[Endovascular brachytherapy to prevent restenosis after angioplasty]

In vitro comparison of the antiproliferative effects of rhenium-186 and rhenium-188 on human aortic endothelial cells

PURPOSE

Rhenium-186 ((186)Re) and rhenium-188 ((188)Re) are promising radionuclides for the inhibition of restenosis after percutaneous transluminal angioplasty or other vascular interventions. Until now the maximal dose tolerance of endothelial cells has not been clearly known.

MATERIALS AND METHODS

To characterize the effects of local irradiation treatment, human aortic endothelial cells (ECs) were incubated with different doses of (186)Re and (188)Re. Two days after plating, ECs received treatment for a period of 5 days. The total radiation doses applied were 1, 4, 8, 16, and 32 Gy. On days 1, 3, 5, 7, and 12 after initial rhenium incubation, cell growth, clonogenic activity, cell-cycle distribution, and cytoskeletal architecture were evaluated.

RESULTS

From the first day on, a dose-dependent growth inhibition was observed. Cumulative doses of ≥32 Gy caused a weak colony formation and significant alterations in the cytoskeletal architecture. An increased fraction of cells in G2/M phase was seen for cumulative radiation doses of ≥16 Gy. Interestingly, there were no significant differences between (186)Re and (188)Re.

CONCLUSION

Even for low dose rates of β particles a dose-dependent proliferation inhibition of ECs is seen. Doses beyond 32 Gy alter the cytoskeletal architecture with possibly endothelial dysfunction and late thrombosis.

Reduction of Stenosis Due to Intimal Hyperplasia After Stent Supported Angioplasty of Peripheral Arteries by Local Administration of Paclitaxel in Swine

PURPOSE

To assess if local intra-arterial administration of paclitaxel using drug-coated balloons or an admixture of paclitaxel to contrast medium inhibits stenosis after percutanous transluminal angioplasty (PTA) of peripheral arteries in a porcine overstretch model.

METHODS

Neointimal proliferation and stenosis were induced by overstretch and stenting of 40 peripheral arteries in 20 pigs. Paclitaxel was administered locally during PTA using coated balloons (n = 20) or dissolved in contrast medium (n = 10). Conventional balloons and contrast medium were used in a control group (n = 10). Reangiography with quantitative analysis was performed after 5 weeks.

RESULTS

On reangiography diameter stenosis and late lumen loss were significantly reduced by both methods of local drug delivery compared with control group; minimal luminal diameter was significantly larger in the treatment groups.

CONCLUSIONS

Local short-term administration of paclitaxel during PTA of peripheral arteries using balloons or contrast medium as drug carriers reduced stenosis due to intimal hyperplasia.