p =NS), at the time of angioplasty 13.5+2.9 vs 20.0+7.0 (p<0.05) and these differences remained throughout the study. Histomorphometry showed intima/media area ratio 0.44+0.17 vs 0.73+0.24 (p=0.03), intima/media thickness ratio 1.11+0.93 vs 2.00+2.79 (p=0.03) and absolute intima thickness 0.11+0.01 vs 0.22±0.04mm (p=0.03) for group 1 and 2 resp. Angiographic videodensitometry was consistent with the histomorphometric findings.ConclusionHyperhomocysteinemia contributes to intimal thickening in the rabbit iliac artery after balloon angioplasty injury