EW-7197 eluting nano-fiber covered self-expandable metallic stent to prevent granulation tissue formation in a canine urethral model
Purpose: To evaluate an EW-7197-eluting nanofiber-covered stent (NFCS) for its ability to suppress granulation tissue formation after stent placement in a canine urethral model.
Materials and Methods: All experiments were approved by the animal research committee. A total of 12 NFCSs were placed in the proximal and distal urethras of six dogs, divided into two groups of three dogs each. The control stent (CS) group received standard NFCSs, while the drug stent (DS) group received EW-7197 (1000 μg)-eluting NFCSs. All dogs were sacrificed 8 weeks post-stent placement, and histologic findings of the stented urethra were compared using the Mann-Whitney U test.
Results: Stent placement was technically successful in all dogs with no procedure-related complications. Urethrographic analysis showed that the mean luminal diameter was significantly larger in the DS group compared to the CS group at both 4 and 8 weeks post-stent placement (all p < 0.001). Histological examination revealed that the DS group had significantly lower mean thicknesses of the papillary projection, submucosal fibrosis, number of epithelial layers, and collagen deposition compared to the CS group (all p < 0.001). However, the mean degree of inflammatory cell infiltration did not significantly differ between the groups (p > 0.05).
Conclusion: The TEW-7197-eluting NFCS is effective and safe in suppressing granulation tissue formation after stent placement in a canine urethral model.