Background and purpose: The urothelium represents "the tightest and most impermeable barrier in the body." We investigated the distribution of paclitaxel (PTX) in the ureteral wall after the inflation of a paclitaxel-eluting balloon (PEB) in an attempt to elucidate the possibility of clinical application of PEBs in the ureter.
Materials and methods: Nine domestic pigs were used. Nine PEBs and nine conventional percutaneous angioplasty balloons (CB) were inflated in the right and left ureter of each animal, respectively. The ureter treated by CB was the control for the contralateral ureter. Specimens were removed: Immediately after inflation (group A), after 12 hours (group B), and after 24 hours (group C). Two samples were obtained from each ureter of groups A, B and C. One sample was investigated by nuclear magnetic resonance spectroscopy (NMR), the other by histology and immunohistochemistry (IHC) using a specific for PTX polyclonal antibody.
Results: Reduced inflammation was observed in the group B and C samples in comparison with their controls. PTX was distributed mostly in the urothelium and submucosal layer in group A (IHC). The agent was present in the urothelial, submucosal, and muscle layer in groups B and C. The concentration of PTX (NMR) has been reduced in group C compared with the tissue extracts of group B.
Conclusion: The distribution of PTX includes the urothelial, submucosal, and smooth muscle layers. Inflammation was reduced in the case of drug-eluting balloons.